.pre-commit-config.yaml

@@ -5,26 +5,35 @@ ci:
 
 repos:
   - repo: https://github.com/codespell-project/codespell
-    rev: 193cd7d27cd571f79358af09a8fb8997e54f8fff  # frozen: v2.3.0
+    rev: 193cd7d27cd571f79358af09a8fb8997e54f8fff # frozen: v2.3.0
     hooks:
-    - id: codespell
-      # Additional dependency needed until Python 3.11 is our minimum version.
-      additional_dependencies:
-        - tomli
+      - id: codespell
+        # Additional dependency needed until Python 3.11 is our minimum version.
+        additional_dependencies:
+          - tomli
 
   - repo: https://github.com/astral-sh/ruff-pre-commit
-    # Ruff version.
-    rev: 73413df07b4ab0bf103ca1ae73c7cec5c0ace593  # frozen: v0.9.2
+    rev: 73413df07b4ab0bf103ca1ae73c7cec5c0ace593 # frozen: v0.9.2
     hooks:
       - id: ruff
-        args: [ --fix, --show-fixes, --exit-non-zero-on-fix ]
+        args: [--fix, --show-fixes, --exit-non-zero-on-fix]
       - id: ruff-format
 
+  - repo: local
+    hooks:
+      - id: sort-json
+        name: Sort JSON
+        description: Recursively sort JSON files by key.
+        entry: ./scripts/sort_json.py
+        language: script
+        types: [json]
+        files: src/CSET/operators/_colorbar_definition.json
+
   - repo: https://github.com/pre-commit/pre-commit-hooks
-    rev: cef0300fd0fc4d2a87a85fa2093c6b283ea36f4b  # frozen: v5.0.0
+    rev: cef0300fd0fc4d2a87a85fa2093c6b283ea36f4b # frozen: v5.0.0
     hooks:
       - id: check-added-large-files
-        args: ['--maxkb=10240']
+        args: ["--maxkb=10240"]
       - id: check-case-conflict
       - id: check-merge-conflict
       - id: check-toml

scripts/sort_json.py

@@ -16,6 +16,7 @@
 """Sort a JSON file."""
 
 import argparse
+import hashlib
 import json
 import os
 import sys
@@ -52,9 +53,21 @@ def main():
         # End file with a newline.
         fp.write("\n")
 
-    # Atomically replace original file.
-    os.rename(output_file, args.input_file)
-    return 0
+    # Check if sorting changed the file.
+    with open(args.input_file, "rb") as fp:
+        original_digest = hashlib.file_digest(fp, "sha256").digest()
+    with open(output_file, "rb") as fp:
+        new_digest = hashlib.file_digest(fp, "sha256").digest()
+
+    if original_digest == new_digest:
+        # File unchanged, don't overwrite and return zero.
+        os.remove(output_file)
+        return 0
+    else:
+        # File changed, overwrite and return non-zero.
+        # Atomically replace original file via rename.
+        os.rename(output_file, args.input_file)
+        return 1
 
 
 if __name__ == "__main__":