The cover fetch reused maxBodyBytes, the 4 MiB ceiling sized for series
pages, so any cover above it was rejected, logged, and retried forever
while the Series kept a monogram. Measured against asurascans on
2026-08-17 that is not an edge case: p90 is 4.52 MB and 3 of 25 covers
exceed 4 MiB, two of them plain JPEGs rather than the 8.57 MB animated
GIF the issue names.
Covers now have maxCoverBytes = 10 MiB, separate from the page cap: a
cover is one bounded binary asset, the page cap still has 3.5x headroom
over measured pages and should not be loosened along with it. 10 MiB is
~18% over the largest cover observed and matches the GitHub and Discord
image limits. The format offers no help in picking the number — GIF has
no maximum size at all — so docs/research/gif-maximum-byte-size.md
records the spec reading, the decoder behaviour, and the live
distribution the cap is derived from.
Transcoding was rejected: decoding is the OOM path, since Go's
image/gif allocates width x height per frame with no dimension guard
and a legal 65535^2 GIF would ask for ~4.29 GB on a 1974 MiB swapless
host.
sulthan
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