gui: name the other copy of a duplicate, and offer to keep this one instead

1 files changed, 8 insertions, 0 deletions

diff --git a/internal/engine/match.go b/internal/engine/match.go
index 59cea42..25c05e5 100644
--- a/internal/engine/match.go
+++ b/internal/engine/match.go
@@ -46,6 +46,13 @@ type FileMatch struct {
 	// directory's rules use, or that check failed. Only set for a file some
 	// matching rule would delete.
 	NoDelete string
+
+	// DuplicateOf is the file a (duplicate) test matched this one against,
+	// absolute; "" when none did. The reason text says the same thing the
+	// way it reads best - relative to the directory when it is inside it -
+	// which leaves a front end no way to act on the other copy, or even to
+	// say where it is (his report, 2026-09-17).
+	DuplicateOf string
 }
 
 // Result is everything Match found in one directory.
@@ -190,6 +197,7 @@ func evalFile(run *matchRun, file scan.File) FileMatch {
 	if len(run.d.DupScopes) > 0 && deletes(fm.Rules) {
 		fm.NoDelete = noDelete(f, run.d.DupScopes)
 	}
+	fm.DuplicateOf = f.DuplicateOriginal()
 	return fm
 }