Fix source.fixAll.prettier respecting editor.defaultFormatter (#3908) (#3937)

* Fix source.fixAll.prettier respecting editor.defaultFormatter (#3908)

The code action provider now checks the user's editor settings before
providing code actions. This prevents Prettier from running via
source.fixAll when the user has explicitly chosen a different formatter
(e.g., ESLint with Prettier plugin).

The code action will now only run when:
1. source.fixAll.prettier is explicitly set to "always" or "explicit"
2. editor.defaultFormatter is not set to another extension

This fix also properly handles language-specific settings (e.g.,
[javascript]: { "editor.defaultFormatter": "..." }).

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* Add delay and timeout to code action tests for CI stability

The tests were timing out on CI (Linux) because they need time for
formatter registration when switching to a new workspace folder.

- Added 1 second delay after showing document to wait for formatter registration
- Increased test timeout to 10 seconds for workspace folder tests

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

Author: ntotten

CHANGELOG.md

@@ -6,6 +6,8 @@ All notable changes to the "prettier-vscode" extension will be documented in thi
 
 ## [Unreleased]
 
+- Fixed `source.fixAll.prettier` code action running even when `editor.defaultFormatter` was set to a different extension (#3908). The code action now respects the user's formatter choice and only runs when Prettier is the default formatter or when `source.fixAll.prettier` is explicitly enabled.
+
 ## [12.1.1]
 
 - Fixed module resolution when `prettierPath` points to a file (e.g., `.yarn/sdks/prettier/index.cjs` in Yarn PnP SDK setups)

