Track unresolved upstream Apache PDFBox 4.0 parity risks

[erikbra]

Purpose

Track unresolved Apache PDFBox issues that may affect PdfBox.Net parity, without implementing .NET-only fixes ahead of upstream Apache PDFBox.

This issue is an umbrella for grouped tracking issues. The intent is to keep the known risks visible, add fixtures where useful, and port/adapt upstream fixes once Apache PDFBox has accepted a direction.

Policy

• Do not mirror every Apache JIRA issue as a PdfBox.Net issue.
• Do not implement speculative fixes that get ahead of upstream unless the issue is clearly .NET/backend-specific.
• Prefer parity fixtures and Java-vs-.NET comparisons for rendering/text/parser behavior.
• When current Apache trunk already contains a fix, verify the exact upstream change before porting it.

Upstream groups

• Parser and xref recovery: PDFBOX-5032, PDFBOX-6201.
• Large-file and memory behavior: PDFBOX-6175, PDFBOX-5034, PDFBOX-4690.
• Text extraction: PDFBOX-2138, PDFBOX-2532, PDFBOX-6188.
• Rendering/forms/masks: PDFBOX-2359, PDFBOX-5953, PDFBOX-6024.
• Fonts/glyphs/subsetting: PDFBOX-6175, PDFBOX-2578, PDFBOX-3759, PDFBOX-4951.
• Signatures: PDFBOX-3699.
• Structure/collection model: PDFBOX-4414, PDFBOX-5172.
• COS object robustness: PDFBOX-5731, PDFBOX-6200.
• Optional utilities: PDFBOX-2124.

Acceptance criteria

• Each grouped issue links the relevant Apache JIRA tickets.
• Each grouped issue states whether the next action is watch-upstream, add fixture, or port a confirmed upstream change.
• Closed only when the grouped issues are resolved, intentionally deferred, or superseded by more specific parity work.

[erikbra]

Created grouped tracking issues:

• Track parser and xref recovery parity with upstream PDFBox #651 - Parser and xref recovery parity
• Track large-file, cache, and rendering memory parity with upstream PDFBox #652 - Large-file, cache, and rendering memory parity
• Add parity fixtures for upstream text extraction issues #653 - Text extraction parity fixtures
• Add parity fixtures for upstream rendering, form, and mask issues #654 - Rendering, form, and mask parity fixtures
• Track font cache, Base 14 matching, subsetting, and glyph parity #655 - Font cache, Base 14 matching, subsetting, and glyph parity
• Track signature certification parity with upstream PDFBox #656 - Signature certification parity
• Track structure-tree API cleanup and portable collection model parity #657 - Structure-tree API cleanup and portable collection model parity
• Port Apache weak COSName cache semantics #658 - COS name cache and update-state graph robustness parity
• Track optional barcode scanning utility request after upstream direction #659 - Optional barcode scanning utility request after upstream direction