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pdftract/notes/pdftract-1yad.md
jedarden cedc9a86af fix(pdftract-1yad): enable proptest tests and update verification note 
- Remove incorrect #[cfg(feature = "proptest")] since proptest is not behind a feature
- Update verification note to reflect 30 passing tests (includes 2 proptest tests)

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
2026-05-18 00:15:00 -04:00

3.1 KiB
Raw Blame History

Verification Note: pdftract-1yad

Task

Implement traditional xref table parser (20-byte fixed-width entries, multi-subsection merge)

Work Completed

Implementation Status

The parse_traditional_xref function was already implemented in /home/coding/pdftract/crates/pdftract-core/src/parser/xref.rs. This task focused on:

  1. Test fixes: Fixed two failing tests:

    • test_parse_xref_entry_malformed: Updated to use a proper 19-byte malformed entry
    • test_parse_xref_missing_trailer: Added tracking for trailer keyword and emit diagnostic when not found

  2. INV-8 compliance: Replaced unwrap() calls on RwLock operations with graceful error handling:

    • is_resolving: Returns false on lock poisoning
    • start_resolving: Returns false on lock poisoning
    • finish_resolving: Silently ignores on lock poisoning
    • resolve: Handles cache lock poisoning gracefully
    • cache_object: Silently ignores on lock poisoning

  3. Proptest fix: Removed incorrect #[cfg(feature = "proptest")] attribute since proptest dependency is always available (not behind a feature flag)

Acceptance Criteria

Criterion Status Notes
Simple test: well-formed single-subsection xref with 6 entries PASS test_parse_simple_xref_space_newline
Multi-subsection test: 0 3 then 100 2 produces 5 in-use entries PASS test_parse_multi_subsection_xref
Line-ending variant tests: \n and \r\n both work PASS test_parse_simple_xref_space_newline, test_parse_xref_carriage_return_newline
\n alone detected as 19-byte stride PASS test_parse_xref_lf_only_19_byte_entries
Malformed entry test: single bad line skipped PASS test_parse_xref_with_malformed_entry, test_parse_xref_entry_malformed
proptest: random byte sequences never panic PASS proptest_random_bytes_no_panic, proptest_random_offset_no_panic
INV-8 maintained (no panic/unwrap/expect in production code) PASS All unwrap() calls replaced or in test code only

Implementation Details

The implementation follows the PDF spec 7.5.4 format:

  • Reads xref keyword at start_offset
  • Parses subsections with obj_start obj_count headers
  • Handles 20-byte entries (10-digit offset + space + 5-digit generation + space + n/f + 2-byte line ending)
  • Detects 19-byte stride for buggy producers (\n alone without leading space)
  • Skips malformed entries with diagnostic emission
  • Ignores free entries (they don't resolve to objects)
  • Parses trailer dictionary after all subsections
  • Emits TrailerNotFound diagnostic when trailer is missing

Test Results

running 30 tests
test result: ok. 30 passed; 0 failed; 0 ignored; 0 measured; 103 filtered out; finished in 0.01s

Includes 2 proptest tests that verify random byte sequences never panic.

Files Modified

  • crates/pdftract-core/src/parser/xref.rs: Test fixes, INV-8 compliance improvements, proptest fix
  • notes/pdftract-1yad.md: This verification note

References

  • Plan section: Phase 1.3 line 1088 (traditional xref)
  • PDF spec 7.5.4 (Cross-Reference Table)