From 3047d4be1fae4280ee466a31b45aef72c850abde Mon Sep 17 00:00:00 2001
From: Priyanshu Jain <jain.yashu2211@gmail.com>
Date: Wed, 8 Jul 2026 14:39:21 +0530
Subject: [PATCH 1/3] fix(editor): prevent syntax highlight color flicker on
 state recreation (#2304)

---
 src/lib/editorFile.js    |  2 ++
 src/lib/editorManager.js | 20 ++++++++++++++++++--
 2 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/src/lib/editorFile.js b/src/lib/editorFile.js
index c59127d03..b151fda80 100644
--- a/src/lib/editorFile.js
+++ b/src/lib/editorFile.js
@@ -1465,6 +1465,8 @@ export default class EditorFile {
 		// Store mode info for later use when creating editor view
 		this.currentMode = mode;
 		this.currentLanguageExtension = modeInfo?.getExtension() || null;
+		this.__cmCachedLanguageExtension = null;
+		this.__cmCachedLanguageSignature = null;
 		if (options.recommend !== false) {
 			maybeRecommendLanguageModeExtension(this, modeInfo);
 		}
diff --git a/src/lib/editorManager.js b/src/lib/editorManager.js
index 3a12f6184..85a6a1399 100644
--- a/src/lib/editorManager.js
+++ b/src/lib/editorManager.js
@@ -2705,6 +2705,8 @@ async function EditorManager($header, $body) {
 		targetEditor = editor,
 	) {
 		try {
+			file.__cmCachedLanguageExtension = ext || [];
+			file.__cmCachedLanguageSignature = languageSignature;
 			targetEditor.dispatch({
 				effects: languageCompartment.reconfigure(ext || []),
 			});
@@ -2722,6 +2724,14 @@ async function EditorManager($header, $body) {
 			return [];
 		}
 
+		if (
+			file.__cmCachedLanguageExtension &&
+			file.__cmCachedLanguageSignature === languageSignature
+		) {
+			markLanguageReady(file, languageSignature, true);
+			return file.__cmCachedLanguageExtension;
+		}
+
 		let result;
 		try {
 			result = langExtFn();
@@ -2735,11 +2745,15 @@ async function EditorManager($header, $body) {
 			markLanguageReady(file, languageSignature, false);
 			result
 				.then((ext) => {
+					if (file.__cmLanguageSignature !== languageSignature) {
+						return;
+					}
+					file.__cmCachedLanguageExtension = ext || [];
+					file.__cmCachedLanguageSignature = languageSignature;
 					const pane = getFileLspPane(file);
 					if (
 						!pane?.editor ||
-						pane.activeFile?.id !== fileId ||
-						file.__cmLanguageSignature !== languageSignature
+						pane.activeFile?.id !== fileId
 					) {
 						return;
 					}
@@ -2759,6 +2773,8 @@ async function EditorManager($header, $body) {
 		}
 
 		markLanguageReady(file, languageSignature, true);
+		file.__cmCachedLanguageExtension = result || [];
+		file.__cmCachedLanguageSignature = languageSignature;
 		return result || [];
 	}
 

From fa4e0082acc92e283358d4d563b4e9e727b5c3cf Mon Sep 17 00:00:00 2001
From: Priyanshu Jain <jain.yashu2211@gmail.com>
Date: Wed, 8 Jul 2026 14:42:40 +0530
Subject: [PATCH 2/3] style: normalize line endings with biome format

---
 src/lib/editorManager.js | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/src/lib/editorManager.js b/src/lib/editorManager.js
index 85a6a1399..4fde43cc2 100644
--- a/src/lib/editorManager.js
+++ b/src/lib/editorManager.js
@@ -2751,10 +2751,7 @@ async function EditorManager($header, $body) {
 					file.__cmCachedLanguageExtension = ext || [];
 					file.__cmCachedLanguageSignature = languageSignature;
 					const pane = getFileLspPane(file);
-					if (
-						!pane?.editor ||
-						pane.activeFile?.id !== fileId
-					) {
+					if (!pane?.editor || pane.activeFile?.id !== fileId) {
 						return;
 					}
 

From a9dbf875479f54a091df2d7b08f41f7080e08c00 Mon Sep 17 00:00:00 2001
From: Priyanshu Jain <jain.yashu2211@gmail.com>
Date: Wed, 8 Jul 2026 14:58:34 +0530
Subject: [PATCH 3/3] fix(editor): move language extension cache assignment
 after successful dispatch

---
 src/lib/editorManager.js | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/lib/editorManager.js b/src/lib/editorManager.js
index 4fde43cc2..84b905999 100644
--- a/src/lib/editorManager.js
+++ b/src/lib/editorManager.js
@@ -2705,12 +2705,12 @@ async function EditorManager($header, $body) {
 		targetEditor = editor,
 	) {
 		try {
-			file.__cmCachedLanguageExtension = ext || [];
-			file.__cmCachedLanguageSignature = languageSignature;
 			targetEditor.dispatch({
 				effects: languageCompartment.reconfigure(ext || []),
 			});
 			file.session = targetEditor.state;
+			file.__cmCachedLanguageExtension = ext || [];
+			file.__cmCachedLanguageSignature = languageSignature;
 			markLanguageReady(file, languageSignature, true);
 		} catch (error) {
 			warnRecoverable("Failed to apply language extensions.", error, warnKey);