fix: Make write_cog refuse or apply every option it is given

[kylebarron]

Note

This PR was written by Claude (Claude Code), not by @kylebarron.

Follow-up to #74. Reviewing #74 turned up other ways write_cog can write a fixture without an option it was given. GDAL only logs a warning when it ignores a creation option, and the generators never show rasterio's log, so these failures are silent.

Changes

• A predictor with a codec that can't use it now raises ValueError. GDAL only writes a predictor for DEFLATE, LZW and ZSTD. JPEG, WEBP, LERC and PACKBITS drop it with a logged warning. LZMA drops it with no warning at all: GDAL's option check lists LZMA as taking a predictor (gtiffdataset_write.cpp), but GTIFFSupportsPredictor, which writes the tag, leaves it out. GDAL master is the same.
• nodata is respected. With the default nodata_type="nodata", a nodata you passed was overwritten with 0. Now 0 is only the default.
• scale and offset apply independently. Before, they were only applied when both were given.
• Removed tiled=True and copy_src_overviews=True. The COG driver doesn't support either, so they only logged a warning on every write.

Not changed: raising on every GDAL warning

The #74 review suggested making write_cog raise whenever GDAL logs CPLE_NotSupported. That doesn't work cleanly. GDAL also logs '64' is an unexpected value for BLOCKSIZE creation option that should be >= 128 for every fixture with 64×64 tiles, even though it writes those tiles. A blanket check would need exceptions keyed on message text.

Instead, test_no_ignored_creation_options asserts that a plain write_cog call logs no warnings, which would have caught the two dead options. I also ran every generator with rasterio's log captured. With this change, the BLOCKSIZE warning is the only one left.

Tests

tests/test_write_cog.py calls write_cog directly into tmp_path and checks:

• predictor 2 with each supported codec, and predictor 3 on float data
• ValueError for JPEG, LERC, LZMA, PACKBITS and WEBP
• nodata, scale and offset
• no logged warnings

9 of its 16 cases fail on main. To let tests import the generators, pyproject.toml gains pythonpath = ["."]. #73 adds the identical lines, so that part merges cleanly.

No fixture changes: pixi run check regenerates every fixture byte for byte. pixi run test passes.

Merging with #73

#73 adds rewrite_big_endian directly below the copy(...) call this PR edits, so whichever lands second will likely get a one-line conflict.

🤖 Written by Claude Code

[kylebarron]

lgtm

[kylebarron]

is this automatic in the cog_profile?

[kylebarron]

Note

This reply was written by Claude (Claude Code), not by @kylebarron.

Yes. The COG driver always tiles: it writes the file with TILED=YES and takes the tile size from BLOCKSIZE (cogdriver.cpp#L1204-L1208). TILED isn't one of its own creation options, so passing it only logged driver COG does not support creation option TILED.

The same lines set COPY_SRC_OVERVIEWS=YES, so dropping copy_src_overviews=True is a no-op too. Without either option, pixi run check still regenerates every fixture byte for byte.

🤖 Written by Claude Code