1 files changed, 34 insertions, 0 deletions
diff --git a/scripts/digest_compare.py b/scripts/digest_compare.py
new file mode 100755
index 0000000..b4144fe
--- /dev/null
+++ b/scripts/digest_compare.py
@@ -0,0 +1,34 @@
+#!/usr/bin/env python3
+"""Compare the `digest <frame> <time> <hex>` lines of two run logs (deterministic runs).
+
+Usage: digest_compare.py A.log B.log   → exit 0 when equal, 1 with the first difference.
+"""
+import sys
+from pathlib import Path
+
+
+def digests(path: str) -> list[str]:
+    return [line.strip() for line in Path(path).read_text(errors="replace").splitlines() if line.startswith("digest ")]
+
+
+def main(argv: list[str]) -> int:
+    if len(argv) != 3:
+        print(__doc__.strip())
+        return 2
+    a, b = digests(argv[1]), digests(argv[2])
+    if not a and not b:
+        print("FAIL: no digest lines")
+        return 1
+    for k, (x, y) in enumerate(zip(a, b), 1):
+        if x != y:
+            print(f"FAIL: digest {k} differs\n  {x}\n  {y}")
+            return 1
+    if len(a) != len(b):
+        print(f"FAIL: {len(a)} vs {len(b)} digests")
+        return 1
+    print(f"ok: {len(a)} digests equal, last {a[-1]}")
+    return 0
+
+
+if __name__ == "__main__":
+    sys.exit(main(sys.argv))