From 30e4c0440d4ea9596333b1d6e563b7dc80129953 Mon Sep 17 00:00:00 2001
From: Manfred Riem <15701806+mnriem@users.noreply.github.com>
Date: Thu, 29 Oct 2026 07:14:58 -0500
Subject: [PATCH 1/4] fix: reject unsafe self-upgrade installer paths

Reject relative and working-directory installer lookup results before registry probes and self-upgrades, including symlinks to working-directory executables.

Assisted-by: GitHub Copilot (model: GPT-6.1 Sol, autonomous)
Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
---
 src/specify_cli/_version.py                   |  21 +-
 .../specify_cli/selfs/test_command_upgrade.py |  43 +++-
 tests/specify_cli/test_version_detection.py   | 239 +++++++++++++++---
 tests/specify_cli/test_version_execution.py   |  21 +-
 .../specify_cli/test_version_verification.py  |  23 +-
 5 files changed, 273 insertions(+), 74 deletions(-)

diff --git a/src/specify_cli/_version.py b/src/specify_cli/_version.py
index 93b4c6a618..2dedbe7c93 100644
--- a/src/specify_cli/_version.py
+++ b/src/specify_cli/_version.py
@@ -477,6 +477,19 @@ def _editable_marker_seen() -> bool:
     return editable_root is not None and _git_ancestor(editable_root) is not None
 
 
+def _find_installer(name: str) -> str | None:
+    """Resolve an installer without trusting working-directory executables."""
+    resolved = shutil.which(name)
+    if resolved is None:
+        return None
+    installer = Path(resolved)
+    # Windows lookup may prepend cwd even when PATH contains only absolute
+    # directories. Never absolutize that result or fall back to a bare command.
+    if not installer.is_absolute() or installer.resolve().parent == Path.cwd().resolve():
+        return None
+    return resolved
+
+
 def _detect_install_method(
     argv0: str | None = None,
     include_signals: bool = False,
@@ -530,7 +543,7 @@ def _detect_install_method(
     consulted: list[str] = []
     if _tier3_registry_lookup_allowed(argv0_path):
         uv_tool_match = False
-        uv_bin = shutil.which("uv")
+        uv_bin = _find_installer("uv")
         if uv_bin is not None:
             consulted.append("uv tool list")
             try:
@@ -550,7 +563,7 @@ def _detect_install_method(
                 pass
 
         pipx_match = False
-        pipx_bin = shutil.which("pipx")
+        pipx_bin = _find_installer("pipx")
         if pipx_bin is not None:
             consulted.append("pipx list --json")
             try:
@@ -631,7 +644,7 @@ def _assemble_installer_argv(
     source_spec = _source_spec(target_tag)
 
     if method == _InstallMethod.UV_TOOL:
-        uv_bin = shutil.which("uv")
+        uv_bin = _find_installer("uv")
         if uv_bin is None:
             return None
         return [
@@ -647,7 +660,7 @@ def _assemble_installer_argv(
     if method == _InstallMethod.PIPX:
         # pipx 1.5+ removed `--spec`; PACKAGE_SPEC is now positional and the
         # package name is auto-detected from the source's pyproject.toml.
-        pipx_bin = shutil.which("pipx")
+        pipx_bin = _find_installer("pipx")
         if pipx_bin is None:
             return None
         return [
diff --git a/tests/specify_cli/selfs/test_command_upgrade.py b/tests/specify_cli/selfs/test_command_upgrade.py
index 5a39a9ddb7..447394f1df 100644
--- a/tests/specify_cli/selfs/test_command_upgrade.py
+++ b/tests/specify_cli/selfs/test_command_upgrade.py
@@ -1,18 +1,45 @@
 """Command tests for ``specify self upgrade``."""
 
+import sys
 from unittest.mock import patch
 
 import pytest
 
 from specify_cli import app
-from tests.specify_cli.self_upgrade_helpers import runner, strip_ansi
+from tests.specify_cli.self_upgrade_helpers import _InstallMethod, runner, strip_ansi
+
+
+@pytest.mark.parametrize(("method", "name"), [("uv-tool", "uv"), ("pipx", "pipx")])
+@pytest.mark.parametrize("absolute", [False, True])
+def test_unsafe_installer_lookup_aborts_without_execution(
+    monkeypatch, tmp_path, method, name, absolute
+):
+    monkeypatch.chdir(tmp_path)
+    decoy = tmp_path / name
+    decoy.write_text("decoy; must never be executed\n", encoding="utf-8")
+    decoy.chmod(0o755)
+    unsafe_path = str(decoy) if absolute else f"./{name}"
+
+    with patch(
+        "specify_cli._version._detect_install_method",
+        return_value=_InstallMethod(method),
+    ), patch(
+        "specify_cli._version.shutil.which", return_value=unsafe_path
+    ), patch(
+        "specify_cli._version._get_installed_version", return_value="0.7.5"
+    ), patch("specify_cli._version.subprocess.run") as mock_run:
+        result = runner.invoke(app, ["self", "upgrade", "--tag", "v0.7.6"])
+
+    assert result.exit_code == 3
+    assert f"Installer {name} not found on PATH" in strip_ansi(result.output)
+    mock_run.assert_not_called()
 
 
 class TestTagValidation:
     """--tag option parsing and command help."""
 
     def test_valid_stable_tag(self, uv_tool_argv0, clean_environ):
-        with patch("specify_cli._version.shutil.which", return_value="uv"), patch(
+        with patch("specify_cli._version.shutil.which", return_value=sys.executable), patch(
             "specify_cli._version._get_installed_version", return_value="0.7.5"
         ):
             result = runner.invoke(
@@ -22,7 +49,7 @@ def test_valid_stable_tag(self, uv_tool_argv0, clean_environ):
         assert result.exit_code == 0
 
     def test_valid_dev_suffix_tag(self, uv_tool_argv0, clean_environ):
-        with patch("specify_cli._version.shutil.which", return_value="uv"), patch(
+        with patch("specify_cli._version.shutil.which", return_value=sys.executable), patch(
             "specify_cli._version._get_installed_version", return_value="0.7.5"
         ):
             result = runner.invoke(
@@ -33,7 +60,7 @@ def test_valid_dev_suffix_tag(self, uv_tool_argv0, clean_environ):
         assert "Target version: v0.8.0.dev0" in strip_ansi(result.output)
 
     def test_valid_rc_tag(self, uv_tool_argv0, clean_environ):
-        with patch("specify_cli._version.shutil.which", return_value="uv"), patch(
+        with patch("specify_cli._version.shutil.which", return_value=sys.executable), patch(
             "specify_cli._version._get_installed_version", return_value="0.7.5"
         ):
             result = runner.invoke(
@@ -45,7 +72,7 @@ def test_valid_rc_tag(self, uv_tool_argv0, clean_environ):
     def test_valid_beta_dot_tag_uses_pep440_equivalent_for_noop(
         self, uv_tool_argv0, clean_environ
     ):
-        with patch("specify_cli._version.shutil.which", return_value="uv"), patch(
+        with patch("specify_cli._version.shutil.which", return_value=sys.executable), patch(
             "specify_cli._version._get_installed_version", return_value="1.0.0b1"
         ):
             result = runner.invoke(
@@ -58,7 +85,7 @@ def test_valid_beta_dot_tag_uses_pep440_equivalent_for_noop(
         )
 
     def test_valid_build_metadata_tag(self, uv_tool_argv0, clean_environ):
-        with patch("specify_cli._version.shutil.which", return_value="uv"), patch(
+        with patch("specify_cli._version.shutil.which", return_value=sys.executable), patch(
             "specify_cli._version._get_installed_version", return_value="0.7.5"
         ):
             result = runner.invoke(
@@ -71,7 +98,7 @@ def test_valid_build_metadata_tag(self, uv_tool_argv0, clean_environ):
     def test_uppercase_v_prefix_is_folded_to_lowercase(
         self, uv_tool_argv0, clean_environ
     ):
-        with patch("specify_cli._version.shutil.which", return_value="uv"), patch(
+        with patch("specify_cli._version.shutil.which", return_value=sys.executable), patch(
             "specify_cli._version._get_installed_version", return_value="0.7.5"
         ):
             result = runner.invoke(
@@ -84,7 +111,7 @@ def test_uppercase_v_prefix_is_folded_to_lowercase(
     def test_valid_prerelease_with_build_metadata_tag(
         self, uv_tool_argv0, clean_environ
     ):
-        with patch("specify_cli._version.shutil.which", return_value="uv"), patch(
+        with patch("specify_cli._version.shutil.which", return_value=sys.executable), patch(
             "specify_cli._version._get_installed_version", return_value="0.7.5"
         ):
             result = runner.invoke(
diff --git a/tests/specify_cli/test_version_detection.py b/tests/specify_cli/test_version_detection.py
index c769665920..1d19d3321c 100644
--- a/tests/specify_cli/test_version_detection.py
+++ b/tests/specify_cli/test_version_detection.py
@@ -4,6 +4,7 @@
 import json
 import os
 import subprocess
+import sys
 from pathlib import Path
 from unittest.mock import patch
 
