Fix auto-indent to respect language-specific tabSize configuration

Co-authored-by: dibarbet <5749229+dibarbet@users.noreply.github.com>

Author: Copilot

src/lsptoolshost/autoInsert/onAutoInsert.ts

@@ -104,7 +104,7 @@ async function applyAutoInsertEdit(
     languageServer: RoslynLanguageServer,
     token: vscode.CancellationToken
 ) {
-    const formattingOptions = getFormattingOptions();
+    const formattingOptions = getFormattingOptions(uri);
     const request: RoslynProtocol.OnAutoInsertParams = {
         _vs_textDocument: textDocumentIdentifier,
         _vs_position: position,
@@ -142,8 +142,8 @@ async function applyAutoInsertEdit(
     }
 }
 
-function getFormattingOptions(): FormattingOptions {
-    const editorConfig = vscode.workspace.getConfiguration('editor');
+function getFormattingOptions(resource: vscode.Uri): FormattingOptions {
+    const editorConfig = vscode.workspace.getConfiguration('editor', resource);
     const tabSize = editorConfig.get<number>('tabSize') ?? 4;
     const insertSpaces = editorConfig.get<boolean>('insertSpaces') ?? true;
     return FormattingOptions.create(tabSize, insertSpaces);

test/lsptoolshost/integrationTests/onAutoInsert.integration.test.ts

@@ -110,6 +110,71 @@ describe(`OnAutoInsert Tests`, () => {
             }
         );
     });
+
+    test('Enter inside braces respects language-specific tabSize', async () => {
+        // Set global tabSize to 2 and C# tabSize to 4
+        const globalConfig = vscode.workspace.getConfiguration('editor');
+        const csharpConfig = vscode.workspace.getConfiguration('editor', {
+            languageId: 'csharp',
+            uri: vscode.window.activeTextEditor!.document.uri,
+        });
+
+        const originalGlobalTabSize = globalConfig.get('tabSize');
+        const originalCsharpTabSize = csharpConfig.get('tabSize');
+
+        try {
+            // Configure global tabSize to 2
+            await globalConfig.update('tabSize', 2, vscode.ConfigurationTarget.Global);
+            // Configure C# tabSize to 4
+            await vscode.workspace
+                .getConfiguration('[csharp]', vscode.window.activeTextEditor!.document.uri)
+                .update('editor.tabSize', 4, vscode.ConfigurationTarget.Global);
+
+            // Wait for configuration to propagate
+            await sleep(100);
+
+            await vscode.window.activeTextEditor!.edit((editBuilder) => {
+                editBuilder.insert(new vscode.Position(11, 15), '\n');
+            });
+
+            // OnAutoInsert is triggered by the change event but completes asynchronously, so wait for the buffer to be updated.
+
+            const expectedLines = [
+                'class DocComments',
+                '{',
+                '    //',
+                '    string M(int param1, string param2)',
+                '    {',
+                '        return null;',
+                '    }',
+                '',
+                '    /// <summary>',
+                '',
+                '    /// </summary>',
+                '    void M2()',
+                '    {',
+                '        ', // Should be 4 spaces (C# setting), not 2 (global setting)
+                '    }',
+                '}',
+                '',
+            ];
+
+            await waitForExpectedResult<string | undefined>(
+                async () => vscode.window.activeTextEditor?.document.getText(),
+                10000,
+                100,
+                (input) => {
+                    expect(input).toBe(expectedLines.join(EOL));
+                }
+            );
+        } finally {
+            // Restore original settings
+            await globalConfig.update('tabSize', originalGlobalTabSize, vscode.ConfigurationTarget.Global);
+            await vscode.workspace
+                .getConfiguration('[csharp]', vscode.window.activeTextEditor!.document.uri)
+                .update('editor.tabSize', originalCsharpTabSize, vscode.ConfigurationTarget.Global);
+        }
+    });
 });
 
 function normalizeNewlines(text: string | undefined): string | undefined {