From 26db1be6d09033b998b5cb88f8275c9399e1f4b1 Mon Sep 17 00:00:00 2001
From: Mizev Andrew <150728785+carpalsgrabby@users.noreply.github.com>
Date: Tue, 25 Nov 2025 10:02:02 +0100
Subject: [PATCH] Add a sanity check for --metric existence

If user picks a metric not produced by app.py, they get a meaningful warning before processing.
---
 choose_best_layout.py | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/choose_best_layout.py b/choose_best_layout.py
index 8ac4dc2..45a2ae5 100644
--- a/choose_best_layout.py
+++ b/choose_best_layout.py
@@ -127,6 +127,11 @@ def main() -> None:
         print("No successful layouts computed. (Did app.py error out for all?)", file=sys.stderr)
         sys.exit(1)
 
+    # Warn if metric does not appear in ANY layout
+if all(args.metric not in lr.data for lr in layouts):
+    print(f"WARNING: metric '{args.metric}' was not found in any layout results.", file=sys.stderr)
+
+
     # choose best by metric (minimize)
     best = min(
         layouts,