@@ -90,10 +91,10 @@ def test_tier3_uv_tool_when_registry_lists_exact_name(
         monkeypatch.setattr("sys.argv", [str(tmp_path / "missing" / "specify")])
 
         def fake_which(name):
-            return "uv" if name == "uv" else None
+            return sys.executable if name == "uv" else None
 
         def fake_run(argv, *args, **kwargs):
-            if argv[:3] == ["uv", "tool", "list"]:
+            if argv[:3] == [sys.executable, "tool", "list"]:
                 return subprocess.CompletedProcess(
                     args=argv,
                     returncode=0,
@@ -116,7 +117,7 @@ def test_unresolved_bare_argv0_skips_tier3_registry_detection(self, monkeypatch)
         monkeypatch.setattr("sys.argv", ["specify"])
 
         def fake_which(name):
-            return "uv" if name == "uv" else None
+            return sys.executable if name == "uv" else None
 
         def fake_run(argv, *args, **kwargs):
             return subprocess.CompletedProcess(
@@ -143,11 +144,11 @@ def fake_which(name):
             if name == "specify":
                 return str(missing_specify)
             if name == "uv":
-                return "uv"
+                return sys.executable
             return None
 
         def fake_run(argv, *args, **kwargs):
-            if argv[:3] == ["uv", "tool", "list"]:
+            if argv[:3] == [sys.executable, "tool", "list"]:
                 return subprocess.CompletedProcess(
                     args=argv,
                     returncode=0,
@@ -196,10 +197,10 @@ def test_tier3_uv_tool_ignores_substring_false_positive(
         unsupported_argv0,
     ):
         def fake_which(name):
-            return "uv" if name == "uv" else None
+            return sys.executable if name == "uv" else None
 
         def fake_run(argv, *args, **kwargs):
-            if argv[:3] == ["uv", "tool", "list"]:
+            if argv[:3] == [sys.executable, "tool", "list"]:
                 return subprocess.CompletedProcess(
                     args=argv,
                     returncode=0,
@@ -221,10 +222,10 @@ def test_tier3_uv_tool_does_not_override_absolute_unsupported_entrypoint(
         unsupported_argv0,
     ):
         def fake_which(name):
-            return "uv" if name == "uv" else None
+            return sys.executable if name == "uv" else None
 
         def fake_run(argv, *args, **kwargs):
-            if argv[:3] == ["uv", "tool", "list"]:
+            if argv[:3] == [sys.executable, "tool", "list"]:
                 return subprocess.CompletedProcess(
                     args=argv,
                     returncode=0,
@@ -257,11 +258,11 @@ def fake_which(name):
             if name == "specify":
                 return str(fake_specify)
             if name == "uv":
-                return "uv"
+                return sys.executable
             return None
 
         def fake_run(argv, *args, **kwargs):
-            if argv[:3] == ["uv", "tool", "list"]:
+            if argv[:3] == [sys.executable, "tool", "list"]:
                 return subprocess.CompletedProcess(
                     args=argv,
                     returncode=0,
@@ -323,14 +324,170 @@ def test_path_lookup_resolve_oserror_returns_unresolved_lookup_path(self):
         assert result == Path("/broken/specify")
 
 
+class TestInstallerResolution:
+    @pytest.mark.parametrize(
+        ("method", "name"),
+        [(_InstallMethod.UV_TOOL, "uv"), (_InstallMethod.PIPX, "pipx")],
+    )
+    @pytest.mark.parametrize(
+        "location",
+        ["bare", "current-relative", "relative-directory", "windows-relative", "current-absolute"],
+    )
+    def test_unsafe_lookup_result_is_not_used_for_upgrade_or_registry_probe(
+        self, monkeypatch, tmp_path, method, name, location
+    ):
+        monkeypatch.chdir(tmp_path)
+        paths = {
+            "bare": name,
+            "current-relative": f"./{name}",
+            "relative-directory": f"bin/{name}",
+            "windows-relative": f".\\{name}.exe",
+            "current-absolute": str(tmp_path / name),
+        }
+        decoy = tmp_path / name
+        decoy.write_text("#!/bin/sh\n", encoding="utf-8")
+        decoy.chmod(0o755)
+        monkeypatch.setattr("sys.argv", [str(tmp_path / "missing" / "specify")])
+
+        with patch(
+            "specify_cli._version.shutil.which",
+            side_effect=lambda command: paths[location] if command == name else None,
+        ), patch(
+            "specify_cli._version._editable_marker_seen", return_value=False
+        ), patch("specify_cli._version.subprocess.run") as mock_run:
+            argv = _assemble_installer_argv(method, "v0.7.6")
+            detected, signals = _detect_install_method(include_signals=True)
+
+        assert argv is None
+        assert detected == _InstallMethod.UNSUPPORTED
+        assert signals.installer_registries_consulted == ()
+        mock_run.assert_not_called()
+
+    @pytest.mark.parametrize(
+        ("method", "name"),
+        [(_InstallMethod.UV_TOOL, "uv"), (_InstallMethod.PIPX, "pipx")],
+    )
+    def test_absolute_installer_outside_working_directory_is_preserved(
+        self, monkeypatch, tmp_path, method, name
+    ):
+        project = tmp_path / "project"
+        project.mkdir()
+        monkeypatch.chdir(project)
+        installer = tmp_path / "installed tools" / name
+        installer.parent.mkdir()
+        installer.write_text("#!/bin/sh\n", encoding="utf-8")
+        installer.chmod(0o755)
+
+        with patch(
+            "specify_cli._version.shutil.which", return_value=str(installer)
+        ):
+            argv = _assemble_installer_argv(method, "v0.7.6")
+
+        assert argv is not None
+        assert argv[0] == str(installer)
+
+    @pytest.mark.parametrize(
+        ("method", "name"),
+        [(_InstallMethod.UV_TOOL, "uv"), (_InstallMethod.PIPX, "pipx")],
+    )
+    @pytest.mark.parametrize("path_entry", ["empty", "dot", "relative", "current-absolute"])
+    def test_real_lookup_rejects_working_directory_and_relative_path_entries(
+        self, monkeypatch, tmp_path, method, name, path_entry
+    ):
+        monkeypatch.chdir(tmp_path)
+        monkeypatch.delenv("NoDefaultCurrentDirectoryInExePath", raising=False)
+        monkeypatch.setenv("PATHEXT", ".EXE")
+        filename = f"{name}.exe" if os.name == "nt" else name
+        (tmp_path / "bin").mkdir()
+        for directory in (tmp_path, tmp_path / "bin"):
+            executable = directory / filename
+            executable.write_text("decoy; must never be executed\n", encoding="utf-8")
+            executable.chmod(0o755)
+        entries = {
+            "empty": "",
+            "dot": ".",
+            "relative": "bin",
+            "current-absolute": str(tmp_path),
+        }
+        monkeypatch.setenv("PATH", entries[path_entry])
+
+        assert _assemble_installer_argv(method, "v0.7.6") is None
+
+    @pytest.mark.parametrize(
+        ("method", "name"),
+        [(_InstallMethod.UV_TOOL, "uv"), (_InstallMethod.PIPX, "pipx")],
+    )
+    def test_real_lookup_preserves_installed_tool_on_absolute_path(
+        self, monkeypatch, tmp_path, method, name
+    ):
+        project = tmp_path / "project"
+        project.mkdir()
+        monkeypatch.chdir(project)
+        directory = tmp_path / "installed tools"
+        directory.mkdir()
+        filename = f"{name}.exe" if os.name == "nt" else name
+        installer = directory / filename
+        installer.write_text("installer fixture; never executed\n", encoding="utf-8")
+        installer.chmod(0o755)
+        monkeypatch.setenv("PATH", str(directory))
+        monkeypatch.setenv("PATHEXT", ".EXE")
+
+        argv = _assemble_installer_argv(method, "v0.7.6")
+
+        assert argv is not None
+        assert Path(argv[0]) == installer
+
+    @pytest.mark.skipif(sys.platform != "win32", reason="Windows implicit cwd search")
+    @pytest.mark.parametrize(
+        ("method", "name"),
+        [(_InstallMethod.UV_TOOL, "uv"), (_InstallMethod.PIPX, "pipx")],
+    )
+    def test_windows_implicit_cwd_lookup_cannot_shadow_installed_tool(
+        self, monkeypatch, tmp_path, method, name
+    ):
+        project = tmp_path / "project"
+        project.mkdir()
+        directory = tmp_path / "installed tools"
+        directory.mkdir()
+        for parent in (project, directory):
+            executable = parent / f"{name}.exe"
+            executable.write_text("fixture; must never be executed\n", encoding="utf-8")
+        monkeypatch.chdir(project)
+        monkeypatch.setenv("PATH", str(directory))
+        monkeypatch.setenv("PATHEXT", ".EXE")
+        monkeypatch.delenv("NoDefaultCurrentDirectoryInExePath", raising=False)
+
+        argv = _assemble_installer_argv(method, "v0.7.6")
+
+        assert argv is None or Path(argv[0]) == directory / f"{name}.exe"
+
+    @pytest.mark.skipif(os.name == "nt", reason="requires unprivileged symlinks")
+    def test_absolute_symlink_to_working_directory_installer_is_rejected(
+        self, monkeypatch, tmp_path
+    ):
+        project = tmp_path / "project"
+        project.mkdir()
+        monkeypatch.chdir(project)
+        decoy = project / "uv"
+        decoy.write_text("#!/bin/sh\n", encoding="utf-8")
+        decoy.chmod(0o755)
+        installer = tmp_path / "uv"
+        installer.symlink_to(decoy)
+
+        with patch(
+            "specify_cli._version.shutil.which", return_value=str(installer)
+        ):
+            assert _assemble_installer_argv(_InstallMethod.UV_TOOL, "v0.7.6") is None
+
+
 class TestArgvAssemblyUvTool:
     """uv-tool installer argv shape."""
 
