fix: warn on post-processor non-zero exit instead of throwing

Post-processors like ESLint and Oxfmt can exit non-zero for non-fatal
reasons (e.g. all files ignored, no matching files). Previously these
were silently swallowed; the prior commit made them throw ConfigError
which broke examples:generate for openapi-ts-nestjs and openapi-ts-openai.

Now non-zero exits log a warning and continue processing. Spawn
failures (ENOENT) still throw as intended by the original fix.

Author: pullfrog[bot]

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

@@ -122,44 +122,62 @@ describe('postprocessOutput', () => {
     ).toThrow('Post-processor "My Formatter" failed to run: spawnSync my-formatter ENOENT');
   });
 
-  it('should throw ConfigError when the process exits with a non-zero status code', () => {
+  it('should warn when the process exits with a non-zero status code', () => {
     mockSync.mockReturnValue({ error: undefined, status: 1, stderr: Buffer.from('') } as any);
+    const warnSpy = vi.spyOn(console, 'warn').mockImplementation(() => {});
 
-    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);
+    postprocessOutput(
+      { ...baseConfig, postProcess: [{ args: ['{{path}}'], command: 'prettier' }] },
+      noopPostProcessors,
+      '',
+    );
 
-    expect(() =>
-      postprocessOutput(
-        { ...baseConfig, postProcess: [{ args: ['{{path}}'], command: 'prettier' }] },
-        noopPostProcessors,
-        '',
-      ),
-    ).toThrow('Post-processor "prettier" exited with code 1');
+    expect(warnSpy).toHaveBeenCalledWith(
+      expect.stringContaining('Post-processor "prettier" exited with code 1'),
+    );
+    warnSpy.mockRestore();
   });
 
-  it('should include stderr output in error message when process fails', () => {
+  it('should include stderr in warning when process exits with non-zero status', () => {
     mockSync.mockReturnValue({
       error: undefined,
       status: 2,
       stderr: Buffer.from('error: file not found'),
     } as any);
+    const warnSpy = vi.spyOn(console, 'warn').mockImplementation(() => {});
 
-    expect(() =>
-      postprocessOutput(
-        { ...baseConfig, postProcess: [{ args: ['{{path}}'], command: 'biome' }] },
-        noopPostProcessors,
-        '',
-      ),
-    ).toThrow('Post-processor "biome" exited with code 2:\nerror: file not found');
+    postprocessOutput(
+      { ...baseConfig, postProcess: [{ args: ['{{path}}'], command: 'biome' }] },
+      noopPostProcessors,
+      '',
+    );
+
+    expect(warnSpy).toHaveBeenCalledTimes(1);
+    const warnArg = warnSpy.mock.calls[0]![0] as string;
+    expect(warnArg).toContain('Post-processor "biome" exited with code 2:');
+    expect(warnArg).toContain('error: file not found');
+    warnSpy.mockRestore();
+  });
+
+  it('should continue processing after a non-zero exit code', () => {
+    mockSync
+      .mockReturnValueOnce({ error: undefined, status: 1, stderr: Buffer.from('') } as any)
+      .mockReturnValueOnce({ error: undefined, status: 0 } as any);
+    vi.spyOn(console, 'warn').mockImplementation(() => {});
+
+    postprocessOutput(
+      {
+        ...baseConfig,
+        postProcess: [
+          { args: ['{{path}}'], command: 'first' },
+          { args: ['{{path}}'], command: 'second' },
+        ],
+      },
+      noopPostProcessors,
+      '',
+    );
+
+    expect(mockSync).toHaveBeenCalledTimes(2);
   });
 
   it('should not throw when the process is killed by a signal (null status)', () => {

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

@@ -85,7 +85,7 @@ export function postprocessOutput(
       if (stderr) {
         message += `:\n${stderr}`;
       }
-      throw new ConfigError(message);
+      console.warn(`${jobPrefix}${colors.yellow(`⚠️ ${message}`)}`);
     }
   }
 }