From 957453e8ed4f42adfbe68e5b51c5bcc5eaea5360 Mon Sep 17 00:00:00 2001
From: Ken Micklas <git@kmicklas.com>
Date: Sun, 8 Oct 2023 10:38:09 +0100
Subject: [PATCH] Handle suffixes of cancelled keymaps in insert mode

---
 helix-term/src/ui/editor.rs | 48 +++++++++++++++++++++++--------------
 1 file changed, 30 insertions(+), 18 deletions(-)

diff --git a/helix-term/src/ui/editor.rs b/helix-term/src/ui/editor.rs
index dd6fff087bee3..0328e1d81b29b 100644
--- a/helix-term/src/ui/editor.rs
+++ b/helix-term/src/ui/editor.rs
@@ -29,7 +29,7 @@ use helix_view::{
     keyboard::{KeyCode, KeyModifiers},
     Document, Editor, Theme, View,
 };
-use std::{mem::take, num::NonZeroUsize, path::PathBuf, rc::Rc, sync::Arc};
+use std::{collections::VecDeque, mem::take, num::NonZeroUsize, path::PathBuf, rc::Rc, sync::Arc};
 
 use tui::{buffer::Buffer as Surface, text::Span};
 
@@ -857,28 +857,40 @@ impl EditorView {
     }
 
     fn insert_mode(&mut self, cx: &mut commands::Context, event: KeyEvent) {
-        if let Some(keyresult) = self.handle_keymap_event(Mode::Insert, cx, event) {
-            match keyresult {
-                KeymapResult::NotFound => {
-                    if let Some(ch) = event.char() {
-                        commands::insert::insert_char(cx, ch)
+        let mut queue = VecDeque::from([event]);
+
+        while let Some(event) = queue.pop_front() {
+            if let Some(keyresult) = self.handle_keymap_event(Mode::Insert, cx, event) {
+                match keyresult {
+                    KeymapResult::NotFound => {
+                        if let Some(ch) = event.char() {
+                            commands::insert::insert_char(cx, ch)
+                        }
                     }
-                }
-                KeymapResult::Cancelled(pending) => {
-                    for ev in pending {
-                        match ev.char() {
-                            Some(ch) => commands::insert::insert_char(cx, ch),
-                            None => {
-                                if let KeymapResult::Matched(command) =
-                                    self.keymaps.get(Mode::Insert, ev)
-                                {
-                                    command.execute(cx);
-                                }
+                    KeymapResult::Cancelled(pending) => {
+                        let mut pending = pending.into_iter();
+                        if let Some(first) = pending.next() {
+                            // Note that since this is the first pending key, we know
+                            // it can't map to a command by itself.
+                            match first.char() {
+                                // The first key is both the start of a menu and a regular
+                                // insert key. The user may have intended to type it as an
+                                // insert, and then execute the remaining suffix of keys.
+                                Some(ch) => commands::insert::insert_char(cx, ch),
+                                // If the first key is not a character to insert, then we
+                                // assume the user intended to enter a command menu, so we
+                                // should just discard pending keys if they don't match.
+                                None => continue,
                             }
                         }
+
+                        // Sadly VecDeque has no extend_front method.
+                        for event in pending.rev() {
+                            queue.push_front(event);
+                        }
                     }
+                    _ => unreachable!(),
                 }
-                _ => unreachable!(),
             }
         }
     }