     def test_stable_tag_produces_expected_argv(self):
-        with patch("specify_cli._version.shutil.which", return_value="uv"):
+        with patch("specify_cli._version.shutil.which", return_value=sys.executable):
             argv = _assemble_installer_argv(_InstallMethod.UV_TOOL, "v0.7.6")
         assert argv == [
-            "uv",
+            sys.executable,
             "tool",
             "install",
             "specify-cli",
@@ -340,7 +497,7 @@ def test_stable_tag_produces_expected_argv(self):
         ]
 
     def test_dev_suffix_tag_embedded_literally(self):
-        with patch("specify_cli._version.shutil.which", return_value="uv"):
+        with patch("specify_cli._version.shutil.which", return_value=sys.executable):
             argv = _assemble_installer_argv(_InstallMethod.UV_TOOL, "v0.8.0.dev0")
         assert "git+https://github.com/github/spec-kit.git@v0.8.0.dev0" in argv
         assert (
@@ -357,7 +514,7 @@ class TestBareUpgradeUvTool:
 
     def test_happy_path_end_to_end(self, uv_tool_argv0, clean_environ):
         with patch("specify_cli.authentication.http.urllib.request.urlopen") as mock_urlopen, patch(
-            "specify_cli._version.shutil.which", return_value="uv"
+            "specify_cli._version.shutil.which", return_value=sys.executable
         ), patch("specify_cli._version.subprocess.run") as mock_run, patch(
             "specify_cli._version._get_installed_version", return_value="0.7.5"
         ):
@@ -380,7 +537,7 @@ def test_one_user_action_no_prompt(self, uv_tool_argv0, clean_environ):
         # The single `invoke` represents the single user action — no prompt.
         # If a prompt existed, runner.invoke would hang waiting for input.
         with patch("specify_cli.authentication.http.urllib.request.urlopen") as mock_urlopen, patch(
-            "specify_cli._version.shutil.which", return_value="uv"
+            "specify_cli._version.shutil.which", return_value=sys.executable
         ), patch("specify_cli._version.subprocess.run") as mock_run, patch(
             "specify_cli._version._get_installed_version", return_value="0.7.5"
         ):
@@ -402,7 +559,7 @@ def test_already_latest_exits_zero_no_subprocess(
         with patch("specify_cli.authentication.http.urllib.request.urlopen") as mock_urlopen, patch(
             "specify_cli._version.subprocess.run"
         ) as mock_run, patch(
-            "specify_cli._version.shutil.which", return_value="uv"
+            "specify_cli._version.shutil.which", return_value=sys.executable
         ), patch("specify_cli._version._get_installed_version", return_value="0.7.6"):
             mock_urlopen.return_value = mock_urlopen_response({"tag_name": "v0.7.6"})
             result = runner.invoke(app, ["self", "upgrade"])
@@ -420,7 +577,7 @@ def test_trailing_zero_equivalent_version_reports_latest_not_newer(
         with patch("specify_cli.authentication.http.urllib.request.urlopen") as mock_urlopen, patch(
             "specify_cli._version.subprocess.run"
         ) as mock_run, patch(
-            "specify_cli._version.shutil.which", return_value="uv"
+            "specify_cli._version.shutil.which", return_value=sys.executable
         ), patch("specify_cli._version._get_installed_version", return_value="1.0"):
             mock_urlopen.return_value = mock_urlopen_response({"tag_name": "v1.0.0"})
             result = runner.invoke(app, ["self", "upgrade"])
@@ -437,7 +594,7 @@ def test_dev_build_ahead_of_release_reports_newer_noop(
         with patch("specify_cli.authentication.http.urllib.request.urlopen") as mock_urlopen, patch(
             "specify_cli._version.subprocess.run"
         ) as mock_run, patch(
-            "specify_cli._version.shutil.which", return_value="uv"
+            "specify_cli._version.shutil.which", return_value=sys.executable
         ), patch("specify_cli._version._get_installed_version", return_value="0.7.7.dev0"):
             mock_urlopen.return_value = mock_urlopen_response({"tag_name": "v0.7.6"})
             result = runner.invoke(app, ["self", "upgrade"])
@@ -452,7 +609,7 @@ def test_unparseable_current_version_does_not_false_noop(
         with patch("specify_cli.authentication.http.urllib.request.urlopen") as mock_urlopen, patch(
             "specify_cli._version.subprocess.run"
         ) as mock_run, patch(
-            "specify_cli._version.shutil.which", return_value="uv"
+            "specify_cli._version.shutil.which", return_value=sys.executable
         ), patch("specify_cli._version._get_installed_version", return_value="release-main"):
             mock_urlopen.return_value = mock_urlopen_response({"tag_name": "v0.7.6"})
             mock_run.side_effect = [
@@ -473,7 +630,7 @@ def test_unparseable_resolved_target_fails_before_literal_noop(
         with patch("specify_cli.authentication.http.urllib.request.urlopen") as mock_urlopen, patch(
             "specify_cli._version.subprocess.run"
         ) as mock_run, patch(
-            "specify_cli._version.shutil.which", return_value="uv"
+            "specify_cli._version.shutil.which", return_value=sys.executable
         ), patch("specify_cli._version._get_installed_version", return_value="release-main"):
             mock_urlopen.return_value = mock_urlopen_response({"tag_name": "release-main"})
             result = runner.invoke(app, ["self", "upgrade"])
@@ -488,7 +645,7 @@ def test_unparseable_resolved_target_fails_before_literal_noop(
     def test_pinned_older_tag_still_runs_installer(
         self, uv_tool_argv0, clean_environ
     ):
-        with patch("specify_cli._version.shutil.which", return_value="uv"), patch(
+        with patch("specify_cli._version.shutil.which", return_value=sys.executable), patch(
             "specify_cli._version.subprocess.run"
         ) as mock_run, patch(
             "specify_cli._version._get_installed_version", return_value="0.7.6"
@@ -510,7 +667,7 @@ def test_pinned_older_tag_still_runs_installer(
     def test_pinned_rc_tag_uses_canonical_version_equality_for_noop(
         self, uv_tool_argv0, clean_environ
     ):
-        with patch("specify_cli._version.shutil.which", return_value="uv"), patch(
+        with patch("specify_cli._version.shutil.which", return_value=sys.executable), patch(
             "specify_cli._version._get_installed_version", return_value="1.0.0rc1"
         ):
             result = runner.invoke(app, ["self", "upgrade", "--tag", "v1.0.0-rc1"])
@@ -530,7 +687,7 @@ def test_dry_run_without_tag_resolves_network_but_no_subprocess(
         with patch("specify_cli.authentication.http.urllib.request.urlopen") as mock_urlopen, patch(
             "specify_cli._version.subprocess.run"
         ) as mock_run, patch(
-            "specify_cli._version.shutil.which", return_value="uv"
+            "specify_cli._version.shutil.which", return_value=sys.executable
         ), patch("specify_cli._version._get_installed_version", return_value="0.7.5"):
             mock_urlopen.return_value = mock_urlopen_response({"tag_name": "v0.7.6"})
             result = runner.invoke(app, ["self", "upgrade", "--dry-run"])
@@ -548,7 +705,7 @@ def test_dry_run_with_tag_skips_network(self, uv_tool_argv0, clean_environ):
         # --dry-run with --tag must NOT hit the network.
         with patch("specify_cli.authentication.http.urllib.request.urlopen") as mock_urlopen, patch(
             "specify_cli._version.subprocess.run"
-        ), patch("specify_cli._version.shutil.which", return_value="uv"), patch(
+        ), patch("specify_cli._version.shutil.which", return_value=sys.executable), patch(
             "specify_cli._version._get_installed_version", return_value="0.7.5"
         ):
             result = runner.invoke(
@@ -565,7 +722,7 @@ def test_dry_run_rejects_unparseable_network_tag_before_preview(
         with patch("specify_cli.authentication.http.urllib.request.urlopen") as mock_urlopen, patch(
             "specify_cli._version.subprocess.run"
         ) as mock_run, patch(
-            "specify_cli._version.shutil.which", return_value="uv"
+            "specify_cli._version.shutil.which", return_value=sys.executable
         ), patch("specify_cli._version._get_installed_version", return_value="0.7.5"):
             mock_urlopen.return_value = mock_urlopen_response(
                 {"tag_name": "v0.9.0;echo unsafe"}
@@ -618,10 +775,10 @@ def test_tier3_pipx_when_no_prefix_match_but_registry_lists_it(
         monkeypatch.setattr("sys.argv", [str(tmp_path / "missing" / "specify")])
 
         def fake_which(name):
-            return "pipx" if name == "pipx" else None
+            return sys.executable if name == "pipx" else None
 
         def fake_run(argv, *args, **kwargs):
-            if argv[:3] == ["pipx", "list", "--json"]:
+            if argv[:3] == [sys.executable, "list", "--json"]:
                 return subprocess.CompletedProcess(
                     args=argv,
                     returncode=0,
@@ -645,10 +802,10 @@ def test_tier3_pipx_does_not_override_absolute_unsupported_entrypoint(
         unsupported_argv0,
     ):
         def fake_which(name):
-            return "pipx" if name == "pipx" else None
+            return sys.executable if name == "pipx" else None
 
         def fake_run(argv, *args, **kwargs):
-            if argv[:3] == ["pipx", "list", "--json"]:
+            if argv[:3] == [sys.executable, "list", "--json"]:
                 return subprocess.CompletedProcess(
                     args=argv,
                     returncode=0,
@@ -670,10 +827,10 @@ def test_tier3_pipx_ignores_malformed_json_output(
         unsupported_argv0,
     ):
         def fake_which(name):
-            return "pipx" if name == "pipx" else None
+            return sys.executable if name == "pipx" else None
 
         def fake_run(argv, *args, **kwargs):
-            if argv[:3] == ["pipx", "list", "--json"]:
+            if argv[:3] == [sys.executable, "list", "--json"]:
                 return subprocess.CompletedProcess(
                     args=argv,
                     returncode=0,
@@ -699,20 +856,20 @@ def test_tier3_both_uv_tool_and_pipx_match_is_treated_as_unsupported(
 
         def fake_which(name):
             if name == "uv":
-                return "uv"
+                return sys.executable
             if name == "pipx":
-                return "pipx"
+                return sys.executable
             return None
 
         def fake_run(argv, *args, **kwargs):
-            if argv[:3] == ["uv", "tool", "list"]:
+            if argv[:3] == [sys.executable, "tool", "list"]:
                 return subprocess.CompletedProcess(
                     args=argv,
                     returncode=0,
                     stdout="specify-cli v0.7.6\n",
                     stderr="",
                 )
-            if argv[:3] == ["pipx", "list", "--json"]:
+            if argv[:3] == [sys.executable, "list", "--json"]:
                 return subprocess.CompletedProcess(
                     args=argv,
                     returncode=0,
@@ -801,7 +958,7 @@ def locate_file(self, file):
 class TestTagValidationWhitespace:
     def test_tag_whitespace_is_trimmed_before_validation(self, uv_tool_argv0, clean_environ):
         with patch("specify_cli.authentication.http.urllib.request.urlopen") as mock_urlopen, patch(
-            "specify_cli._version.shutil.which", return_value="uv"
+            "specify_cli._version.shutil.which", return_value=sys.executable
         ), patch("specify_cli._version.subprocess.run") as mock_run, patch(
             "specify_cli._version._get_installed_version", return_value="0.7.5"
         ):
@@ -820,10 +977,10 @@ class TestArgvAssemblyPipx:
     """pipx installer argv shape — pipx 1.5+ uses positional PACKAGE_SPEC, never `--spec` or `upgrade`."""
 
