fix(plugin-ext): match custom editor filenamePattern against full path

packages/plugin-ext/src/main/browser/custom-editors/custom-editor-opener.spec.ts

@@ -0,0 +1,104 @@
+// *****************************************************************************
+// Copyright (C) 2026 Safi Seid-Ahmad, K2view and others.
+//
+// This program and the accompanying materials are made available under the
+// terms of the Eclipse Public License v. 2.0 which is available at
+// http://www.eclipse.org/legal/epl-2.0.
+//
+// This Source Code may also be made available under the following Secondary
+// Licenses when the conditions for such availability set forth in the Eclipse
+// Public License v. 2.0 are satisfied: GNU General Public License, version 2
+// with the GNU Classpath Exception which is available at
+// https://www.gnu.org/software/classpath/license.html.
+//
+// SPDX-License-Identifier: EPL-2.0 OR GPL-2.0-only WITH Classpath-exception-2.0
+// *****************************************************************************
+
+import { enableJSDOM } from '@theia/core/lib/browser/test/jsdom';
+let disableJSDOM = enableJSDOM();
+
+import * as chai from 'chai';
+import URI from '@theia/core/lib/common/uri';
+import { CustomEditorOpener } from './custom-editor-opener';
+import { CustomEditor, CustomEditorPriority } from '../../../common';
+
+disableJSDOM();
+
+const expect = chai.expect;
+
+describe('CustomEditorOpener#selectorMatches', () => {
+
+    before(() => {
+        disableJSDOM = enableJSDOM();
+    });
+
+    after(() => {
+        disableJSDOM();
+    });
+
+    // Only selector matching is exercised — none of the collaborators are touched.
+    function createOpener(filenamePattern: string): CustomEditorOpener {
+        const editor: CustomEditor = {
+            viewType: 'test.editor',
+            displayName: 'Test Editor',
+            selector: [{ filenamePattern }],
+            priority: CustomEditorPriority.default
+        };
+        return new CustomEditorOpener(editor, undefined!, undefined!, undefined!, undefined!);
+    }
+
+    function matches(filenamePattern: string, path: string): boolean {
+        const opener = createOpener(filenamePattern);
+        return opener.matches([{ filenamePattern }], new URI(`file://${path}`));
+    }
+
+    function matchesUri(filenamePattern: string, uri: string): boolean {
+        const opener = createOpener(filenamePattern);
+        return opener.matches([{ filenamePattern }], new URI(uri));
+    }
+
+    it('matches a plain extension pattern against the basename', () => {
+        expect(matches('*.custom', '/project/src/file.custom')).true;
+        expect(matches('*.custom', '/project/src/file.other')).false;
+    });
+
+    it('matches a plain filename pattern against the basename anywhere', () => {
+        expect(matches('config.json', '/anywhere/at/all/config.json')).true;
+        expect(matches('config.json', '/anywhere/at/all/other.json')).false;
+    });
+
+    it('matches case-insensitively', () => {
+        expect(matches('*.CUSTOM', '/project/file.custom')).true;
+        expect(matches('*.custom', '/project/FILE.CUSTOM')).true;
+    });
+
+    it('matches a pattern containing a path separator against the full path (VS Code parity)', () => {
+        const pattern = '**/components/*/config.json';
+        expect(matches(pattern, '/project/src/components/button/config.json')).true;
+        expect(matches(pattern, '/project/elsewhere/config.json')).false;
+        expect(matches(pattern, '/project/src/components/button/nested/config.json')).false;
+    });
+
+    it('matches nested path patterns', () => {
+        const pattern = '**/components/*/styles/*.css';
+        expect(matches(pattern, '/project/src/components/button/styles/theme.css')).true;
+        expect(matches(pattern, '/project/src/components/button/config.json')).false;
+        expect(matches(pattern, '/project/src/components/button/styles/dark/theme.css')).false;
+    });
+
+    it('does not let a path pattern match a bare basename', () => {
+        expect(matches('**/components/*/config.json', '/config.json')).false;
+    });
+
+    it('never matches the excluded schemes, mirroring VS Code (globMatchesResource)', () => {
+        // Patterns that would match the basename or full path on a `file:` resource...
+        expect(matchesUri('*.json', 'file:///project/settings.json')).true;
+        expect(matchesUri('**/settings.json', 'file:///project/settings.json')).true;
+        // ...must not match on VS Code's internal schemes.
+        expect(matchesUri('*.json', 'vscode-settings:/settings.json')).false;
+        expect(matchesUri('**/settings.json', 'vscode-settings:/project/settings.json')).false;
+        expect(matchesUri('*.json', 'webview-panel:/panel/config.json')).false;
+        expect(matchesUri('*', 'extension:/some/resource')).false;
+        expect(matchesUri('*', 'vscode-workspace-trust:/trust')).false;
+    });
+});

packages/plugin-ext/src/main/browser/custom-editors/custom-editor-opener.tsx

@@ -24,6 +24,20 @@ import { PluginCustomEditorRegistry } from './plugin-custom-editor-registry';
 import { generateUuid } from '@theia/core/lib/common/uuid';
 import { DisposableCollection, Emitter, PreferenceService } from '@theia/core';
 import { match } from '@theia/core/lib/common/glob';
+import { Schemes } from '../../../common/uri-components';
+
+/**
+ * Schemes that never match a custom editor's `filenamePattern`, mirroring the
+ * excluded schemes in VS Code's `editorResolverService#globMatchesResource`.
+ * Theia has no scheme constants for `extension` and `vscode-workspace-trust`,
+ * so those are referenced by their literal values.
+ */
+const nonMatchingSchemes = new Set<string>([
+    'extension',
+    Schemes.webviewPanel,
+    'vscode-workspace-trust',
+    Schemes.vscodeSettings
+]);
 
 export class CustomEditorOpener implements OpenHandler {
 
@@ -200,8 +214,19 @@ export class CustomEditorOpener implements OpenHandler {
     }
 
     selectorMatches(selector: CustomEditorSelector, resource: URI): boolean {
+        if (nonMatchingSchemes.has(resource.scheme)) {
+            // These schemes match no glob pattern, mirroring VS Code's `globMatchesResource`.
+            return false;
+        }
         if (selector.filenamePattern) {
-            if (match(selector.filenamePattern.toLowerCase(), resource.path.name.toLowerCase() + resource.path.ext.toLowerCase())) {
+            const filenamePattern = selector.filenamePattern.toLowerCase();
+            // Mirror VS Code's editor-association matching (editorResolverService#globMatchesResource):
+            // a pattern containing a path separator is matched against the full `scheme:path`,
+            // a plain pattern is matched against the basename only.
+            const target = filenamePattern.includes('/')
+                ? `${resource.scheme}:${resource.path.toString()}`.toLowerCase()
+                : resource.path.base.toLowerCase();
+            if (match(filenamePattern, target)) {
                 return true;
             }
         }