When Tesseract cannot find its 'hocr' or 'txt' config files in the
tessdata configs/ directory, it prints "read_params_file: Can't open"
warnings, exits 0, and produces no output. OCRmyPDF then crashed with a
confusing FileNotFoundError on the missing hOCR file (issue #1687).
Promote read_params_file warnings to TesseractConfigError with guidance
on the likely cause, and verify the expected output file exists after
Tesseract claims success as defense-in-depth for other silent-failure
modes.
Split ocrmypdf.subprocess/__init__.py into three private submodules by
concern (_run, _version, _check) and reduce __init__ to re-exports.
Introduce ocrmypdf._exec._probe.ToolProbe to centralize the version()/
available() pattern each tool module was reimplementing, so the "is this
tool installed and suitable?" question is cleanly distinct from the
pure, picklable functions that do the work.
Also replace the ghostscript module-import log.addFilter() side effect
with an idempotent _ensure_log_filter_installed() called at the top of
each work function, so the DuplicateFilter is present in subprocess
workers without relying on import-time ordering.
Public API of ocrmypdf.subprocess is unchanged.
- Add new '--output-type auto' option (now the default) that produces
best-effort PDF/A without requiring Ghostscript
- When verapdf is available, use speculative PDF/A conversion
- Without verapdf, pass through as PDF/A if safe (input claims PDF/A
or --force-ocr was used), otherwise output as regular PDF
- Make Ghostscript check conditional - only required for pdfa* output types
- Update soft error tests to explicitly use --output-type pdfa since they
exercise Ghostscript failure modes
- Fix Tesseract OSD error handling to check both stdout and stderr for
known non-fatal messages like "Too few characters"
Instead of setting OMP_THREAD_LIMIT in the parent process's environment,
calculate the thread limit in the validate hook and pass it through to
Tesseract subprocess calls via the env parameter. This avoids polluting
the parent process's environment while still controlling Tesseract's
thread usage.
Replace integer-based thresholding parameter with ThresholdingMethod
enum for improved type safety. The CLI still accepts the same string
values (auto, otsu, adaptive-otsu, sauvola) but internally uses a
strongly-typed enum. This makes the code more maintainable and catches
type errors at development time.
The parameters are equivalent but the latter is better named. Since
Python 3.6 doesn't support text= we use our wrapper to add it in that
place.
This is for subprocess.run.
James R. Barlow
Kian-Meng AngandGitHub