     def test_pipx_argv_uses_install_force_positional_not_upgrade(self):
-        with patch("specify_cli._version.shutil.which", return_value="pipx"):
+        with patch("specify_cli._version.shutil.which", return_value=sys.executable):
             argv = _assemble_installer_argv(_InstallMethod.PIPX, "v0.7.6")
         assert argv == [
-            "pipx",
+            sys.executable,
             "install",
             "--force",
             "git+https://github.com/github/spec-kit.git@v0.7.6",
@@ -841,7 +998,7 @@ class TestBareUpgradePipx:
 
     def test_happy_path(self, pipx_argv0, clean_environ):
         with patch("specify_cli.authentication.http.urllib.request.urlopen") as mock_urlopen, patch(
-            "specify_cli._version.shutil.which", return_value="pipx"
+            "specify_cli._version.shutil.which", return_value=sys.executable
         ), patch("specify_cli._version.subprocess.run") as mock_run, patch(
             "specify_cli._version._get_installed_version", return_value="0.7.5"
         ):
@@ -877,7 +1034,7 @@ def test_pipx_argv0_prefix_short_circuits_before_registry_checks(
 class TestDryRunPipx:
     def test_dry_run_preview_names_pipx(self, pipx_argv0, clean_environ):
         with patch("specify_cli.authentication.http.urllib.request.urlopen") as mock_urlopen, patch(
-            "specify_cli._version.shutil.which", return_value="pipx"
+            "specify_cli._version.shutil.which", return_value=sys.executable
         ), patch("specify_cli._version.subprocess.run") as mock_run, patch(
             "specify_cli._version._get_installed_version", return_value="0.7.5"
         ):
diff --git a/tests/specify_cli/test_version_execution.py b/tests/specify_cli/test_version_execution.py
index 9e3f2514fe..de884e5c5b 100644
--- a/tests/specify_cli/test_version_execution.py
+++ b/tests/specify_cli/test_version_execution.py
@@ -2,6 +2,7 @@
 
 import errno
 import subprocess
+import sys
 from unittest.mock import patch
 
 from specify_cli import app
@@ -234,7 +235,7 @@ def test_real_installer_exit_126_is_not_treated_as_invalid_path(
         self, uv_tool_argv0, clean_environ
     ):
         with patch("specify_cli.authentication.http.urllib.request.urlopen") as mock_urlopen, patch(
-            "specify_cli._version.shutil.which", return_value="uv"
+            "specify_cli._version.shutil.which", return_value=sys.executable
         ), patch("specify_cli._version.subprocess.run") as mock_run, patch(
             "specify_cli._version._get_installed_version", return_value="0.7.5"
         ):
@@ -310,7 +311,7 @@ def test_bare_invalid_installer_message_does_not_call_it_a_path(
         self, uv_tool_argv0, clean_environ
     ):
         with patch("specify_cli.authentication.http.urllib.request.urlopen") as mock_urlopen, patch(
-            "specify_cli._version.shutil.which", return_value="uv"
+            "specify_cli._version.shutil.which", return_value=sys.executable
         ), patch("specify_cli._version._get_installed_version", return_value="0.7.5"), patch(
             "specify_cli._version._assemble_installer_argv",
             return_value=[
@@ -399,7 +400,7 @@ class TestInstallerFailed:
 
     def test_installer_exit_2_propagates(self, uv_tool_argv0, clean_environ):
         with patch("specify_cli.authentication.http.urllib.request.urlopen") as mock_urlopen, patch(
-            "specify_cli._version.shutil.which", return_value="uv"
+            "specify_cli._version.shutil.which", return_value=sys.executable
         ), patch("specify_cli._version.subprocess.run") as mock_run, patch(
             "specify_cli._version._get_installed_version", return_value="0.7.5"
         ):
@@ -422,7 +423,7 @@ def test_installer_exit_2_propagates(self, uv_tool_argv0, clean_environ):
 
     def test_installer_exit_127_propagates(self, uv_tool_argv0, clean_environ):
         with patch("specify_cli.authentication.http.urllib.request.urlopen") as mock_urlopen, patch(
-            "specify_cli._version.shutil.which", return_value="uv"
+            "specify_cli._version.shutil.which", return_value=sys.executable
         ), patch("specify_cli._version.subprocess.run") as mock_run, patch(
             "specify_cli._version._get_installed_version", return_value="0.7.5"
         ):
@@ -436,7 +437,7 @@ def test_installer_timeout_prints_timeout_specific_message(
     ):
         monkeypatch.setenv("SPECIFY_UPGRADE_TIMEOUT_SECS", "12")
         with patch("specify_cli.authentication.http.urllib.request.urlopen") as mock_urlopen, patch(
-            "specify_cli._version.shutil.which", return_value="uv"
+            "specify_cli._version.shutil.which", return_value=sys.executable
         ), patch("specify_cli._version.subprocess.run") as mock_run, patch(
             "specify_cli._version._get_installed_version", return_value="0.7.5"
         ):
@@ -455,7 +456,7 @@ def test_non_finite_timeout_warns_and_runs_without_timeout(
     ):
         monkeypatch.setenv("SPECIFY_UPGRADE_TIMEOUT_SECS", "nan")
         with patch("specify_cli.authentication.http.urllib.request.urlopen") as mock_urlopen, patch(
-            "specify_cli._version.shutil.which", return_value="uv"
+            "specify_cli._version.shutil.which", return_value=sys.executable
         ), patch("specify_cli._version.subprocess.run") as mock_run, patch(
             "specify_cli._version._get_installed_version", return_value="0.7.5"
         ):
@@ -476,7 +477,7 @@ def test_real_installer_exit_124_is_not_treated_as_timeout(
         self, uv_tool_argv0, clean_environ
     ):
         with patch("specify_cli.authentication.http.urllib.request.urlopen") as mock_urlopen, patch(
-            "specify_cli._version.shutil.which", return_value="uv"
+            "specify_cli._version.shutil.which", return_value=sys.executable
         ), patch("specify_cli._version.subprocess.run") as mock_run, patch(
             "specify_cli._version._get_installed_version", return_value="0.7.5"
         ):
@@ -490,7 +491,7 @@ def test_real_installer_exit_124_is_not_treated_as_timeout(
 
     def test_pipx_failure_prints_pipx_rollback_hint(self, pipx_argv0, clean_environ):
         with patch("specify_cli.authentication.http.urllib.request.urlopen") as mock_urlopen, patch(
-            "specify_cli._version.shutil.which", return_value="pipx"
+            "specify_cli._version.shutil.which", return_value=sys.executable
         ), patch("specify_cli._version.subprocess.run") as mock_run, patch(
             "specify_cli._version._get_installed_version", return_value="0.7.5"
         ):
@@ -508,7 +509,7 @@ def test_rollback_hint_accepts_normalizable_stable_snapshot(
         self, uv_tool_argv0, clean_environ
     ):
         with patch("specify_cli.authentication.http.urllib.request.urlopen") as mock_urlopen, patch(
-            "specify_cli._version.shutil.which", return_value="uv"
+            "specify_cli._version.shutil.which", return_value=sys.executable
         ), patch("specify_cli._version.subprocess.run") as mock_run, patch(
             "specify_cli._version._get_installed_version", return_value="v0.7.5"
         ):
@@ -528,7 +529,7 @@ def test_prerelease_failure_degrades_rollback_hint_to_releases_page(
         self, uv_tool_argv0, clean_environ
     ):
         with patch("specify_cli.authentication.http.urllib.request.urlopen") as mock_urlopen, patch(
-            "specify_cli._version.shutil.which", return_value="uv"
+            "specify_cli._version.shutil.which", return_value=sys.executable
         ), patch("specify_cli._version.subprocess.run") as mock_run, patch(
             "specify_cli._version._get_installed_version", return_value="1.0.0rc1"
         ):
diff --git a/tests/specify_cli/test_version_verification.py b/tests/specify_cli/test_version_verification.py
index f3311bb23f..b137e9b310 100644
--- a/tests/specify_cli/test_version_verification.py
+++ b/tests/specify_cli/test_version_verification.py
@@ -1,5 +1,6 @@
 """Verification, resolution, and validation tests for `specify self upgrade`."""
 
