Cover write_geotiff_gpu CPU-fallback codecs (#1706)#1709
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brendancol merged 1 commit intoMay 12, 2026
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Pull request overview
Adds targeted regression tests to cover write_geotiff_gpu compression modes that route through CPU fallback branches (or CPU-only implementations), ensuring both round-trip pixel fidelity and correct on-disk TIFF Compression tag emission for interoperability.
Changes:
- Add a new GPU-gated test module covering
lzw,packbits,lz4,lerc, andjpeg2000/j2kthroughwrite_geotiff_gpu, including Compression-tag pinning via IFD parsing. - Add cross-backend decoded-pixel parity checks for lossless CPU-fallback codecs (
lzw,packbits) and dispatch coverage forto_geotiff(gpu=True, ...). - Update sweep test-coverage state metadata to record the newly closed coverage gap.
Reviewed changes
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| File | Description |
|---|---|
xrspatial/geotiff/tests/test_gpu_writer_cpu_fallback_codecs_2026_05_12.py |
New GPU-gated tests for CPU-fallback codec routing + TIFF Compression tag pinning + limited CPU/GPU parity checks. |
.claude/sweep-test-coverage-state.csv |
Records sweep pass metadata indicating the new coverage for issue #1706. |
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The GPU writer documents nine compression= modes; only four (none, deflate, zstd, jpeg) had direct round-trip coverage. The remaining five (lzw, packbits, lz4, lerc, jpeg2000/j2k) route through dedicated branches in gpu_compress_tiles with CPU fallbacks that shipped without targeted tests. 17 new tests, all passing on a GPU host: * lzw, packbits, lz4: round-trip + TIFF Compression tag pin on uint16 input. * lerc: lossless round-trip on float32 and uint16 + tag pin. * jpeg2000: uint8 single-band + RGB multi-band lossless round-trip, j2k-alias parity, tag pin (skipif glymur missing). * GPU-vs-CPU writer pixel parity for lzw/packbits. * to_geotiff(gpu=True, compression=lzw/packbits) dispatcher thread-through. Mutation tests confirm sensitivity: swapping lzw bytes to zstd in cpu_compress and lerc bytes to deflate in lerc_compress both flip round-trip tests red. State CSV updated with pass-11 notes.
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Closes #1706.
Summary
The GPU writer documents nine
compression=modes; only four (none,deflate,zstd,jpeg) had direct round-trip tests. The remaining five (lzw,packbits,lz4,lerc,jpeg2000/j2k) route through dedicated branches ingpu_compress_tiles(_gpu_decode.py:2974-3019) with CPU fallbacks (lerc_compress,jpeg2000_compress,cpu_compress) and had zero direct tests viawrite_geotiff_gpu. A regression in routing, tag-wiring, or fallback dispatch would ship silently because the internal reader uses the same compression-tag table.Source unchanged; test-only addition.
Tests added
xrspatial/geotiff/tests/test_gpu_writer_cpu_fallback_codecs_2026_05_12.py-- 17 tests, all passing on a GPU host:lzw,packbits,lz4: round-trip + TIFF Compression tag pin onuint16input.lerc: lossless round-trip onfloat32anduint16+ tag pin (skipiflercmissing).jpeg2000:uint8single-band + RGB multi-band lossless round-trip,j2k-alias parity, tag pin (skipifglymurmissing).lzw/packbits.to_geotiff(gpu=True, compression='lzw'/'packbits')dispatcher thread-through.Test plan
test_gpu_writer_compression_modes_2026_05_11.pystill passes alongsidelzwbytes tozstdincpu_compress; swaplercbytes todeflateinlerc_compress; both flip round-trip tests red)Sweep metadata
Filed via the deep-sweep test-coverage workflow (pass 11). State CSV updated to reflect the new coverage.