Stirling-Tools/Stirling-PDF · error · Error

One or both documents have no pages.

Error message

One or both documents have no pages.

What it means

Thrown in the compare handler when Math.max(basePages, compPages) === 0, i.e. both PDFs report zero pages. pdfjs loaded both documents (no password error) but found no renderable pages. This rejects the comparison because there is nothing to compare; a page-count mismatch alone only produces a warning, but zero-on-both is fatal.

Source

Thrown at frontend/editor/src/core/workers/pixelCompareWorker.ts:439

        getDocument(loaderOpts(baseBuffer)).promise,
        getDocument(loaderOpts(comparisonBuffer)).promise,
      ]);

      const basePages = baseDoc.numPages;
      const compPages = compDoc.numPages;
      const sharedPages = Math.min(basePages, compPages);

      if (basePages !== compPages) {
        warnings.push(
          formatWarning(warningTemplates.pageCountMismatch, {
            base: basePages,
            comparison: compPages,
            shared: sharedPages,
          }),
        );
      }
      if (Math.max(basePages, compPages) === 0) {
        throw new Error(warningTemplates.noPages);
      }

      // Walk every page in the longer document. Pages past the shorter document's length
      // are processed one-sided: the missing side is rendered blank and the whole present
      // side is treated as a diff.
      const totalPages = Math.max(basePages, compPages);
      const pageNumbers = Array.from({ length: totalPages }, (_, i) => i + 1);
      const hwThreads = self.navigator?.hardwareConcurrency ?? 4;
      const defaultConcurrency = Math.max(2, Math.min(8, hwThreads - 1));
      const poolSize = Math.max(
        1,
        Math.min(concurrency ?? defaultConcurrency, totalPages),
      );

      let totalDiffPixels = 0;
      let totalPixelsCount = 0;
      let pagesWithChanges = 0;

View on GitHub (pinned to 9ef20dcab8)

Solutions

1. Validate each file's page count (numPages > 0) before queuing the comparison.
2. Reject empty/corrupt PDFs at upload with a clear message instead of starting the worker.
3. Confirm MIME type is application/pdf and that pdfjs reports a positive numPages.
4. If only one PDF is empty, treat the comparison as fully-different rather than failing.

Example fix

// before
if (Math.max(basePages, compPages) === 0) {
  throw new Error(warningTemplates.noPages);
}

// after
if (basePages === 0 && compPages === 0) {
  throw new Error("Both documents have no pages. Select valid PDFs containing at least one page.");
}
if (Math.max(basePages, compPages) === 0) {
  throw new Error(warningTemplates.noPages);
}

function hasPages(doc: PDFDocumentProxy): boolean {
  return typeof doc.numPages === "number" && doc.numPages > 0;
}

if (!hasPages(baseDoc) && !hasPages(compDoc)) {
  throw new Error("Both documents have no pages. Select PDFs with at least one page.");
}

const hasPages = (doc: PDFDocumentProxy | null): doc is PDFDocumentProxy =>
  !!doc && typeof doc.numPages === "number" && doc.numPages > 0;

When it happens

Trigger: Both inputs are valid PDF files with empty page trees (e.g. a PDF container with no pages); corrupt PDFs that parse but expose numPages=0; a non-PDF file mislabeled and partially parsed to 0 pages.

Common situations: User selects placeholder/empty PDFs; a generator emitted a valid header but no page objects; one of the inputs is actually an image or other format that pdfjs loaded as 0 pages.

Related errors

• File ${file.name} appears to be corrupted
• Unexpected trailing input
• Invalid scale ratio: ${ratio}
• Invalid real-world distance (must be positive)
• No team resolved yet

AI-assisted analysis of Stirling-Tools/Stirling-PDF@9ef20dcab8 (2026-08-13). Data as JSON: /api/errors/93376b112d27b3c4. Report an issue: GitHub.