Only check version and date when spec changed

There are now several files in the repository which can be changed
without bumping the version and date in the spec. Update check_release.py
to check whether the spec itself has been altered before checking version
and date have been increased.

Signed-off-by: Joshua Lock <[email protected]>

check_release.py

@@ -88,14 +88,27 @@ def main():
   header are higher than in the master branch, i.e. were bumped. """
 
   # Check that the current branch is based off of the master branch
+  current_branch = os.environ["GITHUB_REF"].lstrip("refs/")
   try:
     subprocess.run(
       shlex.split("git merge-base --is-ancestor origin/master {}".format(
-        os.environ["GITHUB_REF"].lstrip("refs/"))), check=True)
+        current_branch)), check=True)
 
   except subprocess.CalledProcessError as e:
     raise SpecError("make sure the current branch is based off of master")
 
+  # Only proceed if the spec itself was changed
+  git_run = subprocess.run(shlex.split(
+    "git diff --name-only origin/master {}".format(current_branch)),
+                           capture_output=True, check=True, text=True)
+  modified_files = git_run.stdout.split() or []
+
+  if SPEC_NAME not in modified_files:
+    print("*"*68)
+    print("{} not modified, skipping version and date check.".format(SPEC_NAME))
+    print("*"*68)
+    return
+
   # Read the first few lines from the updated specification document and
   # extract date and version from spec file header in the current branch
   spec_head = get_spec_head()