Increase min version for sparse_checkout (spack#45818)

* Increase min version for sparse_checkout

* Update git_fetch.py

* style

lib/spack/spack/fetch_strategy.py

@@ -930,7 +930,9 @@ def _sparse_clone_src(self, commit=None, branch=None, tag=None, **kwargs):
         dest = self.stage.source_path
         git = self.git
 
-        if self.git_version < spack.version.Version("2.25.0.0"):
+        if self.git_version < spack.version.Version("2.26.0"):
+            # technically this should be supported for 2.25, but bumping for OS issues
+            # see https://github.com/spack/spack/issues/45771
             # code paths exist where the package is not set.  Assure some indentifier for the
             # package that was configured  for sparse checkout exists in the error message
             identifier = str(self.url)

lib/spack/spack/test/git_fetch.py

@@ -415,7 +415,7 @@ def test_git_sparse_paths_partial_clone(
         for p in sparse_paths:
             assert os.path.isdir(p)
 
-        if git_version < Version("2.25.0.0"):
+        if git_version < Version("2.26.0.0"):
             # older versions of git should fall back to a full clone
             for p in omitted_paths:
                 assert os.path.isdir(p)