+import sys
 import urllib.error
 from unittest.mock import patch
 
@@ -34,7 +35,7 @@ def test_installer_ok_but_verify_returns_old_version(
         clean_environ,
     ):
         with patch("specify_cli.authentication.http.urllib.request.urlopen") as mock_urlopen, patch(
-            "specify_cli._version.shutil.which", return_value="uv"
+            "specify_cli._version.shutil.which", return_value=sys.executable
         ), patch("specify_cli._version.subprocess.run") as mock_run, patch(
             "specify_cli._version._get_installed_version", return_value="0.7.5"
         ):
@@ -57,7 +58,7 @@ def test_verify_nonzero_exit_is_not_treated_as_success(
         clean_environ,
     ):
         with patch("specify_cli.authentication.http.urllib.request.urlopen") as mock_urlopen, patch(
-            "specify_cli._version.shutil.which", return_value="uv"
+            "specify_cli._version.shutil.which", return_value=sys.executable
         ), patch("specify_cli._version.subprocess.run") as mock_run, patch(
             "specify_cli._version._get_installed_version", return_value="0.7.5"
         ):
@@ -79,7 +80,7 @@ def test_verify_accepts_pep440_equivalent_rc_version(
         clean_environ,
     ):
         with patch("specify_cli.authentication.http.urllib.request.urlopen") as mock_urlopen, patch(
-            "specify_cli._version.shutil.which", return_value="uv"
+            "specify_cli._version.shutil.which", return_value=sys.executable
         ), patch("specify_cli._version.subprocess.run") as mock_run, patch(
             "specify_cli._version._get_installed_version", return_value="0.9.0"
         ):
@@ -99,7 +100,7 @@ def test_verify_accepts_specify_cli_binary_name_in_version_output(
         clean_environ,
     ):
         with patch("specify_cli.authentication.http.urllib.request.urlopen") as mock_urlopen, patch(
-            "specify_cli._version.shutil.which", return_value="uv"
+            "specify_cli._version.shutil.which", return_value=sys.executable
         ), patch("specify_cli._version.subprocess.run") as mock_run, patch(
             "specify_cli._version._get_installed_version", return_value="0.7.5"
         ):
@@ -119,7 +120,7 @@ def test_verify_accepts_capitalized_binary_name_in_version_output(
         clean_environ,
     ):
         with patch("specify_cli.authentication.http.urllib.request.urlopen") as mock_urlopen, patch(
-            "specify_cli._version.shutil.which", return_value="uv"
+            "specify_cli._version.shutil.which", return_value=sys.executable
         ), patch("specify_cli._version.subprocess.run") as mock_run, patch(
             "specify_cli._version._get_installed_version", return_value="0.7.5"
         ):
@@ -139,7 +140,7 @@ def test_verify_rejects_output_without_parseable_version(
         clean_environ,
     ):
         with patch("specify_cli.authentication.http.urllib.request.urlopen") as mock_urlopen, patch(
-            "specify_cli._version.shutil.which", return_value="uv"
+            "specify_cli._version.shutil.which", return_value=sys.executable
         ), patch("specify_cli._version.subprocess.run") as mock_run, patch(
             "specify_cli._version._get_installed_version", return_value="0.7.5"
         ):
@@ -349,7 +350,7 @@ def test_unparseable_resolved_release_tag_exits_1_without_traceback(
         with patch("specify_cli.authentication.http.urllib.request.urlopen") as mock_urlopen, patch(
             "specify_cli._version.subprocess.run"
         ) as mock_run, patch(
-            "specify_cli._version.shutil.which", return_value="uv"
+            "specify_cli._version.shutil.which", return_value=sys.executable
         ), patch("specify_cli._version._get_installed_version", return_value="0.7.5"):
             mock_urlopen.return_value = mock_urlopen_response({"tag_name": "release-main"})
             result = runner.invoke(app, ["self", "upgrade"])
@@ -371,7 +372,7 @@ def test_unknown_current_renders_literal_in_notice(
         clean_environ,
     ):
         with patch("specify_cli.authentication.http.urllib.request.urlopen") as mock_urlopen, patch(
-            "specify_cli._version.shutil.which", return_value="uv"
+            "specify_cli._version.shutil.which", return_value=sys.executable
         ), patch("specify_cli._version.subprocess.run") as mock_run, patch(
             "specify_cli._version._get_installed_version", return_value="unknown"
         ):
@@ -393,7 +394,7 @@ def test_unknown_current_rollback_hint_degrades(
         clean_environ,
     ):
         with patch("specify_cli.authentication.http.urllib.request.urlopen") as mock_urlopen, patch(
-            "specify_cli._version.shutil.which", return_value="uv"
+            "specify_cli._version.shutil.which", return_value=sys.executable
         ), patch("specify_cli._version.subprocess.run") as mock_run, patch(
             "specify_cli._version._get_installed_version", return_value="unknown"
         ):
@@ -422,7 +423,7 @@ def test_env_passed_to_subprocess_has_no_github_tokens(
         with patch("specify_cli.authentication.http.urllib.request.urlopen") as mock_urlopen, patch(
             "specify_cli.authentication.http.urllib.request.build_opener"
         ) as mock_build_opener, patch(
-            "specify_cli._version.shutil.which", return_value="uv"
+            "specify_cli._version.shutil.which", return_value=sys.executable
         ), patch("specify_cli._version.subprocess.run") as mock_run, patch(
             "specify_cli._version._get_installed_version", return_value="0.7.5"
         ):
@@ -455,7 +456,7 @@ def test_env_scrubbing_is_case_insensitive(
         with patch("specify_cli.authentication.http.urllib.request.urlopen") as mock_urlopen, patch(
             "specify_cli.authentication.http.urllib.request.build_opener"
         ) as mock_build_opener, patch(
-            "specify_cli._version.shutil.which", return_value="uv"
+            "specify_cli._version.shutil.which", return_value=sys.executable
         ), patch("specify_cli._version.subprocess.run") as mock_run, patch(
             "specify_cli._version._get_installed_version", return_value="0.7.5"
         ):

From 8970a7036d4daa7093fb1e2eef5ff817f3124690 Mon Sep 17 00:00:00 2001
From: Manfred Riem <15701806+mnriem@users.noreply.github.com>
Date: Thu, 29 Oct 2026 07:42:46 -0500
Subject: [PATCH 2/4] fix: close installer path bypasses and preserve rejection
 guidance

Compare both lookup and resolved target directories by filesystem identity, rejecting path-validation errors. Preserve rejection details for registry probes, upgrades, and dry runs without masking unrelated missing installers.

Assisted-by: GitHub Copilot (model: GPT-6.1 Sol, autonomous)
Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
---
 src/specify_cli/_version.py                   |  97 ++++++++++--
 src/specify_cli/selfs/command_upgrade.py      |  16 +-
 .../specify_cli/selfs/test_command_upgrade.py | 116 ++++++++++++++-
 tests/specify_cli/test_version_detection.py   | 139 ++++++++++++++++--
 4 files changed, 330 insertions(+), 38 deletions(-)

diff --git a/src/specify_cli/_version.py b/src/specify_cli/_version.py
index 2dedbe7c93..3ca8ffe474 100644
--- a/src/specify_cli/_version.py
+++ b/src/specify_cli/_version.py
@@ -25,6 +25,7 @@
 from dataclasses import dataclass
 from enum import Enum
 from pathlib import Path
+from typing import Literal, overload
 
 import typer
 from packaging.version import InvalidVersion, Version
@@ -226,6 +227,10 @@ class _InstallerResult:
     returncode: int | None = None
 
 
+class _InstallerRejected(ValueError):
+    """Installer lookup succeeded but its path could not be trusted."""
+
+
 @dataclass(frozen=True)
 class _UpgradePlan:
     """Resolved upgrade decision shared by preview and apply paths."""
@@ -236,6 +241,8 @@ class _UpgradePlan:
     installer_argv: list[str] | None
     preview_summary: str
     pre_upgrade_snapshot: str
+    installer_rejections: tuple[str, ...] = ()
+    installer_rejected: bool = False
 
 
 @dataclass(frozen=True)
@@ -248,6 +255,7 @@ class _DetectionSignals:
     editable_marker_seen: bool
     installer_registries_consulted: tuple[str, ...]
     resolved_method: _InstallMethod
+    installer_rejections: tuple[str, ...] = ()
 
 
 _GITHUB_CREDENTIAL_SUFFIXES = (
@@ -479,17 +487,58 @@ def _editable_marker_seen() -> bool:
 
 def _find_installer(name: str) -> str | None:
     """Resolve an installer without trusting working-directory executables."""
-    resolved = shutil.which(name)
-    if resolved is None:
-        return None
-    installer = Path(resolved)
-    # Windows lookup may prepend cwd even when PATH contains only absolute
-    # directories. Never absolutize that result or fall back to a bare command.
-    if not installer.is_absolute() or installer.resolve().parent == Path.cwd().resolve():
-        return None
+    try:
+        resolved = shutil.which(name)
+        if resolved is None:
+            return None
+        installer = Path(resolved)
+        # Windows lookup may prepend cwd even when PATH is absolute. Check
+        # both the lookup entry and symlink target using filesystem identity.
+        if not installer.is_absolute():
+            raise _InstallerRejected(
+                f"Installer {name} rejected: lookup returned a relative path {resolved!r}. "
+                "Use an absolute PATH entry for the installed tool and retry."
+            )
+        cwd = Path.cwd()
+        if (
+            installer.parent.samefile(cwd)
+            or installer.resolve(strict=True).parent.samefile(cwd)
+        ):
+            raise _InstallerRejected(
+                f"Installer {name} rejected: lookup or target is in the current "
+                f"working directory ({resolved!r}). Run from another directory "
+                "and ensure PATH points to the installed tool."
+            )
+    except (OSError, RuntimeError) as exc:
+        raise _InstallerRejected(
+            f"Installer {name} rejected: could not validate its path ({exc}). "
+            "Run from an existing, accessible working directory and check PATH."
+        ) from exc
     return resolved
 
 
+@overload
+def _detect_install_method(
+    argv0: str | None = None,
+    include_signals: Literal[False] = False,
+) -> _InstallMethod: ...
+
+
+@overload
+def _detect_install_method(
+    argv0: str | None = None,
+    *,
+    include_signals: Literal[True],
+) -> tuple[_InstallMethod, _DetectionSignals]: ...
+
+
+@overload
+def _detect_install_method(
+    argv0: str | None = None,
+    include_signals: bool = False,
+) -> _InstallMethod | tuple[_InstallMethod, _DetectionSignals]: ...
+
+
 def _detect_install_method(
     argv0: str | None = None,
     include_signals: bool = False,
@@ -541,9 +590,14 @@ def _detect_install_method(
 
     # --- Tier 3: PATH + registry reconciliation ---
     consulted: list[str] = []
+    rejections: list[str] = []
     if _tier3_registry_lookup_allowed(argv0_path):
         uv_tool_match = False
-        uv_bin = _find_installer("uv")
+        try:
+            uv_bin = _find_installer("uv")
+        except _InstallerRejected as exc:
+            rejections.append(str(exc))
+            uv_bin = None
         if uv_bin is not None:
             consulted.append("uv tool list")
             try:
@@ -563,7 +617,11 @@ def _detect_install_method(
                 pass
 
         pipx_match = False
-        pipx_bin = _find_installer("pipx")
+        try:
+            pipx_bin = _find_installer("pipx")
+        except _InstallerRejected as exc:
+            rejections.append(str(exc))
+            pipx_bin = None
         if pipx_bin is not None:
             consulted.append("pipx list --json")
             try:
@@ -596,6 +654,7 @@ def _detect_install_method(
                     editable_marker_seen=False,
                     installer_registries_consulted=tuple(consulted),
                     resolved_method=method,
+                    installer_rejections=tuple(rejections),
                 )
             return method
 
