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id: f06329e9-7e81-41f8-acf2-a48baf70cdcd title: 'build aborts (allocator) on large blobs: every file is read fully into memory' state: closed labels:

• robustness assignees: [] milestone: null created: 2026-10-27T14:54:10.641778270Z updated: 2026-10-27T15:41:26.855301643Z

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build reads every blob fully into memory (gitx::show → run_git → Vec<u8>), regardless of size. PREVIEW_MAX_BYTES (256 KiB) only decides whether the page renders a preview — the bytes were already in RAM.

Verified:

$ head -c 400000000 /dev/zero > big.bin && git add -A && git commit -m big
$ ( ulimit -v 900000; hu13 build . -o out )
memory allocation of 400000000 bytes failed
Aborted (core dumped)          # exit 134

The failure is a raw allocator abort (SIGABRT), not a clean hu13: ... error, and in entrypoint.sh this means the container crash-loops before serve starts.

Real repos carry large binaries (videos, datasets, vendored archives) and a PR can add one deliberately. There is no --max-blob and no streaming path.

Fix direction:

• git cat-file --batch with a size probe (git cat-file -s <rev>:<path> first) so blobs above a threshold are never read; write a placeholder page and skip/stream the raw/ copy
• or stream git show straight into the raw/ file and only keep the first 256 KiB for preview/binary sniff
• make the threshold configurable (--max-blob, HU13_MAX_BLOB) with a documented default (say 10 MiB) and a clear warning line when a file is skipped
• ensure the failure mode is a clean error, not an allocator abort

Acceptance:

• a repo with a 500 MB blob builds (skips it, warns) instead of aborting
• peak RSS stays bounded by the threshold, not by the largest blob
• raw/ either contains the full file (streamed) or is documented as skipped