fix: use ConfigError, guard null status, skip empty output dirs

Author: pullfrog[bot]

packages/shared/src/config/output/__tests__/postprocess.test.ts

@@ -1,11 +1,17 @@
+import fs from 'node:fs';
+
 import { sync } from 'cross-spawn';
 import { vi } from 'vitest';
 
+import { ConfigError } from '../../../error';
 import { postprocessOutput } from '../postprocess';
 
 vi.mock('cross-spawn');
+vi.mock('node:fs');
 
 const mockSync = vi.mocked(sync);
+const mockExistsSync = vi.mocked(fs.existsSync);
+const mockReaddirSync = vi.mocked(fs.readdirSync);
 
 const baseConfig = {
   path: '/output',
@@ -17,13 +23,39 @@ const noopPostProcessors = {};
 describe('postprocessOutput', () => {
   beforeEach(() => {
     vi.clearAllMocks();
+    mockExistsSync.mockReturnValue(true);
+    mockReaddirSync.mockReturnValue(['index.ts'] as any);
   });
 
   it('should not call sync when postProcess is empty', () => {
     postprocessOutput(baseConfig, noopPostProcessors, '');
     expect(mockSync).not.toHaveBeenCalled();
   });
 
+  it('should not call sync when output directory does not exist', () => {
+    mockExistsSync.mockReturnValue(false);
+
+    postprocessOutput(
+      { ...baseConfig, postProcess: [{ args: ['{{path}}'], command: 'prettier' }] },
+      noopPostProcessors,
+      '',
+    );
+
+    expect(mockSync).not.toHaveBeenCalled();
+  });
+
+  it('should not call sync when output directory is empty', () => {
+    mockReaddirSync.mockReturnValue([] as any);
+
+    postprocessOutput(
+      { ...baseConfig, postProcess: [{ args: ['{{path}}'], command: 'prettier' }] },
+      noopPostProcessors,
+      '',
+    );
+
+    expect(mockSync).not.toHaveBeenCalled();
+  });
+
   it('should call sync with command and resolved args', () => {
     mockSync.mockReturnValue({ error: undefined, status: 0 } as any);
 
@@ -48,7 +80,20 @@ describe('postprocessOutput', () => {
     expect(mockSync).toHaveBeenCalledWith('prettier', ['/my/output', '--write']);
   });
 
-  it('should throw when the process fails to spawn (e.g., ENOENT)', () => {
+  it('should throw ConfigError when the process fails to spawn (e.g., ENOENT)', () => {
+    const spawnError = new Error('spawnSync oxfmt ENOENT');
+    mockSync.mockReturnValue({ error: spawnError, status: null } as any);
+
+    expect(() =>
+      postprocessOutput(
+        { ...baseConfig, postProcess: [{ args: ['{{path}}'], command: 'oxfmt' }] },
+        noopPostProcessors,
+        '',
+      ),
+    ).toThrow(ConfigError);
+  });
+
+  it('should include the error message when the process fails to spawn', () => {
     const spawnError = new Error('spawnSync oxfmt ENOENT');
     mockSync.mockReturnValue({ error: spawnError, status: null } as any);
 
@@ -77,7 +122,19 @@ describe('postprocessOutput', () => {
     ).toThrow('Post-processor "My Formatter" failed to run: spawnSync my-formatter ENOENT');
   });
 
-  it('should throw when the process exits with a non-zero status code', () => {
+  it('should throw ConfigError when the process exits with a non-zero status code', () => {
+    mockSync.mockReturnValue({ error: undefined, status: 1, stderr: Buffer.from('') } as any);
+
+    expect(() =>
+      postprocessOutput(
+        { ...baseConfig, postProcess: [{ args: ['{{path}}'], command: 'prettier' }] },
+        noopPostProcessors,
+        '',
+      ),
+    ).toThrow(ConfigError);
+  });
+
+  it('should include exit code in error message', () => {
     mockSync.mockReturnValue({ error: undefined, status: 1, stderr: Buffer.from('') } as any);
 
     expect(() =>
@@ -105,6 +162,18 @@ describe('postprocessOutput', () => {
     ).toThrow('Post-processor "biome" exited with code 2:\nerror: file not found');
   });
 
+  it('should not throw when the process is killed by a signal (null status)', () => {
+    mockSync.mockReturnValue({ error: undefined, signal: 'SIGTERM', status: null } as any);
+
+    expect(() =>
+      postprocessOutput(
+        { ...baseConfig, postProcess: [{ args: ['{{path}}'], command: 'prettier' }] },
+        noopPostProcessors,
+        '',
+      ),
+    ).not.toThrow();
+  });
+
   it('should skip unknown string preset processors', () => {
     postprocessOutput({ ...baseConfig, postProcess: ['unknown-preset'] }, noopPostProcessors, '');
     expect(mockSync).not.toHaveBeenCalled();

packages/shared/src/config/output/postprocess.ts

@@ -1,6 +1,10 @@
+import fs from 'node:fs';
+
 import colors from 'ansi-colors';
 import { sync } from 'cross-spawn';
 
+import { ConfigError } from '../../error';
+
 type Output = {
   /**
    * The absolute path to the output folder.
@@ -50,6 +54,15 @@ export function postprocessOutput(
   postProcessors: Record<string, PostProcessor>,
   jobPrefix: string,
 ): void {
+  if (!config.postProcess.length) {
+    return;
+  }
+
+  // skip post-processing when the output directory doesn't exist or is empty
+  if (!fs.existsSync(config.path) || fs.readdirSync(config.path).length === 0) {
+    return;
+  }
+
   for (const processor of config.postProcess) {
     const resolved = typeof processor === 'string' ? postProcessors[processor] : processor;
 
@@ -63,16 +76,16 @@ export function postprocessOutput(
     const result = sync(resolved.command, args);
 
     if (result.error) {
-      throw new Error(`Post-processor "${name}" failed to run: ${result.error.message}`);
+      throw new ConfigError(`Post-processor "${name}" failed to run: ${result.error.message}`);
     }
 
-    if (result.status !== 0) {
+    if (result.status !== null && result.status !== 0) {
       let message = `Post-processor "${name}" exited with code ${result.status}`;
       const stderr = result.stderr?.toString().trim();
       if (stderr) {
         message += `:\n${stderr}`;
       }
-      throw new Error(message);
+      throw new ConfigError(message);
     }
   }
 }