README.md

@@ -255,6 +255,8 @@ You can also combine Prettier with ESLint:
 }
 ```
 
+> **Note:** The `source.fixAll.prettier` code action respects your `editor.defaultFormatter` setting. If you have set a different default formatter (e.g., ESLint with Prettier plugin), the Prettier code action will not run unless you explicitly enable it with `"source.fixAll.prettier": "explicit"` or `"source.fixAll.prettier": "always"`. This prevents double-formatting when using setups like `eslint-plugin-prettier`.
+
 ## Workspace Trust
 
 This extension utilizes VS Code [Workspace Trust](https://code.visualstudio.com/docs/editor/workspace-trust) features. When this extension is run on an untrusted workspace, it will only use the built in version of prettier. No plugins, local, or global modules will be supported. Additionally, certain settings are also restricted - see each setting for details.

src/PrettierCodeActionProvider.ts

@@ -7,10 +7,13 @@ import {
   Range,
   TextDocument,
   TextEdit,
+  workspace,
   WorkspaceEdit,
 } from "vscode";
 import { ExtensionFormattingOptions } from "./types.js";
 
+const EXTENSION_ID = "esbenp.prettier-vscode";
+
 /**
  * Provides code actions for formatting with Prettier.
  * This enables using Prettier with codeActionsOnSave.
@@ -27,6 +30,47 @@ export class PrettierCodeActionProvider implements CodeActionProvider {
     ) => Promise<TextEdit[]>,
   ) {}
 
+  /**
+   * Check if the Prettier code action should run for this document.
+   * Returns true if:
+   * 1. source.fixAll.prettier is explicitly enabled in codeActionsOnSave, OR
+   * 2. editor.defaultFormatter is NOT set to another extension
+   *
+   * This prevents Prettier from running via source.fixAll when the user has
+   * explicitly chosen a different formatter (e.g., ESLint with Prettier plugin).
+   * See: https://github.com/prettier/prettier-vscode/issues/3908
+   */
+  private shouldProvideCodeActions(document: TextDocument): boolean {
+    // Use languageId scope to get language-specific settings (e.g., [javascript])
+    const editorConfig = workspace.getConfiguration("editor", {
+      uri: document.uri,
+      languageId: document.languageId,
+    });
+
+    // Check if source.fixAll.prettier is explicitly enabled - if so, always provide actions
+    const codeActionsOnSave = editorConfig.get<Record<string, string>>(
+      "codeActionsOnSave",
+      {},
+    );
+    const prettierFixAllSetting = codeActionsOnSave["source.fixAll.prettier"];
+    if (
+      prettierFixAllSetting === "always" ||
+      prettierFixAllSetting === "explicit"
+    ) {
+      return true;
+    }
+
+    // Check if editor.defaultFormatter is explicitly set to another extension
+    // If so, don't provide code actions (user chose a different formatter)
+    const defaultFormatter = editorConfig.get<string>("defaultFormatter");
+    if (defaultFormatter && defaultFormatter !== EXTENSION_ID) {
+      return false;
+    }
+
+    // Default: provide code actions (either no formatter set, or Prettier is the formatter)
+    return true;
+  }
+
   public async provideCodeActions(
     document: TextDocument,
     // eslint-disable-next-line @typescript-eslint/no-unused-vars
@@ -36,6 +80,11 @@ export class PrettierCodeActionProvider implements CodeActionProvider {
     // eslint-disable-next-line @typescript-eslint/no-unused-vars
     token: CancellationToken,
   ): Promise<CodeAction[]> {
+    // Only provide code actions if explicitly enabled or if Prettier is the default formatter
+    if (!this.shouldProvideCodeActions(document)) {
+      return [];
+    }
+
     const edits = await this.provideEdits(document, {
       force: false,
     });

src/test/suite/codeAction.test.ts

@@ -1,6 +1,14 @@
 import * as assert from "assert";
 import * as vscode from "vscode";
 import { ensureExtensionActivated } from "./testUtils.js";
+import { getWorkspaceFolderUri } from "./formatTestUtils.js";
+
+/**
+ * Helper to wait for a specified number of milliseconds
+ */
+function delay(ms: number): Promise<void> {
+  return new Promise((resolve) => setTimeout(resolve, ms));
+}
 
 describe("Test Prettier Code Actions", () => {
   const unformattedCode = `const  x   =  {  a: 1, b: 2  }`;
@@ -79,4 +87,73 @@ describe("Test Prettier Code Actions", () => {
       "Document should be formatted correctly after applying code action",
     );
   });
+
+  it("does NOT provide code action when defaultFormatter is not prettier", async function () {
+    // Increase timeout for this test as it involves workspace folder switching
+    this.timeout(10000);
+
+    // The 'workspace' folder has editor.defaultFormatter set to
+    // vscode.typescript-language-features for JavaScript files
+    const base = getWorkspaceFolderUri("workspace");
+    const testFilePath = vscode.Uri.joinPath(base, "test.js");
+    const doc = await vscode.workspace.openTextDocument(testFilePath);
+    await vscode.window.showTextDocument(doc);
+
+    // Wait for formatter registration to complete
+    await delay(1000);
+
+    // Get code actions for the document
+    const codeActions = await vscode.commands.executeCommand<
+      vscode.CodeAction[]
+    >(
+      "vscode.executeCodeActionProvider",
+      doc.uri,
+      new vscode.Range(0, 0, doc.lineCount, 0),
+    );
+
+    // Prettier code action should NOT be available
+    const prettierAction = codeActions?.find(
+      (action) => action.kind?.value === "source.fixAll.prettier",
+    );
+
+    assert.ok(
+      !prettierAction,
+      "Prettier code action should NOT be available when defaultFormatter is not prettier",
+    );
+  });
+
+  it("provides code action when source.fixAll.prettier is explicitly enabled", async function () {
+    // Increase timeout for this test as it involves workspace folder switching
+    this.timeout(10000);
+
+    // The 'workspace-explicit-prettier' folder has:
+    // - editor.defaultFormatter set to a different formatter
+    // - BUT source.fixAll.prettier is explicitly set to "always"
+    const base = getWorkspaceFolderUri("workspace-explicit-prettier");
+    const testFilePath = vscode.Uri.joinPath(base, "test.js");
+    const doc = await vscode.workspace.openTextDocument(testFilePath);
+    await vscode.window.showTextDocument(doc);
+
+    // Wait for formatter registration to complete
+    await delay(1000);
+
+    // Get code actions for the document
+    const codeActions = await vscode.commands.executeCommand<
+      vscode.CodeAction[]
+    >(
+      "vscode.executeCodeActionProvider",
+      doc.uri,
+      new vscode.Range(0, 0, doc.lineCount, 0),
+    );
+
+    // Prettier code action SHOULD be available because explicitly enabled
+    const prettierAction = codeActions?.find(
+      (action) => action.kind?.value === "source.fixAll.prettier",
+    );
+
+    assert.ok(
+      prettierAction,
+      "Prettier code action should be available when source.fixAll.prettier is explicitly enabled",
+    );
+  });
 });

test-fixtures/test.code-workspace

@@ -68,6 +68,9 @@
     },
     {
       "path": "yarn-pnp-sdk"
+    },
+    {
+      "path": "workspace-explicit-prettier"
     }
   ],
   "settings": {

test-fixtures/workspace-explicit-prettier/.vscode/settings.json

@@ -0,0 +1,8 @@
+{
+    "[javascript]": {
+        "editor.defaultFormatter": "vscode.typescript-language-features"
+    },
+    "editor.codeActionsOnSave": {
+        "source.fixAll.prettier": "always"
+    }
+}

test-fixtures/workspace-explicit-prettier/test.js

@@ -0,0 +1 @@
+const  x   =  {  a: 1, b: 2  }

test-fixtures/workspace/test.js

@@ -0,0 +1 @@
+const  x   =  {  a: 1, b: 2  }