From 2f4d29158999a057c8658771b13a85f39957aa3a Mon Sep 17 00:00:00 2001
From: Anton Kosyakov <anton.kosyakov@typefox.io>
Date: Fri, 19 Jul 2019 09:53:27 +0000
Subject: [PATCH] [plugin] fix #5753: redetect languages on new grammar

Signed-off-by: Anton Kosyakov <anton.kosyakov@typefox.io>
---
 CHANGELOG.md                                      |  1 +
 packages/monaco/src/browser/monaco-editor.ts      | 15 ++++++++++++++-
 .../main/browser/plugin-contribution-handler.ts   | 10 ++++++++++
 3 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index fe1ad73c7fb7d..3e2735fe794e4 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,7 @@
 - [plugin] added support of debug activation events [#5645](https://github.com/theia-ide/theia/pull/5645)
 - [security] Bump lodash.mergewith from 4.6.1 to 4.6.2
 - [plugin] Fixed `Converting circular structure to JSON` Error [#5661](https://github.com/theia-ide/theia/pull/5661)
+- [plugin] fixed auto detection of new languages [#5753](https://github.com/theia-ide/theia/issues/5753)
 
 Breaking changes:
 
diff --git a/packages/monaco/src/browser/monaco-editor.ts b/packages/monaco/src/browser/monaco-editor.ts
index 68f6f7ad4d000..eeb8dfdec69c7 100644
--- a/packages/monaco/src/browser/monaco-editor.ts
+++ b/packages/monaco/src/browser/monaco-editor.ts
@@ -109,7 +109,7 @@ export class MonacoEditor implements TextEditor {
 
     protected addHandlers(codeEditor: IStandaloneCodeEditor): void {
         this.toDispose.push(codeEditor.onDidChangeModelLanguage(e =>
-            this.onLanguageChangedEmitter.fire(e.newLanguage)
+            this.fireLanguageChanged(e.newLanguage)
         ));
         this.toDispose.push(codeEditor.onDidChangeConfiguration(() => this.refresh()));
         this.toDispose.push(codeEditor.onDidChangeModel(() => this.refresh()));
@@ -447,12 +447,20 @@ export class MonacoEditor implements TextEditor {
         this.editor.restoreViewState(state as monaco.editor.ICodeEditorViewState);
     }
 
+    /* `true` because it is derived from an URI during the instantiation */
+    protected _languageAutoDetected = true;
+
+    get languageAutoDeteceted(): boolean {
+        return this._languageAutoDetected;
+    }
+
     async detectLanguage(): Promise<void> {
         const filename = this.uri.path.toString();
         const modeService = monaco.services.StaticServices.modeService.get();
         const firstLine = this.document.textEditorModel.getLineContent(1);
         const mode = await modeService.getOrCreateModeByFilenameOrFirstLine(filename, firstLine);
         this.setLanguage(mode.getId());
+        this._languageAutoDetected = true;
     }
 
     setLanguage(languageId: string): void {
@@ -461,6 +469,11 @@ export class MonacoEditor implements TextEditor {
         }
     }
 
+    protected fireLanguageChanged(langaugeId: string): void {
+        this._languageAutoDetected = false;
+        this.onLanguageChangedEmitter.fire(langaugeId);
+    }
+
     getResourceUri(): URI {
         return this.uri;
     }
diff --git a/packages/plugin-ext/src/main/browser/plugin-contribution-handler.ts b/packages/plugin-ext/src/main/browser/plugin-contribution-handler.ts
index 7019d13fa62bf..a363e65c6bb1c 100644
--- a/packages/plugin-ext/src/main/browser/plugin-contribution-handler.ts
+++ b/packages/plugin-ext/src/main/browser/plugin-contribution-handler.ts
@@ -29,12 +29,17 @@ import { CommandRegistry, Command, CommandHandler } from '@theia/core/lib/common
 import { Disposable, DisposableCollection } from '@theia/core/lib/common/disposable';
 import { Emitter } from '@theia/core/lib/common/event';
 import { TaskDefinitionRegistry, ProblemMatcherRegistry, ProblemPatternRegistry } from '@theia/task/lib/browser';
+import { MonacoEditor } from '@theia/monaco/lib/browser/monaco-editor';
+import { EditorManager } from '@theia/editor/lib/browser';
 
 @injectable()
 export class PluginContributionHandler {
 
     private injections = new Map<string, string[]>();
 
+    @inject(EditorManager)
+    private readonly editorManager: EditorManager;
+
     @inject(TextmateRegistry)
     private readonly grammarsRegistry: TextmateRegistry;
 
@@ -140,6 +145,11 @@ export class PluginContributionHandler {
                     });
                     monaco.languages.onLanguage(grammar.language, () => this.monacoTextmateService.activateLanguage(grammar.language!));
                 }
+                for (const editor of MonacoEditor.getAll(this.editorManager)) {
+                    if (editor.languageAutoDeteceted) {
+                        editor.detectLanguage();
+                    }
+                }
             }
         }