Fetching: git on Mac OS (#24247)

Extend the changes in #24163 to unit tests.

3 files changed, 15 insertions, 5 deletions

diff --git a/lib/spack/spack/fetch_strategy.py b/lib/spack/spack/fetch_strategy.py
index da0b12556f..b4ca8b3e70 100644
--- a/lib/spack/spack/fetch_strategy.py
+++ b/lib/spack/spack/fetch_strategy.py
@@ -766,6 +766,8 @@ class GitFetchStrategy(VCSFetchStrategy):
     optional_attrs = ['tag', 'branch', 'commit', 'submodules',
                       'get_full_repo', 'submodules_delete']
 
+    git_version_re = r'git version (\S+)'
+
     def __init__(self, **kwargs):
         # Discards the keywords in kwargs that may conflict with the next call
         # to __init__
@@ -780,9 +782,16 @@ class GitFetchStrategy(VCSFetchStrategy):
 
     @property
     def git_version(self):
-        output = self.git('--version', output=str, error=str)
-        match = re.search(r'git version (\S+)', output)
-        return Version(match.group(1)) if match else None
+        return GitFetchStrategy.version_from_git(self.git)
+
+    @staticmethod
+    def version_from_git(git_exe):
+        """Given a git executable, return the Version (this will fail if
+           the output cannot be parsed into a valid Version).
+        """
+        version_output = git_exe('--version', output=str)
+        m = re.search(GitFetchStrategy.git_version_re, version_output)
+        return Version(m.group(1))
 
     @property
     def git(self):
diff --git a/lib/spack/spack/test/cmd/is_git_repo.py b/lib/spack/spack/test/cmd/is_git_repo.py
index 109f5030c7..fcfd1e010d 100644
--- a/lib/spack/spack/test/cmd/is_git_repo.py
+++ b/lib/spack/spack/test/cmd/is_git_repo.py
@@ -28,7 +28,7 @@ def check_git_version():
     Refer:
     https://github.com/git/git/commit/cc73385cf6c5c229458775bc92e7dbbe24d11611
     """
-    git_version = ver(git('--version', output=str).lstrip('git version '))
+    git_version = spack.fetch_strategy.GitFetchStrategy.version_from_git(git)
     return git_version >= ver(git_required_version)
 
 
diff --git a/lib/spack/spack/test/git_fetch.py b/lib/spack/spack/test/git_fetch.py
index ad010e3ca5..e06077df83 100644
--- a/lib/spack/spack/test/git_fetch.py
+++ b/lib/spack/spack/test/git_fetch.py
@@ -37,7 +37,8 @@ def git_version(request, monkeypatch):
     use the backward-compatibility code paths with newer git versions.
     """
     git = which('git', required=True)
-    real_git_version = ver(git('--version', output=str).lstrip('git version '))
+    real_git_version = (
+        spack.fetch_strategy.GitFetchStrategy.version_from_git(git))
 
     if request.param is None:
         # Don't patch; run with the real git_version method.