feat: simplifying towards docling-parse v5

[PeterStaar-IBM]

Summary of Changes

1. ✅ Updated pyproject.toml

• Changed docling-parse dependency to reference PR fix: updated the font-parsing docling-parse#193 branch: dev/prepare-for-v5

2. ✅ Backend Consolidation Complete

Files Deleted:

• docling/backend/docling_parse_backend.py (V1)
• docling/backend/docling_parse_v2_backend.py (V2)
• tests/test_backend_docling_parse.py (V1 tests)
• tests/test_backend_docling_parse_v2.py (V2 tests)

Files Renamed:

• docling/backend/docling_parse_v4_backend.py → docling/backend/docling_parse_backend.py
• tests/test_backend_docling_parse_v4.py → tests/test_backend_docling_parse.py

Classes Renamed:

• DoclingParseV4DocumentBackend → DoclingParseDocumentBackend
• DoclingParseV4PageBackend → DoclingParsePageBackend

3. ✅ Backward Compatibility Maintained

Updated pipeline_options.py:

• Added new enum value: PdfBackend.DOCLING_PARSE = "docling_parse"
• Kept deprecated values: DLPARSE_V1, DLPARSE_V2, DLPARSE_V4 (marked as deprecated)
• Added normalize_pdf_backend() function that:
  • Automatically maps deprecated values to DOCLING_PARSE
  • Emits DeprecationWarning when deprecated values are used

4. ✅ Updated All References

Core Files:

• docling/cli/main.py - Updated imports, backend selection logic, and default value
• docling/document_converter.py - Updated imports and default backend
• docling/datamodel/pipeline_options.py - Added enum and normalization function

Test Files:

• tests/test_backend_docling_parse.py - Updated imports and class names
• tests/test_options.py - Updated imports and removed V2/V4 from test loop
• tests/test_e2e_ocr_conversion.py - Updated imports
• tests/test_pdf_password.py - Updated imports and class names

Documentation/Examples:

• docs/examples/batch_convert.py - Updated imports and class names

Migration Path for Users

Users with existing code using deprecated backends will:

1. See a DeprecationWarning when using DLPARSE_V1, DLPARSE_V2, or DLPARSE_V4
2. Have their code continue to work (mapped automatically to DOCLING_PARSE)
3. Be guided to update to PdfBackend.DOCLING_PARSE

[mergify]

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• title ~= ^(fix|feat|docs|style|refactor|perf|test|build|ci|chore|revert)(?:\(.+\))?(!)?:

[github-actions]

✅ DCO Check Passed

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[codecov]

Codecov Report

❌ Patch coverage is 91.20879% with 8 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
docling/backend/docling_parse_backend.py	92.00%	6 Missing ⚠️
docling/datamodel/pipeline_options.py	81.81%	2 Missing ⚠️

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