bugfix: Also skip gitcache executable named git

CHANGELOG.md

@@ -7,6 +7,10 @@
 - Bugfix: Fetch the LFS objects of a `git checkout` of a tag or a commit as well. Previously, only a checkout of a
   branch triggered an LFS fetch of the mirror and the LFS objects of a tag or commit were downloaded by the git-lfs
   filters of the checkout itself.
+- Bugfix: Skip the gitcache executable itself when searching for the real git command. Previously, only a symlink
+  named `git` was skipped, so that renaming or hard-linking the gitcache executable to `git` resulted in an
+  infinite recursion. As the check now compares the candidates with the gitcache executable, a symlink pointing to
+  the real git command is no longer skipped either.
 
 ## v1.0.34
 

src/git_cache/config.py

@@ -20,6 +20,7 @@
 import os
 import platform
 import re
+import sys
 from typing import Any, Callable, Dict, List, Optional
 
 import pytimeparse
@@ -92,9 +93,11 @@ def find_git() -> str:
         cmd = "git.exe" if on_windows else "git"
         for candidate in path.split(os.path.pathsep):
             candidate = os.path.join(candidate, cmd)
-            if os.path.exists(candidate) and os.access(candidate, os.X_OK):
-                if not os.path.islink(candidate):
-                    return candidate
+            if not os.path.exists(candidate) or not os.access(candidate, os.X_OK):
+                continue
+            if os.path.samefile(candidate, sys.executable):
+                continue
+            return candidate
 
     LOG.warning("Can't find git command! Please specify manually in the config file!")
     return "/usr/bin/git"

test/unittests/test_git_cache_config.py

@@ -13,6 +13,10 @@
 # -----------------------------------------------------------------------------
 import importlib
 import os
+import platform
+import shutil
+import sys
+import tempfile
 from unittest import TestCase
 
 import mock
@@ -157,6 +161,67 @@ def test_str_rep(self):
         self.assertEqual(str(config), expected_config_str)
 
 
+class GitCacheFindGitTest(TestCase):
+    """Test the :func:`git_cache.config.find_git` function."""
+
+    ON_WINDOWS = platform.system().lower().startswith("win")
+    GIT_CMD = "git.exe" if ON_WINDOWS else "git"
+    GITCACHE_CMD = "gitcache.exe" if ON_WINDOWS else "gitcache"
+
+    def setUp(self):
+        """Set up the test case with a gitcache executable and a real git command."""
+        self.tmp_dir = tempfile.mkdtemp()
+        self.gitcache_cmd = self._create_executable(self.tmp_dir, self.GITCACHE_CMD)
+
+        self.real_git_dir = os.path.join(self.tmp_dir, "real")
+        os.makedirs(self.real_git_dir)
+        self.real_git_cmd = self._create_executable(self.real_git_dir, self.GIT_CMD)
+
+        self.gitcache_dir = os.path.join(self.tmp_dir, "gitcache_bin")
+        os.makedirs(self.gitcache_dir)
+
+    def tearDown(self):
+        """Tear down the test case."""
+        shutil.rmtree(self.tmp_dir, ignore_errors=True)
+
+    @staticmethod
+    def _create_executable(directory, name):
+        """Create an executable file and return its path."""
+        path = os.path.join(directory, name)
+        with open(path, "w", encoding="utf-8") as file_handle:
+            file_handle.write("#!/bin/sh\nexit 0\n")
+        os.chmod(path, 0o755)
+        return path
+
+    def _find_git(self, executable):
+        """Call find_git() as the given executable with the gitcache dir in front of the real git dir."""
+        path = os.path.pathsep.join([self.gitcache_dir, self.real_git_dir])
+        with mock.patch.object(sys, "executable", executable), mockenv(PATH=path):
+            return git_cache.config.find_git()
+
+    def test_gitcache_executable(self):
+        """git_cache.config.find_git: Find the real git command."""
+        self.assertEqual(self._find_git(self.gitcache_cmd), self.real_git_cmd)
+
+    def test_skip_git_symlink(self):
+        """git_cache.config.find_git: Skip a symlink to the gitcache executable."""
+        try:
+            os.symlink(self.gitcache_cmd, os.path.join(self.gitcache_dir, self.GIT_CMD))
+        except OSError:
+            self.skipTest("This system does not allow the creation of symlinks.")
+        self.assertEqual(self._find_git(self.gitcache_cmd), self.real_git_cmd)
+
+    def test_skip_git_hardlink(self):
+        """git_cache.config.find_git: Skip a hard link to the gitcache executable."""
+        os.link(self.gitcache_cmd, os.path.join(self.gitcache_dir, self.GIT_CMD))
+        self.assertEqual(self._find_git(self.gitcache_cmd), self.real_git_cmd)
+
+    def test_skip_git_executable(self):
+        """git_cache.config.find_git: Skip the gitcache executable itself named git."""
+        gitcache_as_git = self._create_executable(self.gitcache_dir, self.GIT_CMD)
+        self.assertEqual(self._find_git(gitcache_as_git), self.real_git_cmd)
+
+
 # -----------------------------------------------------------------------------
 # EOF
 # -----------------------------------------------------------------------------