@@ -609,6 +668,7 @@ def _detect_install_method(
             editable_marker_seen=False,
             installer_registries_consulted=tuple(consulted),
             resolved_method=method,
+            installer_rejections=tuple(rejections),
         )
     return method
 
@@ -706,7 +766,8 @@ def _build_upgrade_plan(
     A valid `target_tag_override` skips network resolution entirely.
     A fetched target tag is validated before installer argv construction.
     """
-    method = _detect_install_method()
+    method, signals = _detect_install_method(include_signals=True)
+    rejections = list(signals.installer_rejections)
 
     if target_tag_override is not None:
         target_tag = target_tag_override
@@ -733,10 +794,18 @@ def _build_upgrade_plan(
         target_tag = None
 
     current = _get_installed_version()
-    argv = _assemble_installer_argv(method, target_tag)
+    installer_rejected = False
+    try:
+        argv = _assemble_installer_argv(method, target_tag)
+    except _InstallerRejected as exc:
+        rejections.append(str(exc))
+        installer_rejected = True
+        argv = None
     if argv is None and method in (_InstallMethod.UV_TOOL, _InstallMethod.PIPX):
         command_preview = (
-            f"(installer {_installer_binary_name(method)} not found on PATH)"
+            "(installer rejected)"
+            if installer_rejected
+            else f"(installer {_installer_binary_name(method)} not found on PATH)"
         )
     else:
         command_preview = (
@@ -757,6 +826,8 @@ def _build_upgrade_plan(
         installer_argv=argv,
         preview_summary=preview,
         pre_upgrade_snapshot=current,
+        installer_rejections=tuple(rejections),
+        installer_rejected=installer_rejected,
     )
     return plan, None
 
diff --git a/src/specify_cli/selfs/command_upgrade.py b/src/specify_cli/selfs/command_upgrade.py
index 1f645c0e45..445ebc1475 100644
--- a/src/specify_cli/selfs/command_upgrade.py
+++ b/src/specify_cli/selfs/command_upgrade.py
@@ -44,7 +44,7 @@ def self_upgrade(
              installer itself exits 2, that installer failure code is
              propagated verbatim
       3      installer binary not found on PATH, or resolved installer path is
-             missing / non-executable
+             rejected / missing / non-executable
       124    internal installer timeout when SPECIFY_UPGRADE_TIMEOUT_SECS is set,
              or a real installer exit code 124 propagated verbatim; scripts
              should treat 124 as ambiguous and inspect the failure message
@@ -99,6 +99,9 @@ def self_upgrade(
         _emit_failure(failure_reason, plan=plan)
         raise typer.Exit(1)
 
+    for rejection in plan.installer_rejections:
+        console.print(rejection, soft_wrap=True, markup=False)
+
     if dry_run:
         if plan.method in (
             _InstallMethod.UVX_EPHEMERAL,
@@ -121,11 +124,12 @@ def self_upgrade(
         raise typer.Exit(0)
 
     if plan.installer_argv is None:
-        _emit_failure(
-            _FAILURE_INSTALLER_MISSING,
-            plan=plan,
-            installer_name=_installer_binary_name(plan.method),
-        )
+        if not plan.installer_rejected:
+            _emit_failure(
+                _FAILURE_INSTALLER_MISSING,
+                plan=plan,
+                installer_name=_installer_binary_name(plan.method),
+            )
         raise typer.Exit(3)
 
     if plan.target_tag is None:
diff --git a/tests/specify_cli/selfs/test_command_upgrade.py b/tests/specify_cli/selfs/test_command_upgrade.py
index 447394f1df..02a1e8c1a3 100644
--- a/tests/specify_cli/selfs/test_command_upgrade.py
+++ b/tests/specify_cli/selfs/test_command_upgrade.py
@@ -1,19 +1,22 @@
 """Command tests for ``specify self upgrade``."""
 
+import subprocess
 import sys
 from unittest.mock import patch
 
 import pytest
 
 from specify_cli import app
-from tests.specify_cli.self_upgrade_helpers import _InstallMethod, runner, strip_ansi
+from tests.specify_cli.self_upgrade_helpers import runner, strip_ansi
 
 
 @pytest.mark.parametrize(("method", "name"), [("uv-tool", "uv"), ("pipx", "pipx")])
 @pytest.mark.parametrize("absolute", [False, True])
+@pytest.mark.parametrize("dry_run", [False, True])
 def test_unsafe_installer_lookup_aborts_without_execution(
-    monkeypatch, tmp_path, method, name, absolute
+    monkeypatch, tmp_path, request, method, name, absolute, dry_run
 ):
+    request.getfixturevalue("uv_tool_argv0" if method == "uv-tool" else "pipx_argv0")
     monkeypatch.chdir(tmp_path)
     decoy = tmp_path / name
     decoy.write_text("decoy; must never be executed\n", encoding="utf-8")
@@ -21,20 +24,117 @@ def test_unsafe_installer_lookup_aborts_without_execution(
     unsafe_path = str(decoy) if absolute else f"./{name}"
 
     with patch(
-        "specify_cli._version._detect_install_method",
-        return_value=_InstallMethod(method),
-    ), patch(
         "specify_cli._version.shutil.which", return_value=unsafe_path
     ), patch(
         "specify_cli._version._get_installed_version", return_value="0.7.5"
     ), patch("specify_cli._version.subprocess.run") as mock_run:
-        result = runner.invoke(app, ["self", "upgrade", "--tag", "v0.7.6"])
+        args = ["self", "upgrade", "--tag", "v0.7.6"]
+        if dry_run:
+            args.append("--dry-run")
+        result = runner.invoke(app, args)
+
+    assert result.exit_code == (0 if dry_run else 3)
+    output = strip_ansi(result.output)
+    assert f"Installer {name} rejected" in output
+    assert "PATH" in output
+    assert ("Run from another directory" if absolute else "absolute PATH") in output
+    assert "reinstall" not in output
+    assert "not found on PATH" not in output
+    mock_run.assert_not_called()
+
+
+@pytest.mark.parametrize("name", ["uv", "pipx"])
+@pytest.mark.parametrize("dry_run", [False, True])
+def test_registry_probe_rejection_guidance_is_preserved(
+    monkeypatch, tmp_path, name, dry_run
+):
+    monkeypatch.setattr("sys.argv", [str(tmp_path / "missing" / "specify")])
+    with patch(
+        "specify_cli._version.shutil.which",
+        side_effect=lambda command: f"./{name}" if command == name else None,
+    ), patch(
+        "specify_cli._version._editable_marker_seen", return_value=False
+    ), patch("specify_cli._version.subprocess.run") as mock_run:
+        args = ["self", "upgrade", "--tag", "v0.7.6"]
+        if dry_run:
+            args.append("--dry-run")
+        result = runner.invoke(app, args)
+
+    assert result.exit_code == 0
+    output = strip_ansi(result.output)
+    assert f"Installer {name} rejected" in output
+    assert "absolute PATH" in output
+    mock_run.assert_not_called()
 
-    assert result.exit_code == 3
-    assert f"Installer {name} not found on PATH" in strip_ansi(result.output)
+
+@pytest.mark.parametrize(("method", "name"), [("uv-tool", "uv"), ("pipx", "pipx")])
+@pytest.mark.parametrize("dry_run", [False, True])
+def test_deleted_working_directory_gets_rejection_guidance(
+    request, method, name, dry_run
+):
+    request.getfixturevalue("uv_tool_argv0" if method == "uv-tool" else "pipx_argv0")
+    with patch(
+        "specify_cli._version.shutil.which", return_value=sys.executable
+    ), patch(
+        "specify_cli._version.Path.cwd",
+        side_effect=FileNotFoundError("working directory was deleted"),
+    ), patch(
+        "specify_cli._version._get_installed_version", return_value="0.7.5"
+    ), patch("specify_cli._version.subprocess.run") as mock_run:
+        args = ["self", "upgrade", "--tag", "v0.7.6"]
+        if dry_run:
+            args.append("--dry-run")
+        result = runner.invoke(app, args)
+
+    assert result.exit_code == (0 if dry_run else 3)
+    output = strip_ansi(result.output)
+    assert f"Installer {name} rejected: could not validate its path" in output
+    assert "working directory was deleted" in output
+    assert "existing, accessible working directory" in output
     mock_run.assert_not_called()
 
 
+@pytest.mark.parametrize("dry_run", [False, True])
+def test_rejected_probe_does_not_hide_a_different_missing_installer(
+    monkeypatch, tmp_path, dry_run
+):
+    monkeypatch.setattr("sys.argv", [str(tmp_path / "missing" / "specify")])
+    pipx_results = iter([sys.executable, None])
+
+    def fake_which(name):
+        if name == "uv":
+            return "./uv"
+        if name == "pipx":
+            return next(pipx_results)
+        return None
+
+    with patch(
+        "specify_cli._version.shutil.which", side_effect=fake_which
+    ), patch(
+        "specify_cli._version._editable_marker_seen", return_value=False
+    ), patch(
+        "specify_cli._version._get_installed_version", return_value="0.7.5"
+    ), patch("specify_cli._version.subprocess.run") as mock_run:
+        mock_run.return_value = subprocess.CompletedProcess(
+            args=[sys.executable, "list", "--json"],
+            returncode=0,
+            stdout='{"venvs":{"specify-cli":{}}}',
+            stderr="",
+        )
+        args = ["self", "upgrade", "--tag", "v0.7.6"]
+        if dry_run:
+            args.append("--dry-run")
+        result = runner.invoke(app, args)
+
+    assert result.exit_code == (0 if dry_run else 3)
+    output = strip_ansi(result.output)
+    assert "Installer uv rejected" in output
+    assert "pipx not found on PATH" in output
+    assert "Installer pipx rejected" not in output
+    assert mock_run.call_count == 1
+    assert mock_run.call_args.args[0] == [sys.executable, "list", "--json"]
+
+
 class TestTagValidation:
     """--tag option parsing and command help."""
 
