fix(tui): attach every line range when one file is mentioned twice (#7259)

* fix(tui): attach every line range when one file is mentioned twice

Mentions are deduplicated before they are attached, and a resolved file
is keyed by its path alone. `compare @notes.txt:1-1 with @notes.txt:4-4`
therefore attached lines 1-1 and dropped 4-4, while the composer showed a
"resolved on send" chip for each and the model got no hint that the
second range was missing.

Key a ranged mention by path and range. Repeating the same range, or the
whole file, still deduplicates as before.

Signed-off-by: Lstarsky0 <[email protected]>

* fix(tui): keep a range key from matching a literal file name

The range was joined to the path with `:`, which a file name can contain.
With files `notes.txt` and `notes.txt:1-1`, `@notes.txt:01-01
@notes.txt:1-1` gave both the key `notes.txt:1-1`, and the literal file
was dropped. Join them with a NUL, which no path contains.

Signed-off-by: Lstarsky0 <[email protected]>

---------

Signed-off-by: Lstarsky0 <[email protected]>

crates/tui/src/tui/file_mention.rs

@@ -1119,7 +1119,10 @@ fn local_context_from_file_mentions(
         // Missing mentions dedup on the typed token: there is no resolved
         // path to key on, and the workspace-root guess must not become one.
         let dedup_key = if exists {
-            display_path.clone()
+            match range {
+                Some(FileRange { start, end }) => format!("{display_path}\0{start}-{end}"),
+                None => display_path.clone(),
+            }
         } else {
             format!("missing:{mention}")
         };
@@ -1737,6 +1740,32 @@ mod tests {
         assert!(!content.contains("<missing-file"), "got: {content}");
     }
 
+    #[test]
+    fn two_ranges_of_one_file_are_both_attached() {
+        let tmp = TempDir::new().expect("tempdir");
+        std::fs::write(tmp.path().join("notes.txt"), "one\ntwo\nthree\nfour\n").expect("write");
+
+        let content = user_request_with_file_mentions(
+            "compare @notes.txt:1-1 with @notes.txt:4-4",
+            tmp.path(),
+            None,
+        );
+
+        assert!(content.contains("lines=\"1-1\">\none\n"), "got: {content}");
+        assert!(content.contains("lines=\"4-4\">\nfour\n"), "got: {content}");
+
+        if cfg!(unix) {
+            std::fs::write(tmp.path().join("notes.txt:1-1"), "literal\n").expect("write");
+            let content = user_request_with_file_mentions(
+                "@notes.txt:01-01 @notes.txt:1-1",
+                tmp.path(),
+                None,
+            );
+            assert!(content.contains("lines=\"1-1\">\none\n"), "got: {content}");
+            assert!(content.contains("literal\n"), "got: {content}");
+        }
+    }
+
     /// Negative test: a truly missing path still produces `<missing-file>`
     /// so the user gets an explicit signal instead of silent failure.
     #[test]