Add a script to validate & fix mismatches CRLF in the repo

.pipelines/build-stage.yml

@@ -113,6 +113,9 @@ stages:
           - script: python tools\devops\validate-copyright-headers.py test
             displayName: Validate copyright headers (test/)
 
+          - script: python tools\devops\validate-line-endings.py .
+            displayName: Validate line feeds
+
           - task: CMake@1
             displayName: "CMake ."
             inputs:

tools/devops/validate-line-endings.py

@@ -0,0 +1,53 @@
+import click
+import os.path
+from git import Repo
+
+EXTENSIONS = ['.c', '.cpp', '.h', '.hpp', '.idl', '.resw']
+
+def is_source_file(path: str) -> bool:
+    return any(path.casefold().endswith(e) for e in EXTENSIONS)
+
+def has_crlf_mismatch(content: bytes) -> bool:
+    # Strip all CRLF pairs, then any remaining lone '\n' or '\r' is a mismatch.
+    stripped = content.replace(b'\r\n', b'')
+    return b'\n' in stripped or b'\r' in stripped
+
+def to_crlf(content: bytes) -> bytes:
+    # Normalize every line ending (CRLF, lone CR, lone LF) to a single CRLF.
+    return content.replace(b'\r\n', b'\n').replace(b'\r', b'\n').replace(b'\n', b'\r\n')
+
+@click.command()
+@click.argument('path', required=True, type=click.Path(exists=True))
+@click.option('--fix', is_flag=True, help='Convert mismatching files to CRLF line endings.')
+def main(path: str, fix: bool):
+    repo = Repo(path, search_parent_directories=True)
+
+    tracked = repo.git.ls_files('-z').split('\0')
+    source_files = [os.path.join(repo.working_tree_dir, e) for e in tracked if e and is_source_file(e)]
+
+    mismatches = []
+    for e in source_files:
+        with open(e, 'rb') as fd:
+            content = fd.read()
+
+        if not has_crlf_mismatch(content):
+            continue
+
+        mismatches.append(e)
+        if fix:
+            with open(e, 'wb') as fd:
+                fd.write(to_crlf(content))
+
+    if not mismatches:
+        click.secho('All files use CRLF line endings', fg='green')
+        return
+
+    listed = '\n'.join(mismatches)
+    if fix:
+        click.secho(f'Converted {len(mismatches)} files to CRLF:\n{listed}', fg='yellow')
+    else:
+        click.secho(f'{len(mismatches)} files have non-CRLF line endings:\n{listed}', fg='red')
+        raise SystemExit(1)
+
+if __name__ == '__main__':
+    main()