diff --git a/lib/spack/spack/solver/asp.py b/lib/spack/spack/solver/asp.py
index 8a0a8a906e4..6f92ab0b122 100644
--- a/lib/spack/spack/solver/asp.py
+++ b/lib/spack/spack/solver/asp.py
@@ -4207,8 +4207,7 @@ def _specs_with_commits(spec):
             " does not meet commit syntax requirements."
         )
 
-        # TODO probably want a more specific function just for sha validation
-        assert vn.is_git_version(spec.variants["commit"].value), invalid_commit_msg
+        assert vn.is_git_commit_sha(spec.variants["commit"].value), invalid_commit_msg
 
     # Specs with GitVersions
     # - must have a commit variant, or add it here
diff --git a/lib/spack/spack/version/__init__.py b/lib/spack/spack/version/__init__.py
index 42f15fffcce..357add8c476 100644
--- a/lib/spack/spack/version/__init__.py
+++ b/lib/spack/spack/version/__init__.py
@@ -20,6 +20,7 @@
     VersionError,
     VersionLookupError,
     infinity_versions,
+    is_git_commit_sha,
     is_git_version,
 )
 from .version_types import (
@@ -58,6 +59,7 @@
     "any_version",
     "from_string",
     "infinity_versions",
+    "is_git_commit_sha",
     "is_git_version",
     "ver",
 ]
diff --git a/lib/spack/spack/version/common.py b/lib/spack/spack/version/common.py
index 7cac90ca86b..60f06d6575f 100644
--- a/lib/spack/spack/version/common.py
+++ b/lib/spack/spack/version/common.py
@@ -23,11 +23,14 @@
 STRING_TO_PRERELEASE = {"alpha": ALPHA, "beta": BETA, "rc": RC, "final": FINAL}
 
 
+def is_git_commit_sha(string: str) -> bool:
+    return len(string) == 40 and bool(COMMIT_VERSION.match(string))
+
+
 def is_git_version(string: str) -> bool:
     return (
         string.startswith("git.")
-        or len(string) == 40
-        and bool(COMMIT_VERSION.match(string))
+        or is_git_commit_sha(string)
         or "=" in string[1:]
     )