Fix page_range stopping at page 32 when start >= 30

[Copilot]

The page_range parameter stops prematurely at page 32 when the range starts from page 30 or higher. For example, page_range=(30, 35) extracts only pages 30-32 instead of 30-35.

Root Cause

The drain loop uses a hardcoded batch_size = 32 to pull processed pages from the output queue. This creates an effective ceiling at page_no 31 (page 32 in 1-indexed terms) when combined with the page range filtering logic.

Changes

Core fix:

• Changed batch_size: int = 32 to batch_size: int = total_pages in the drain loops
  • docling/pipeline/standard_pdf_pipeline.py:548
  • docling/experimental/pipeline/threaded_layout_vlm_pipeline.py:255

Tests:

• Added tests/test_page_range_bug.py with coverage for:
  • Ranges starting at page 30+
  • Ranges entirely beyond page 32
  • Single-page extraction at boundaries (pages 32, 33)
  • Range crossing the page 32 boundary

# Previously failed - only got pages 30-32
result = converter.convert(pdf, page_range=(30, 35))
assert len(result.pages) == 6  # Now correctly extracts all 6 pages

# Verify page_no values are correct (0-indexed)
assert [p.page_no for p in result.pages] == [29, 30, 31, 32, 33, 34]

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Original prompt

---

This section details on the original issue you should resolve

<issue_title>page_range parameter stops prematurely at page 32 when starting from page 30+</issue_title>
<issue_description>### Bug
The page_range parameter in DocumentConverter.convert() does not properly extract the full requested range when the range spans into the 30s-40s region. The conversion prematurely stops at page 32 instead of continuing to the specified end page.

Pattern observed:

• page_range=(1, 45) → Works correctly, extracts pages 1-45
• page_range=(30, 35) → Stops at page 32, extracts pages 30-32 instead of 30-35
• page_range=(30, 45) → Stops at page 32, extracts pages 30-32 instead of 30-45

This suggests the issue occurs when:

1. Start page is 30 or higher, AND
2. The range is requested to go beyond page 32
3. Or maybe related to the number of pages
4. Suspected a sys.maxsize issue, but nah

The conversion appears to stop at the end of page 32, regardless of the requested end page.

Steps to reproduce

1. Use a PDF with at least 50 pages
2. Test these page ranges:

from docling.document_converter import DocumentConverter

converter = DocumentConverter()

# Works fine
result1 = converter.convert("test.pdf", page_range=(1, 45)).document.export_to_markdown()
print(result1)
# Manually checking the final lines' content in the PDF file

# Fails - stops at page 32
result2 = converter.convert("test.pdf", page_range=(30, 35)).document.export_to_markdown()
print(result2)
# Manually checking the final lines' content in the PDF file

# Fails - stops at page 32
result3 = converter.convert("test.pdf", page_range=(30, 45)).document.export_to_markdown()
print(result3)
# Manually checking the final lines' content in the PDF file

Environment

Python 3.11.13
UV for package management
docling=2.56.1

Don't hesitate to ask for extra information/context :)</issue_description>

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Comments on the Issue (you are @copilot in this section)

• Fixes page_range parameter stops prematurely at page 32 when starting from page 30+ #2655

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