pdftract/notes/pdftract-2vd1y.md

pdftract-2vd1y — JavaScript Presence Detection

Summary

The JavaScript detection module (crates/pdftract-core/src/javascript.rs) already implements complete JavaScript presence detection. All acceptance criteria pass.

Implementation Verified

Public API

• contains_javascript(catalog, pages, acroform, resolver) -> bool — lines 140-200
• detect_javascript(catalog, pages, resolver) -> (Vec<JavascriptAction>, Vec<Diagnostic>) — lines 42-96

Detection Sites (all covered)

1. Catalog /OpenAction — lines 148-153
2. Catalog /AA — lines 155-160
3. Page /AA — lines 164-169
4. AcroForm field /AA — lines 192-197 (recursive walk via walk_field_for_js)
5. Annotation /A or /AA — lines 171-189

Key Features Verified

• /JavaScript and /JS spellings — line 237: s_name == "JavaScript" || s_name == "JS"
• /Next chaining — action_contains_js recurses through /Next (line 244-247)
• Cycle protection — visited: HashSet<ObjRef> prevents infinite loops (line 146, 215-218)
• Field tree recursion — walk_field_for_js tracks field_visited separately (lines 336-386)

Test Results

16 tests run: 16 passed
- test_contains_javascript_catalog_openaction: PASS
- test_contains_javascript_catalog_aa: PASS
- test_contains_javascript_page_aa: PASS
- test_contains_javascript_acroform_field_aa: PASS
- test_contains_javascript_annotation_with_action: PASS
- test_contains_javascript_empty: PASS
- test_contains_javascript_next_chain: PASS
- test_contains_javascript_cycle_protection: PASS
- test_contains_javascript_recognizes_js_short_form: PASS
- test_contains_javascript_non_javascript_action: PASS
- test_detect_javascript_empty: PASS
- TH-04 integration tests (4): PASS

Acceptance Criteria Status

Criterion	Status	Test
/OpenAction /S /JavaScript → true	PASS	test_contains_javascript_catalog_openaction
Page /AA /O /S /JS → true	PASS	test_contains_javascript_page_aa
Form field /AA /K /S /JavaScript → true	PASS	test_contains_javascript_acroform_field_aa
Annotation /A /S /JavaScript → true	PASS	test_contains_javascript_annotation_with_action
No JS → false	PASS	test_contains_javascript_empty
/Next-chained action → true	PASS	test_contains_javascript_next_chain
Cyclic /Next → no infinite loop	PASS	test_contains_javascript_cycle_protection

Code Quality

• Documentation: Clear module-level docs stating "pdftract NEVER executes embedded JavaScript"
• Error handling: Resolves indirect objects safely, returns false on resolution failure
• Performance: Early exit on first JS detection in contains_javascript
• Safety: Separate visited sets for action chains vs field tree traversal

Retrospective

What worked

• The implementation was already complete with comprehensive test coverage
• Code follows the pattern described in the bead (recursive walker, cycle protection)
• Both /JavaScript and /JS spellings are recognized

What didn't

• No issues encountered; implementation is complete

Surprise

• The module already had two functions: contains_javascript (bool) and detect_javascript (detailed actions). The bead asked for the boolean return which already exists.

Reusable pattern

• The cycle protection pattern (visited: HashSet<ObjRef>) is reusable for any recursive PDF structure walk
• The separate action_visited and field_visited sets in walk_field_for_js shows how to handle nested recursive structures with different cycle domains