Get git executable for collections in git repos (#77493)

* Fix traceback installing collections from git repos if git is not installed

changelogs/fragments/77493-ansible-galaxy-find-git-executable-before-using.yaml

@@ -0,0 +1,2 @@
+bugfixes:
+  - Fix traceback when installing a collection from a git repository and git is not installed (https://github.com/ansible/ansible/issues/77479).

lib/ansible/galaxy/collection/concrete_artifact_manager.py

@@ -30,6 +30,7 @@ from ansible.galaxy import get_collections_galaxy_meta_info
 from ansible.galaxy.dependency_resolution.dataclasses import _GALAXY_YAML
 from ansible.galaxy.user_agent import user_agent
 from ansible.module_utils._text import to_bytes, to_native, to_text
+from ansible.module_utils.common.process import get_bin_path
 from ansible.module_utils.common.yaml import yaml_load
 from ansible.module_utils.six import raise_from
 from ansible.module_utils.urls import open_url
@@ -393,11 +394,19 @@ def _extract_collection_from_git(repo_url, coll_ver, b_path):
         prefix=to_bytes(name, errors='surrogate_or_strict'),
     )  # type: bytes
 
+    try:
+        git_executable = get_bin_path('git')
+    except ValueError as err:
+        raise AnsibleError(
+            "Could not find git executable to extract the collection from the Git repository `{repo_url!s}`.".
+            format(repo_url=to_native(git_url))
+        ) from err
+
     # Perform a shallow clone if simply cloning HEAD
     if version == 'HEAD':
-        git_clone_cmd = 'git', 'clone', '--depth=1', git_url, to_text(b_checkout_path)
+        git_clone_cmd = git_executable, 'clone', '--depth=1', git_url, to_text(b_checkout_path)
     else:
-        git_clone_cmd = 'git', 'clone', git_url, to_text(b_checkout_path)
+        git_clone_cmd = git_executable, 'clone', git_url, to_text(b_checkout_path)
     # FIXME: '--branch', version
 
     try:
@@ -411,7 +420,7 @@ def _extract_collection_from_git(repo_url, coll_ver, b_path):
             proc_err,
         )
 
-    git_switch_cmd = 'git', 'checkout', to_text(version)
+    git_switch_cmd = git_executable, 'checkout', to_text(version)
     try:
         subprocess.check_call(git_switch_cmd, cwd=b_checkout_path)
     except subprocess.CalledProcessError as proc_err:

test/units/galaxy/test_collection_install.py

@@ -18,6 +18,7 @@ import yaml
 
 from io import BytesIO, StringIO
 from mock import MagicMock, patch
+from unittest import mock
 
 import ansible.module_utils.six.moves.urllib.error as urllib_error
 
@@ -27,6 +28,7 @@ from ansible.errors import AnsibleError
 from ansible.galaxy import collection, api, dependency_resolution
 from ansible.galaxy.dependency_resolution.dataclasses import Candidate, Requirement
 from ansible.module_utils._text import to_bytes, to_native, to_text
+from ansible.module_utils.common.process import get_bin_path
 from ansible.utils import context_objects as co
 from ansible.utils.display import Display
 
@@ -172,6 +174,22 @@ def galaxy_server():
     return galaxy_api
 
 
+def test_concrete_artifact_manager_scm_no_executable(monkeypatch):
+    url = 'https://github.com/org/repo'
+    version = 'commitish'
+    mock_subprocess_check_call = MagicMock()
+    monkeypatch.setattr(collection.concrete_artifact_manager.subprocess, 'check_call', mock_subprocess_check_call)
+    mock_mkdtemp = MagicMock(return_value='')
+    monkeypatch.setattr(collection.concrete_artifact_manager, 'mkdtemp', mock_mkdtemp)
+
+    error = re.escape(
+        "Could not find git executable to extract the collection from the Git repository `https://github.com/org/repo`"
+    )
+    with mock.patch.dict(os.environ, {"PATH": ""}):
+        with pytest.raises(AnsibleError, match=error):
+            collection.concrete_artifact_manager._extract_collection_from_git(url, version, b'path')
+
+
 @pytest.mark.parametrize(
     'url,version,trailing_slash',
     [
@@ -194,10 +212,12 @@ def test_concrete_artifact_manager_scm_cmd(url, version, trailing_slash, monkeyp
     repo = 'https://github.com/org/repo'
     if trailing_slash:
         repo += '/'
-    clone_cmd = ('git', 'clone', repo, '')
+
+    git_executable = get_bin_path('git')
+    clone_cmd = (git_executable, 'clone', repo, '')
 
     assert mock_subprocess_check_call.call_args_list[0].args[0] == clone_cmd
-    assert mock_subprocess_check_call.call_args_list[1].args[0] == ('git', 'checkout', 'commitish')
+    assert mock_subprocess_check_call.call_args_list[1].args[0] == (git_executable, 'checkout', 'commitish')
 
 
 @pytest.mark.parametrize(
@@ -223,10 +243,11 @@ def test_concrete_artifact_manager_scm_cmd_shallow(url, version, trailing_slash,
     repo = 'https://github.com/org/repo'
     if trailing_slash:
         repo += '/'
-    shallow_clone_cmd = ('git', 'clone', '--depth=1', repo, '')
+    git_executable = get_bin_path('git')
+    shallow_clone_cmd = (git_executable, 'clone', '--depth=1', repo, '')
 
     assert mock_subprocess_check_call.call_args_list[0].args[0] == shallow_clone_cmd
-    assert mock_subprocess_check_call.call_args_list[1].args[0] == ('git', 'checkout', 'HEAD')
+    assert mock_subprocess_check_call.call_args_list[1].args[0] == (git_executable, 'checkout', 'HEAD')
 
 
 def test_build_requirement_from_path(collection_artifact):