diff --git a/tests/specify_cli/test_version_detection.py b/tests/specify_cli/test_version_detection.py
index 1d19d3321c..272aed5984 100644
--- a/tests/specify_cli/test_version_detection.py
+++ b/tests/specify_cli/test_version_detection.py
@@ -325,6 +325,110 @@ def test_path_lookup_resolve_oserror_returns_unresolved_lookup_path(self):
 
 
 class TestInstallerResolution:
+    @pytest.mark.skipif(os.name == "nt", reason="requires unprivileged symlinks")
+    @pytest.mark.parametrize(
+        ("method", "name"),
+        [(_InstallMethod.UV_TOOL, "uv"), (_InstallMethod.PIPX, "pipx")],
+    )
+    def test_working_directory_symlink_to_nested_target_is_rejected(
+        self, monkeypatch, tmp_path, method, name
+    ):
+        project = tmp_path / "project"
+        target = project / "scripts" / name
+        target.parent.mkdir(parents=True)
+        target.write_text("decoy; must never be executed\n", encoding="utf-8")
+        target.chmod(0o755)
+        installer = project / name
+        installer.symlink_to(target)
+        monkeypatch.chdir(project)
+
+        with patch(
+            "specify_cli._version.shutil.which", return_value=str(installer)
+        ), pytest.raises(ValueError, match=f"Installer {name} rejected"):
+            _assemble_installer_argv(method, "v0.7.6")
+
+    @pytest.mark.parametrize(
+        ("method", "name"),
+        [(_InstallMethod.UV_TOOL, "uv"), (_InstallMethod.PIPX, "pipx")],
+    )
+    def test_case_alias_of_working_directory_is_rejected(
+        self, monkeypatch, tmp_path, method, name
+    ):
+        project = tmp_path / "Project"
+        project.mkdir()
+        alias = tmp_path / "pROJECT"
+        if not alias.exists():
+            pytest.skip("requires a case-insensitive filesystem")
+        installer = project / name
+        installer.write_text("decoy; must never be executed\n", encoding="utf-8")
+        installer.chmod(0o755)
+        monkeypatch.chdir(project)
+
+        with patch(
+            "specify_cli._version.shutil.which", return_value=str(alias / name)
+        ), pytest.raises(ValueError, match=f"Installer {name} rejected"):
+            _assemble_installer_argv(method, "v0.7.6")
+
+    @pytest.mark.parametrize(
+        ("method", "name"),
+        [(_InstallMethod.UV_TOOL, "uv"), (_InstallMethod.PIPX, "pipx")],
+    )
+    @pytest.mark.parametrize(
+        ("operation", "error"),
+        [
+            ("cwd", FileNotFoundError("working directory was deleted")),
+            ("samefile", PermissionError("cannot stat installer directory")),
+            ("resolve", RuntimeError("symlink loop")),
+        ],
+    )
+    def test_path_comparison_errors_are_rejected(
+        self, tmp_path, method, name, operation, error
+    ):
+        with patch(
+            "specify_cli._version.shutil.which",
+            side_effect=lambda command: sys.executable if command == name else None,
+        ), patch(
+            "specify_cli._version._resolved_argv0_path",
+            return_value=tmp_path / "missing" / "specify",
+        ), patch(
+            "specify_cli._version._expand_prefix", return_value=None
+        ), patch(
+            "specify_cli._version._editable_marker_seen", return_value=False
+        ), patch(
+            "specify_cli._version.subprocess.run"
+        ) as mock_run, patch.object(
+            Path, operation, side_effect=error
+        ):
+            with pytest.raises(ValueError, match=f"Installer {name} rejected"):
+                _assemble_installer_argv(method, "v0.7.6")
+            detected, signals = _detect_install_method(include_signals=True)
+
+        assert detected == _InstallMethod.UNSUPPORTED
+        assert signals.installer_registries_consulted == ()
+        assert len(signals.installer_rejections) == 1
+        assert str(error) in signals.installer_rejections[0]
+        mock_run.assert_not_called()
+
+    @pytest.mark.parametrize(
+        ("method", "name"),
+        [(_InstallMethod.UV_TOOL, "uv"), (_InstallMethod.PIPX, "pipx")],
+    )
+    @pytest.mark.parametrize("target_missing", [False, True])
+    def test_missing_installer_paths_are_rejected(
+        self, monkeypatch, tmp_path, method, name, target_missing
+    ):
+        project = tmp_path / "project"
+        project.mkdir()
+        monkeypatch.chdir(project)
+        directory = tmp_path / "installer-bin"
+        if target_missing:
+            directory.mkdir()
+
+        with patch(
+            "specify_cli._version.shutil.which", return_value=str(directory / name)
+        ), pytest.raises(ValueError, match=f"Installer {name} rejected"):
+            _assemble_installer_argv(method, "v0.7.6")
+
     @pytest.mark.parametrize(
         ("method", "name"),
         [(_InstallMethod.UV_TOOL, "uv"), (_InstallMethod.PIPX, "pipx")],
@@ -355,12 +459,14 @@ def test_unsafe_lookup_result_is_not_used_for_upgrade_or_registry_probe(
         ), patch(
             "specify_cli._version._editable_marker_seen", return_value=False
         ), patch("specify_cli._version.subprocess.run") as mock_run:
-            argv = _assemble_installer_argv(method, "v0.7.6")
+            with pytest.raises(ValueError, match=f"Installer {name} rejected"):
+                _assemble_installer_argv(method, "v0.7.6")
             detected, signals = _detect_install_method(include_signals=True)
 
-        assert argv is None
         assert detected == _InstallMethod.UNSUPPORTED
         assert signals.installer_registries_consulted == ()
+        assert len(signals.installer_rejections) == 1
+        assert f"Installer {name} rejected" in signals.installer_rejections[0]
         mock_run.assert_not_called()
 
     @pytest.mark.parametrize(
@@ -411,7 +517,11 @@ def test_real_lookup_rejects_working_directory_and_relative_path_entries(
         }
         monkeypatch.setenv("PATH", entries[path_entry])
 
-        assert _assemble_installer_argv(method, "v0.7.6") is None
+        if path_entry == "empty":
+            assert _assemble_installer_argv(method, "v0.7.6") is None
+        else:
+            with pytest.raises(ValueError, match=f"Installer {name} rejected"):
+                _assemble_installer_argv(method, "v0.7.6")
 
     @pytest.mark.parametrize(
         ("method", "name"),
@@ -457,27 +567,34 @@ def test_windows_implicit_cwd_lookup_cannot_shadow_installed_tool(
         monkeypatch.setenv("PATHEXT", ".EXE")
         monkeypatch.delenv("NoDefaultCurrentDirectoryInExePath", raising=False)
 
-        argv = _assemble_installer_argv(method, "v0.7.6")
-
-        assert argv is None or Path(argv[0]) == directory / f"{name}.exe"
+        try:
+            argv = _assemble_installer_argv(method, "v0.7.6")
+        except specify_cli._version._InstallerRejected:
+            return
+        assert argv is not None
+        assert Path(argv[0]) == directory / f"{name}.exe"
 
     @pytest.mark.skipif(os.name == "nt", reason="requires unprivileged symlinks")
+    @pytest.mark.parametrize(
+        ("method", "name"),
+        [(_InstallMethod.UV_TOOL, "uv"), (_InstallMethod.PIPX, "pipx")],
+    )
     def test_absolute_symlink_to_working_directory_installer_is_rejected(
-        self, monkeypatch, tmp_path
+        self, monkeypatch, tmp_path, method, name
     ):
         project = tmp_path / "project"
         project.mkdir()
         monkeypatch.chdir(project)
-        decoy = project / "uv"
+        decoy = project / name
         decoy.write_text("#!/bin/sh\n", encoding="utf-8")
         decoy.chmod(0o755)
-        installer = tmp_path / "uv"
+        installer = tmp_path / name
         installer.symlink_to(decoy)
 
         with patch(
             "specify_cli._version.shutil.which", return_value=str(installer)
-        ):
-            assert _assemble_installer_argv(_InstallMethod.UV_TOOL, "v0.7.6") is None
+        ), pytest.raises(ValueError, match=f"Installer {name} rejected"):
+            _assemble_installer_argv(method, "v0.7.6")
 
 
 class TestArgvAssemblyUvTool:

From f5c3063378e55148b2968428281a24f4140c404d Mon Sep 17 00:00:00 2001
From: Manfred Riem <15701806+mnriem@users.noreply.github.com>
Date: Thu, 29 Oct 2026 08:33:51 -0500
Subject: [PATCH 3/4] fix: isolate installer decoys and clarify Windows lookup
 guidance

Keep decoy executables in a separate working directory from installer fixtures and exercise the Windows directory layout on all platforms. Explain how to avoid implicit current-directory matches when installer lookup returns a relative path.

