From 25deb499bf903c389be462c80302b0c8bea6ffa0 Mon Sep 17 00:00:00 2001
From: jochen <jschoubben@gmail.com>
Date: Mon, 12 Oct 2026 17:31:36 +0200
Subject: [PATCH] Say why a merge's changed files read as none on an error

---
 internal/builder/check_merge.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/internal/builder/check_merge.go b/internal/builder/check_merge.go
index fda7f359..b9423ab8 100644
--- a/internal/builder/check_merge.go
+++ b/internal/builder/check_merge.go
@@ -85,7 +85,7 @@ func changedByMerge(ctx context.Context, run Runner, tree string, m TrunkMerge)
 	}
 	out, err := run(ctx, tree, "git", "diff", "--name-only", "--no-renames", m.Trunk, m.Merge)
 	if err != nil {
-		return nil
+		return nil // empty-on-error: the caller keeps the pull request's own list of changed files, the safe one
 	}
 	return strings.Fields(out)
 }