Add a skill to produce a summary report for changes to testdata files. (#6925)

Example output from Gemini: https://gist.github.com/zygoloid/b4aaaf919173d639cf0ffa90fd0898e4 Assisted-by: Gemini 3.1 Pro via Antigravity --------- Co-authored-by: Dana Jansens <danakj@orodu.net>
2026-10-05 08:31:04 +01:00 · 2026-03-18 16:05:10 +00:00
parent d47b6221ae
commit 98e2567524
2 changed files with 268 additions and 0 deletions
@@ -0,0 +1,65 @@
+__copyright__ = """
+Part of the Carbon Language project, under the Apache License v2.0 with LLVM
+Exceptions. See /LICENSE for license information.
+SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+"""
+
+import sys
+from collections import defaultdict
+from typing import TextIO, Dict, List
+
+
+def parse_diff(stream: TextIO) -> None:
+    current_file: str = ""
+    file_changes: Dict[str, Dict[str, List[str]]] = defaultdict(
+        lambda: {"input": [], "stderr": [], "stdout": []}
+    )
+
+    for line in stream:
+        if line.startswith("diff --git"):
+            parts = line.split()
+            if len(parts) >= 4:
+                current_file = (
+                    parts[3][2:] if parts[3].startswith("b/") else parts[3]
+                )
+        elif line.startswith("+") or line.startswith("-"):
+            if not line.startswith("+++") and not line.startswith("---"):
+                stripped = line[1:].strip()
+                if stripped.startswith("// CHECK:STDERR"):
+                    file_changes[current_file]["stderr"].append(
+                        line.rstrip("\n")
+                    )
+                elif stripped.startswith("// CHECK:STDOUT"):
+                    file_changes[current_file]["stdout"].append(
+                        line.rstrip("\n")
+                    )
+                elif stripped.startswith("// CHECK"):
+                    file_changes[current_file]["stdout"].append(
+                        line.rstrip("\n")
+                    )
+                else:
+                    file_changes[current_file]["input"].append(
+                        line.rstrip("\n")
+                    )
+
+    for f, c in file_changes.items():
+        if not c["input"] and not c["stderr"] and not c["stdout"]:
+            continue
+        print(f"File: {f}")
+        if c["input"]:
+            print("  --- Input Changes ---")
+            for change in c["input"]:
+                print(f"  {change}")
+        if c["stderr"]:
+            print("  --- STDERR Changes ---")
+            for change in c["stderr"]:
+                print(f"  {change}")
+        if c["stdout"]:
+            print("  --- STDOUT Changes ---")
+            for change in c["stdout"]:
+                print(f"  {change}")
+        print("-" * 40)
+
+
+if __name__ == "__main__":
+    parse_diff(sys.stdin)