Assisted-by: GitHub Copilot (model: GPT-6.1 Sol, autonomous)
Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
---
 src/specify_cli/_version.py                     |  4 +++-
 tests/specify_cli/selfs/test_command_upgrade.py | 11 +++++++++--
 tests/specify_cli/test_version_detection.py     |  6 +++++-
 3 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/src/specify_cli/_version.py b/src/specify_cli/_version.py
index 3ca8ffe474..8157572a39 100644
--- a/src/specify_cli/_version.py
+++ b/src/specify_cli/_version.py
@@ -497,7 +497,9 @@ def _find_installer(name: str) -> str | None:
         if not installer.is_absolute():
             raise _InstallerRejected(
                 f"Installer {name} rejected: lookup returned a relative path {resolved!r}. "
-                "Use an absolute PATH entry for the installed tool and retry."
+                "Use an absolute PATH entry for the installed tool. "
+                "Run from a directory without a matching installer executable "
+                "to avoid implicit current-directory matches on Windows, and retry."
             )
         cwd = Path.cwd()
         if (
diff --git a/tests/specify_cli/selfs/test_command_upgrade.py b/tests/specify_cli/selfs/test_command_upgrade.py
index 02a1e8c1a3..f986aa00c4 100644
--- a/tests/specify_cli/selfs/test_command_upgrade.py
+++ b/tests/specify_cli/selfs/test_command_upgrade.py
@@ -17,8 +17,12 @@ def test_unsafe_installer_lookup_aborts_without_execution(
     monkeypatch, tmp_path, request, method, name, absolute, dry_run
 ):
     request.getfixturevalue("uv_tool_argv0" if method == "uv-tool" else "pipx_argv0")
-    monkeypatch.chdir(tmp_path)
-    decoy = tmp_path / name
+    # Exercise the Windows fixture directory collision on every platform.
+    (tmp_path / name).mkdir(exist_ok=True)
+    project = tmp_path / "project"
+    project.mkdir()
+    monkeypatch.chdir(project)
+    decoy = project / name
     decoy.write_text("decoy; must never be executed\n", encoding="utf-8")
     decoy.chmod(0o755)
     unsafe_path = str(decoy) if absolute else f"./{name}"
@@ -38,6 +42,8 @@ def test_unsafe_installer_lookup_aborts_without_execution(
     assert f"Installer {name} rejected" in output
     assert "PATH" in output
     assert ("Run from another directory" if absolute else "absolute PATH") in output
+    if not absolute:
+        assert "Run from a directory without a matching installer executable" in output
     assert "reinstall" not in output
     assert "not found on PATH" not in output
     mock_run.assert_not_called()
@@ -64,6 +70,7 @@ def test_registry_probe_rejection_guidance_is_preserved(
     output = strip_ansi(result.output)
     assert f"Installer {name} rejected" in output
     assert "absolute PATH" in output
+    assert "Run from a directory without a matching installer executable" in output
     mock_run.assert_not_called()
 
 
diff --git a/tests/specify_cli/test_version_detection.py b/tests/specify_cli/test_version_detection.py
index 272aed5984..4a3cdf258a 100644
--- a/tests/specify_cli/test_version_detection.py
+++ b/tests/specify_cli/test_version_detection.py
@@ -459,7 +459,7 @@ def test_unsafe_lookup_result_is_not_used_for_upgrade_or_registry_probe(
         ), patch(
             "specify_cli._version._editable_marker_seen", return_value=False
         ), patch("specify_cli._version.subprocess.run") as mock_run:
-            with pytest.raises(ValueError, match=f"Installer {name} rejected"):
+            with pytest.raises(ValueError, match=f"Installer {name} rejected") as rejection:
                 _assemble_installer_argv(method, "v0.7.6")
             detected, signals = _detect_install_method(include_signals=True)
 
@@ -467,6 +467,10 @@ def test_unsafe_lookup_result_is_not_used_for_upgrade_or_registry_probe(
         assert signals.installer_registries_consulted == ()
         assert len(signals.installer_rejections) == 1
         assert f"Installer {name} rejected" in signals.installer_rejections[0]
+        if location == "windows-relative":
+            guidance = "Run from a directory without a matching installer executable"
+            assert guidance in str(rejection.value)
+            assert guidance in signals.installer_rejections[0]
         mock_run.assert_not_called()
 
     @pytest.mark.parametrize(

From 8b85bf7e94e68132738a13c5d24a218326cbbc68 Mon Sep 17 00:00:00 2001
From: Manfred Riem <15701806+mnriem@users.noreply.github.com>
Date: Thu, 29 Oct 2026 09:01:34 -0500
Subject: [PATCH 4/4] fix: reject installer ownership when a registry probe is
 unsafe

Treat rejected Tier-3 probes as unresolved ownership rather than selecting the other installer. Cover both installer directions and normal/dry-run CLI behavior without invoking an upgrade.

Assisted-by: GitHub Copilot (model: GPT-6.1 Sol, autonomous)
Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
---
 src/specify_cli/_version.py                   |  6 +--
 .../specify_cli/selfs/test_command_upgrade.py | 34 +++++++++-------
 tests/specify_cli/test_version_detection.py   | 40 +++++++++++++++++++
 3 files changed, 63 insertions(+), 17 deletions(-)

diff --git a/src/specify_cli/_version.py b/src/specify_cli/_version.py
index 951be08897..bcfe42caa6 100644
--- a/src/specify_cli/_version.py
+++ b/src/specify_cli/_version.py
@@ -647,10 +647,10 @@ def _detect_install_method(
             except (subprocess.TimeoutExpired, OSError, ValueError):
                 pass
 
-        # If both registries claim ownership, the active entrypoint is ambiguous.
-        # Treat it as unsupported rather than guessing and upgrading the wrong install.
+        # Both matches or a rejected probe leave ownership ambiguous.
+        # Never guess and risk upgrading the wrong installation.
         exactly_one_match = uv_tool_match != pipx_match
-        if exactly_one_match:
+        if exactly_one_match and not rejections:
             method = _InstallMethod.UV_TOOL if uv_tool_match else _InstallMethod.PIPX
             if include_signals:
                 return method, _DetectionSignals(
diff --git a/tests/specify_cli/selfs/test_command_upgrade.py b/tests/specify_cli/selfs/test_command_upgrade.py
index f986aa00c4..cfb03d640b 100644
--- a/tests/specify_cli/selfs/test_command_upgrade.py
+++ b/tests/specify_cli/selfs/test_command_upgrade.py
@@ -102,17 +102,22 @@ def test_deleted_working_directory_gets_rejection_guidance(
 
 
 @pytest.mark.parametrize("dry_run", [False, True])
-def test_rejected_probe_does_not_hide_a_different_missing_installer(
-    monkeypatch, tmp_path, dry_run
+@pytest.mark.parametrize("rejected_name", ["uv", "pipx"])
+def test_rejected_probe_prevents_selecting_a_different_installer(
+    monkeypatch, tmp_path, dry_run, rejected_name
 ):
     monkeypatch.setattr("sys.argv", [str(tmp_path / "missing" / "specify")])
-    pipx_results = iter([sys.executable, None])
+    other_name = "pipx" if rejected_name == "uv" else "uv"
+    probe_args = ["list", "--json"] if other_name == "pipx" else ["tool", "list"]
+    probe_output = (
+        '{"venvs":{"specify-cli":{}}}' if other_name == "pipx" else "specify-cli v0.7.6\n"
+    )
 
     def fake_which(name):
-        if name == "uv":
-            return "./uv"
-        if name == "pipx":
-            return next(pipx_results)
+        if name == rejected_name:
+            return f"./{name}"
+        if name == other_name:
+            return sys.executable
         return None
 
     with patch(
@@ -123,9 +128,9 @@ def fake_which(name):
         "specify_cli._version._get_installed_version", return_value="0.7.5"
     ), patch("specify_cli._version.subprocess.run") as mock_run:
         mock_run.return_value = subprocess.CompletedProcess(
-            args=[sys.executable, "list", "--json"],
+            args=[sys.executable, *probe_args],
             returncode=0,
-            stdout='{"venvs":{"specify-cli":{}}}',
+            stdout=probe_output,
             stderr="",
         )
         args = ["self", "upgrade", "--tag", "v0.7.6"]
@@ -133,13 +138,14 @@ def fake_which(name):
             args.append("--dry-run")
         result = runner.invoke(app, args)
 
-    assert result.exit_code == (0 if dry_run else 3)
+    assert result.exit_code == 0
     output = strip_ansi(result.output)
-    assert "Installer uv rejected" in output
-    assert "pipx not found on PATH" in output
-    assert "Installer pipx rejected" not in output
+    assert f"Installer {rejected_name} rejected" in output
+    assert "Could not identify your install method automatically" in output
+    assert "Upgrading specify-cli" not in output
+    assert "not found on PATH" not in output
     assert mock_run.call_count == 1
-    assert mock_run.call_args.args[0] == [sys.executable, "list", "--json"]
+    assert mock_run.call_args.args[0] == [sys.executable, *probe_args]
 
 
 class TestTagValidation:
diff --git a/tests/specify_cli/test_version_detection.py b/tests/specify_cli/test_version_detection.py
index 4a3cdf258a..8235995b12 100644
--- a/tests/specify_cli/test_version_detection.py
+++ b/tests/specify_cli/test_version_detection.py
@@ -1011,6 +1011,46 @@ def fake_run(argv, *args, **kwargs):
         assert "pipx list --json" in signals.installer_registries_consulted
 
 
+    @pytest.mark.parametrize("rejected_name", ["uv", "pipx"])
+    def test_tier3_rejected_probe_leaves_ownership_ambiguous(
+        self, monkeypatch, tmp_path, rejected_name
+    ):
+        monkeypatch.setattr("sys.argv", [str(tmp_path / "missing" / "specify")])
+        other_name = "pipx" if rejected_name == "uv" else "uv"
+        probe_args = ["list", "--json"] if other_name == "pipx" else ["tool", "list"]
+        probe_output = (
+            '{"venvs":{"specify-cli":{}}}' if other_name == "pipx" else "specify-cli v0.7.6\n"
+        )
+
+        def fake_which(name):
+            if name == rejected_name:
+                return f"./{name}"
+            if name == other_name:
+                return sys.executable
+            return None
+
+        with patch(
+            "specify_cli._version.shutil.which", side_effect=fake_which
+        ), patch(
+            "specify_cli._version._editable_marker_seen", return_value=False
+        ), patch("specify_cli._version.subprocess.run") as mock_run:
+            mock_run.return_value = subprocess.CompletedProcess(
+                args=[sys.executable, *probe_args],
+                returncode=0,
+                stdout=probe_output,
+                stderr="",
+            )
+            method, signals = _detect_install_method(include_signals=True)
+
+        assert method == _InstallMethod.UNSUPPORTED
+        assert signals.matched_tier is None
+        assert signals.installer_registries_consulted == (" ".join([other_name, *probe_args]),)
+        assert len(signals.installer_rejections) == 1
+        assert f"Installer {rejected_name} rejected" in signals.installer_rejections[0]
+        mock_run.assert_called_once()
+        assert mock_run.call_args.args[0] == [sys.executable, *probe_args]
+
+
 class TestEditableInstallMetadata:
     @pytest.mark.skipif(
         not hasattr(importlib.metadata, "InvalidMetadataError"),