fix(split): retry page writes regardless of path words in errors

src/core/infrastructure/adapters/split/PDFSplitter.ts

@@ -12,6 +12,16 @@ import { WORKER_CONFIG } from '../../config/worker.config.js';
 /** A rendered page, held in memory until it is written to the split directory. */
 type RenderedPage = Omit<PageInfo, 'imagePath'> & { content: Buffer };
 
+/** PDF errors that a retry cannot fix: the document itself is protected or invalid. */
+function isRetryablePdfError(error: Error): boolean {
+  const message = error.message.toLowerCase();
+  return !(
+    message.includes('password') ||
+    message.includes('encrypted') ||
+    message.includes('invalid pdf')
+  );
+}
+
 /**
  * PDF splitter implementation using pdf-to-png-converter.
  *
@@ -161,6 +171,7 @@ export class PDFSplitter implements ISplitter {
     const taskDir = ImagePathUtil.getTaskDir(taskId);
 
     try {
+      // Retry whatever the error says: its message embeds the output path, which can hold any word.
       return await this.withRetry(async () => {
         await fs.mkdir(taskDir, { recursive: true });
 
@@ -171,7 +182,7 @@ export class PDFSplitter implements ISplitter {
           pages.push({ page, pageSource, imagePath });
         }
         return pages;
-      }, 'write page images');
+      }, 'write page images', () => true);
     } catch (error) {
       throw new Error(`Failed to write split images to ${taskDir}: ${(error as Error).message}`);
     }
@@ -182,11 +193,13 @@ export class PDFSplitter implements ISplitter {
    *
    * @param operation - Async operation to retry
    * @param operationName - Name for logging
+   * @param isRetryable - Whether a failure is worth another attempt (default: PDF errors)
    * @returns Operation result
    */
   private async withRetry<T>(
     operation: () => Promise<T>,
-    operationName: string
+    operationName: string,
+    isRetryable: (error: Error) => boolean = isRetryablePdfError
   ): Promise<T> {
     const maxRetries = WORKER_CONFIG.splitter.maxRetries;
     const baseDelay = WORKER_CONFIG.splitter.retryDelayBase;
@@ -199,14 +212,7 @@ export class PDFSplitter implements ISplitter {
       } catch (error) {
         lastError = error as Error;
 
-        // Check for non-retryable errors
-        const errorMessage = lastError.message.toLowerCase();
-        if (
-          errorMessage.includes('password') ||
-          errorMessage.includes('encrypted') ||
-          errorMessage.includes('invalid pdf')
-        ) {
-          // Don't retry for these errors
+        if (!isRetryable(lastError)) {
           throw lastError;
         }
 

src/core/infrastructure/adapters/split/__tests__/PDFSplitter.test.ts

@@ -272,6 +272,32 @@ describe('PDFSplitter', () => {
       expect(pdfToPng).toHaveBeenCalledTimes(1);
     });
 
+    it.each(['password', 'encrypted', 'invalid pdf'])(
+      'should retry a failed write when the output path contains "%s"',
+      async (word) => {
+        const target = path.join('/data', word, 'page-1.png');
+        vi.mocked(fs.writeFile).mockRejectedValueOnce(systemError('EBUSY', 'open', target));
+
+        const result = await splitter.split(task);
+
+        expect(result.totalPages).toBe(1);
+        expect(fs.writeFile).toHaveBeenCalledTimes(2);
+      }
+    );
+
+    it('should fail without writing any page when one has no image', async () => {
+      vi.mocked(pdfToPng).mockResolvedValue([
+        { path: '', name: 'temp-1.png', pageNumber: 1, content: Buffer.from('png-1') },
+        { path: '', name: 'temp-2.png', pageNumber: 2 },
+      ] as any);
+
+      const failure = splitter.split(task);
+
+      await expect(failure).rejects.toThrow('Failed to split PDF document.pdf');
+      await expect(failure).rejects.toThrow('PDF conversion produced no image for page 2');
+      expect(fs.writeFile).not.toHaveBeenCalled();
+    });
+
     it('should not blame the source when writing a page keeps failing, even if it is ENOENT', async () => {
       const target = path.join(splitDir, 'page-1.png');
       vi.mocked(fs.writeFile).mockRejectedValue(systemError('ENOENT', 'open', target));