Fix infinite loop when parsing H4–H6 headings#6
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Fix infinite loop when parsing H4–H6 headings#6mohamorui wants to merge 1 commit intolovstudio:mainfrom
mohamorui wants to merge 1 commit intolovstudio:mainfrom
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parse_md() had handlers only for H1–H3. Any line starting with ####,
##### or ###### fell into the paragraph collector, which immediately
broke on lines starting with '#', leaving `i` unchanged. The outer
`while i < len(lines)` then re-processed the same line forever
(100% CPU, no output), which broke conversion of documents using
sub-sub-section headings.
- Extend the section handler to match H3–H6 (`#{3,6}\s+`). Deeper
levels render with the H3 style so their content is preserved
instead of stalling the parser.
- Add a defensive `i += 1` in the paragraph branch so future
unmatched lines (e.g. `#!shebang` or a bare `#`) cannot stall
the loop again.
- Add tests/07-deep-headings.md as a regression guard covering
H3–H6, a table between deep headings, and deep headings with
`&` and inline code.
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Summary
parse_md()had handlers for H1–H3 only. Any line starting with####,#####or######(including most deeply-nested sections in real technical docs) would stall the parser in an infinite loop: the paragraph collector breaks on lines starting with#, soplinesstays empty andiis never advanced. The outerwhile i < len(lines)loop then re-processes the same line forever, pinning one CPU core at 100% with no output. Any Markdown containing an H4 becomes non-convertible.Reproduction
Minimal input that hangs on
main:Observed:
python3 md2pdf.py --input x.md --output x.pdf— process runs indefinitely at 100% CPU, never produces a PDF. Triggered in practice on a 1143-line SPEC where the first####heading is on line 212.Fix
lovstudio-any2pdf/scripts/md2pdf.py— extend the section handler to match#{3,6}\s+so H3–H6 share the H3 style (ReportLab has no H4–H6 styles defined here; deeper levels are rendered rather than dropped).lovstudio-any2pdf/scripts/md2pdf.py— defensivei += 1fallback in the paragraph branch, so any future unmatched line (#!shebang, bare#, unknown marker) cannot stall the loop again.tests/07-deep-headings.md— regression test covering H3–H6, a table between deep headings, and deep headings containing&and inline code.Net diff: +9/-3 in
md2pdf.py, plus one new test file.Verification
Ran on macOS 15 with Python 3.9 and reportlab 4.4.10.
#### Headingreproducertests/01–06× 4 themes (existing)tests/07-deep-headings× 4 themes (new)pdftotextextraction of new testTest plan
python -m py_compile)tests/01–06still produce PDFs acrosswarm-academic/nord-frost/tufte/github-lighttests/07-deep-headings.mdproduces PDFs across the same themes