🐛 fix(discovery): don't probe PATH directories as interpreters

docs/changelog/+skip-path-dir-probe.bugfix.rst

@@ -0,0 +1,2 @@
+:func:`~python_discovery.iter_interpreters` with no key no longer probes ``PATH`` directories or subdirectories named
+like Python executables as interpreters.

src/python_discovery/_discovery.py

@@ -496,12 +496,13 @@ def path_exe_finder(
         direct = f"{direct}.exe"
 
     def path_exes(path: Path) -> Generator[tuple[Path, bool], None, None]:
+        # an empty spec (enumerating everything) would make the direct path the PATH directory itself
         direct_path = path / direct
-        if direct_path.exists():
+        if direct_path.is_file():
             yield direct_path, impl_must_match
 
         for exe in path.iterdir():
-            if match := pat.fullmatch(exe.name):
+            if (match := pat.fullmatch(exe.name)) and exe.is_file():
                 yield exe.absolute(), impl_must_match or match["impl"].lower() == "python"
 
     return path_exes

tests/test_iter_interpreters.py

@@ -144,6 +144,30 @@ def test_iter_interpreters_no_key_probes_variant_builds_on_path(
     assert str(exe) in [call.args[0] for call in from_exe.call_args_list]
 
 
+@pytest.mark.usefixtures("uv_dir")
+@pytest.mark.parametrize(
+    "directory_name",
+    [
+        pytest.param(".", id="path-directory"),
+        pytest.param(f"python3.99{'.exe' if IS_WIN else ''}", id="named-directory"),
+    ],
+)
+def test_iter_interpreters_skips_path_directories(
+    tmp_path: Path, monkeypatch: pytest.MonkeyPatch, mocker: MockerFixture, directory_name: str
+) -> None:
+    bin_dir = tmp_path / "bin"
+    bin_dir.mkdir()
+    (bin_dir / directory_name).mkdir(exist_ok=True)
+    executable = bin_dir / f"python3.98{'.exe' if IS_WIN else ''}"
+    executable.touch()
+    monkeypatch.setenv("PATH", str(bin_dir))
+    from_exe = mocker.patch("python_discovery._discovery.PathPythonInfo.from_exe", return_value=None)
+
+    list(iter_interpreters())
+
+    assert [call.args[0] for call in from_exe.call_args_list] == [str(executable)]
+
+
 @pytest.mark.usefixtures("uv_dir")
 def test_iter_interpreters_dedups_symlinks(
     tmp_path: Path,