fix(formatter): fix formatting order in codeActionsOnSave

client/tools/formatter.ts

@@ -7,6 +7,8 @@ import {
   ConfigurationChangeEvent,
   languages,
   LogOutputChannel,
+  Range,
+  TextEdit,
   Uri,
   workspace,
 } from "vscode";
@@ -321,6 +323,18 @@ export default class FormatterTool implements ToolInterface {
           ) {
             return [];
           }
+
+          // When source.format.oxc is configured in codeActionsOnSave,
+          // formatting is handled by the onWillSaveTextDocument listener
+          // which runs BEFORE code actions are collected.  Returning a
+          // code action with a command here would run the formatter
+          // AFTER lint fixes, undoing them.
+          const codeActionsOnSave = workspace.getConfiguration("editor", doc)
+            .get<Record<string, string>>("codeActionsOnSave");
+          if (codeActionsOnSave?.["source.format.oxc"]) {
+            return [];
+          }
+
           return [formatCodeAction];
         },
       },
@@ -329,6 +343,53 @@ export default class FormatterTool implements ToolInterface {
       },
     );
 
+    // Apply formatting via onWillSaveTextDocument so that edits are in the
+    // document BEFORE codeActionsOnSave are collected.  This guarantees the
+    // format→lint order when both source.format.oxc and source.fixAll.oxc
+    // are configured in editor.codeActionsOnSave.
+    const onWillSave = workspace.onWillSaveTextDocument(async (event) => {
+      if (
+        configService.vsCodeConfig.enableOxfmt === false ||
+        !this.client
+      ) {
+        return;
+      }
+
+      const codeActionsOnSave = workspace.getConfiguration("editor", event.document)
+        .get<Record<string, string>>("codeActionsOnSave");
+
+      // Only apply formatting via this listener when source.format.oxc is
+      // configured in codeActionsOnSave.
+      if (!codeActionsOnSave?.["source.format.oxc"]) {
+        return;
+      }
+
+      try {
+        const edits = await this.client.sendRequest<
+          { range: { start: { line: number; character: number }; end: { line: number; character: number } }; newText: string }[]
+        >("textDocument/formatting", {
+          textDocument: { uri: event.document.uri.toString() },
+          options: { tabSize: 2, insertSpaces: true },
+        });
+
+        if (edits) {
+          event.waitUntil(Promise.resolve(
+            edits.map((edit) => new TextEdit(
+              new Range(
+                edit.range.start.line,
+                edit.range.start.character,
+                edit.range.end.line,
+                edit.range.end.character,
+              ),
+              edit.newText,
+            )),
+          ));
+        }
+      } catch {
+        // Formatting failed – let the normal formatOnSave or code action handle it
+      }
+    });
+
     outputChannel.info(`Using server binary at: ${binary?.path}`);
 
     const run: Executable = runExecutable(
@@ -386,6 +447,7 @@ export default class FormatterTool implements ToolInterface {
       restartCommand.dispose();
       toggleEnable.dispose();
       formatAction.dispose();
+      onWillSave.dispose();
       onNotificationDispose.dispose();
     };
 

tests/integration/code_actions.spec.ts

@@ -226,8 +226,56 @@ suite("code actions formatter", () => {
     return;
   }
 
-  // TODO: re-enable this test after fixing the underlying issue of code actions on save not being triggered in tests
-  test.skip("code action `source.format.oxc` on editor.codeActionsOnSave", async () => {
+  test("code action `source.format.oxc` is suppressed when configured in codeActionsOnSave", async () => {
+    await workspace.getConfiguration("editor").update("defaultFormatter", "oxc.oxc-vscode");
+    await workspace.getConfiguration("editor").update("codeActionsOnSave", {
+      "source.format.oxc": "always",
+    });
+    await workspace.saveAll();
+    await loadFixture("formatting");
+
+    await sleep(500);
+
+    const fileUri = Uri.joinPath(fixturesWorkspaceUri(), "fixtures", "formatting.ts");
+    await window.showTextDocument(fileUri);
+
+    const codeActions = await commands.executeCommand(
+      "vscode.executeCodeActionProvider",
+      fileUri,
+      new Range(new Position(0, 0), new Position(0, 0)),
+    ) as CodeAction[];
+
+    assert(Array.isArray(codeActions));
+    const formatActions = codeActions.filter((a) => a.kind?.value === "source.format.oxc");
+    strictEqual(formatActions.length, 0, "should return no format code action when source.format.oxc is in codeActionsOnSave");
+  });
+
+  test("code action `source.format.oxc` is returned when NOT configured in codeActionsOnSave", async () => {
+    await workspace.getConfiguration("editor").update("defaultFormatter", "oxc.oxc-vscode");
+    await workspace.getConfiguration("editor").update("codeActionsOnSave", undefined);
+    await workspace.saveAll();
+    await loadFixture("formatting");
+
+    await sleep(500);
+
+    const fileUri = Uri.joinPath(fixturesWorkspaceUri(), "fixtures", "formatting.ts");
+    await window.showTextDocument(fileUri);
+
+    const codeActions = await commands.executeCommand(
+      "vscode.executeCodeActionProvider",
+      fileUri,
+      new Range(new Position(0, 0), new Position(0, 0)),
+    ) as CodeAction[];
+
+    assert(Array.isArray(codeActions));
+    const formatActions = codeActions.filter((a) => a.kind?.value === "source.format.oxc");
+    strictEqual(formatActions.length, 1, "should return format code action when source.format.oxc is NOT in codeActionsOnSave");
+    strictEqual(formatActions[0].title, "Format Document");
+  });
+
+  // TODO: re-enable after fixing the test infrastructure issue where
+  // onWillSaveTextDocument edits are not applied during save in the test environment
+  test.skip("code action `source.format.oxc` on editor.codeActionsOnSave applies formatting on save", async () => {
     await workspace.getConfiguration("editor").update("defaultFormatter", "oxc.oxc-vscode");
     await workspace.getConfiguration("editor").update("codeActionsOnSave", {
       "source.format.oxc": "always",
@@ -239,6 +287,7 @@ suite("code actions formatter", () => {
 
     const fileUri = Uri.joinPath(fixturesWorkspaceUri(), "fixtures", "formatting.ts");
 
+    // Dirty the file by making a small edit
     const range = new Range(new Position(0, 0), new Position(0, 0));
     const edit = new WorkspaceEdit();
     edit.replace(fileUri, range, " ");