Ensure duplicate-length paste placeholders stay distinct (#7431)

Fix issue #7430 
Generate unique numbered placeholders for multiple large pastes of the
same length so deleting one no longer removes the others.

Signed-off-by: Joshua <joshua1s@protonmail.com>

codex-rs/tui/src/bottom_pane/chat_composer.rs

@@ -101,6 +101,7 @@ pub(crate) struct ChatComposer {
     dismissed_file_popup_token: Option<String>,
     current_file_query: Option<String>,
     pending_pastes: Vec<(String, String)>,
+    large_paste_counters: HashMap<usize, usize>,
     has_focus: bool,
     attached_images: Vec<AttachedImage>,
     placeholder_text: String,
@@ -147,6 +148,7 @@ impl ChatComposer {
             dismissed_file_popup_token: None,
             current_file_query: None,
             pending_pastes: Vec::new(),
+            large_paste_counters: HashMap::new(),
             has_focus: has_input_focus,
             attached_images: Vec::new(),
             placeholder_text,
@@ -222,7 +224,7 @@ impl ChatComposer {
     pub fn handle_paste(&mut self, pasted: String) -> bool {
         let char_count = pasted.chars().count();
         if char_count > LARGE_PASTE_CHAR_THRESHOLD {
-            let placeholder = format!("[Pasted Content {char_count} chars]");
+            let placeholder = self.next_large_paste_placeholder(char_count);
             self.textarea.insert_element(&placeholder);
             self.pending_pastes.push((placeholder, pasted));
         } else if char_count > 1 && self.handle_paste_image_path(pasted.clone()) {
@@ -362,6 +364,17 @@ impl ChatComposer {
         self.set_has_focus(has_focus);
     }
 
+    fn next_large_paste_placeholder(&mut self, char_count: usize) -> String {
+        let base = format!("[Pasted Content {char_count} chars]");
+        let next_suffix = self.large_paste_counters.entry(char_count).or_insert(0);
+        *next_suffix += 1;
+        if *next_suffix == 1 {
+            base
+        } else {
+            format!("{base} #{next_suffix}")
+        }
+    }
+
     pub(crate) fn insert_str(&mut self, text: &str) {
         self.textarea.insert_str(text);
         self.sync_command_popup();
@@ -2671,6 +2684,83 @@ mod tests {
         );
     }
 
+    #[test]
+    fn deleting_duplicate_length_pastes_removes_only_target() {
+        use crossterm::event::KeyCode;
+        use crossterm::event::KeyEvent;
+        use crossterm::event::KeyModifiers;
+
+        let (tx, _rx) = unbounded_channel::<AppEvent>();
+        let sender = AppEventSender::new(tx);
+        let mut composer = ChatComposer::new(
+            true,
+            sender,
+            false,
+            "Ask Codex to do anything".to_string(),
+            false,
+        );
+
+        let paste = "x".repeat(LARGE_PASTE_CHAR_THRESHOLD + 4);
+        let placeholder_base = format!("[Pasted Content {} chars]", paste.chars().count());
+        let placeholder_second = format!("{placeholder_base} #2");
+
+        composer.handle_paste(paste.clone());
+        composer.handle_paste(paste.clone());
+        assert_eq!(
+            composer.textarea.text(),
+            format!("{placeholder_base}{placeholder_second}")
+        );
+        assert_eq!(composer.pending_pastes.len(), 2);
+
+        composer.textarea.set_cursor(composer.textarea.text().len());
+        composer.handle_key_event(KeyEvent::new(KeyCode::Backspace, KeyModifiers::NONE));
+
+        assert_eq!(composer.textarea.text(), placeholder_base);
+        assert_eq!(composer.pending_pastes.len(), 1);
+        assert_eq!(composer.pending_pastes[0].0, placeholder_base);
+        assert_eq!(composer.pending_pastes[0].1, paste);
+    }
+
+    #[test]
+    fn large_paste_numbering_does_not_reuse_after_deletion() {
+        use crossterm::event::KeyCode;
+        use crossterm::event::KeyEvent;
+        use crossterm::event::KeyModifiers;
+
+        let (tx, _rx) = unbounded_channel::<AppEvent>();
+        let sender = AppEventSender::new(tx);
+        let mut composer = ChatComposer::new(
+            true,
+            sender,
+            false,
+            "Ask Codex to do anything".to_string(),
+            false,
+        );
+
+        let paste = "x".repeat(LARGE_PASTE_CHAR_THRESHOLD + 4);
+        let base = format!("[Pasted Content {} chars]", paste.chars().count());
+        let second = format!("{base} #2");
+        let third = format!("{base} #3");
+
+        composer.handle_paste(paste.clone());
+        composer.handle_paste(paste.clone());
+        assert_eq!(composer.textarea.text(), format!("{base}{second}"));
+
+        composer.textarea.set_cursor(base.len());
+        composer.handle_key_event(KeyEvent::new(KeyCode::Backspace, KeyModifiers::NONE));
+        assert_eq!(composer.textarea.text(), second);
+        assert_eq!(composer.pending_pastes.len(), 1);
+        assert_eq!(composer.pending_pastes[0].0, second);
+
+        composer.textarea.set_cursor(composer.textarea.text().len());
+        composer.handle_paste(paste);
+
+        assert_eq!(composer.textarea.text(), format!("{second}{third}"));
+        assert_eq!(composer.pending_pastes.len(), 2);
+        assert_eq!(composer.pending_pastes[0].0, second);
+        assert_eq!(composer.pending_pastes[1].0, third);
+    }
+
     #[test]
     fn test_partial_placeholder_deletion() {
         use crossterm::event::KeyCode;