From 1eb74acb3ecc474163b52b564f8071df0525a579 Mon Sep 17 00:00:00 2001
From: Piotr Osiewicz <24362066+osiewicz@users.noreply.github.com>
Date: Thu, 14 Sep 2023 20:24:21 +0200
Subject: [PATCH] editor: Do not run brace completion on empty text. (#2965)

Users of keyboard layout with IME complained about the peculiar
behaviour where typing in "sss" and then removing all of it left behind
one 's' and also appended a closing brace. This was not reproducible on
a buffer without language, so I've suspected that brace insertion might
be a problem here. For whatever reason when the user removes the last
character from a run that triggered IME, we receive a notification about
an empty insertion. Sadly, brace completion does not handle an empty
input properly and we erroneously insert a closing brace when deleting
the followup characters. In fact, the brace inserted is always the
closing brace for the first entry in language's config.toml 'brackets'
field (see Scheme vs Markdown). This guard also allows for the proper
removal of the first character.

Closes community tickets zed-industries/community#877
zed-industries/community#1329

Z-2869

Release Notes:
- Fixed handling of bracket completion for international keyboard
layouts that use IME. This led to Zed erroneously inserting the `}`
character while removing the first character that triggered IME.
---
 crates/editor/src/editor.rs | 20 ++++++++++++--------
 1 file changed, 12 insertions(+), 8 deletions(-)

diff --git a/crates/editor/src/editor.rs b/crates/editor/src/editor.rs
index d651980f331f0e8f08e2d0d3bddc52d1c0f7fc7e..3f94f815f2f346916c3b215acead0d71469e6bcc 100644
--- a/crates/editor/src/editor.rs
+++ b/crates/editor/src/editor.rs
@@ -2289,14 +2289,18 @@ impl Editor {
                 // bracket of any of this language's bracket pairs.
                 let mut bracket_pair = None;
                 let mut is_bracket_pair_start = false;
-                for (pair, enabled) in scope.brackets() {
-                    if enabled && pair.close && pair.start.ends_with(text.as_ref()) {
-                        bracket_pair = Some(pair.clone());
-                        is_bracket_pair_start = true;
-                        break;
-                    } else if pair.end.as_str() == text.as_ref() {
-                        bracket_pair = Some(pair.clone());
-                        break;
+                if !text.is_empty() {
+                    // `text` can be empty when an user is using IME (e.g. Chinese Wubi Simplified)
+                    //  and they are removing the character that triggered IME popup.
+                    for (pair, enabled) in scope.brackets() {
+                        if enabled && pair.close && pair.start.ends_with(text.as_ref()) {
+                            bracket_pair = Some(pair.clone());
+                            is_bracket_pair_start = true;
+                            break;
+                        } else if pair.end.as_str() == text.as_ref() {
+                            bracket_pair = Some(pair.clone());
+                            break;
+                        }
                     }
                 }