Greptile Summary

This PR adds transparent auto-decompression of inbound request bodies for gzip/x-gzip, deflate, and zstd Content-Encoding values, stripping the encoding headers after decoding so upstream LLM providers receive a plain JSON body. The deflate path correctly attempts zlib-wrapped decoding first and falls back to raw DEFLATE when the header check fails, addressing a known RFC ambiguity.

• Decompression logic (llm/httpclient/utils.go): new decodeRequestBody switch and decodeZlibOrFlate helper; the zlib\u2192raw DEFLATE fallback only fires when zlib.NewReader rejects the header, leaving a gap where raw DEFLATE streams whose first two bytes accidentally satisfy the zlib checksum are mis-detected as zlib and then fail to decode.
• Tests (llm/httpclient/utils_test.go): thorough coverage of all three encodings, identity, empty body, error cases, and case-insensitive header handling; no test for the edge-case raw DEFLATE / coincidental zlib header collision.
• Dependencies: adds github.com/klauspost/compress v1.18.0 for zstd support; lock files updated across go.mod/go.sum and frontend pnpm-lock.yaml (frontend lock change appears to be an unrelated dependency cleanup).

Confidence Score: 4/5

Safe to merge with the zlib fallback gap fixed; the bug only manifests for raw DEFLATE bodies whose first two bytes coincidentally satisfy the zlib checksum, but when it does trigger the request silently fails.

The decompression logic is correct for the vast majority of real-world inputs, but decodeZlibOrFlate stops at the first io.ReadAll error after a successful zlib.NewReader call without retrying as raw DEFLATE. A raw DEFLATE stream with a coincidental zlib-like header will be rejected rather than decoded successfully.

llm/httpclient/utils.go — specifically decodeZlibOrFlate

Important Files Changed

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart TD
    A[Incoming HTTP Request] --> B[io.ReadAll body]
    B --> C{len body > 0?}
    C -- No --> G[req.Body = nil]
    C -- Yes --> D{Content-Encoding header?}
    D -- None / identity --> E[return body as-is]
    D -- gzip / x-gzip --> F1[gzip.NewReader]
    F1 -- error --> ERR[return error]
    F1 -- ok --> F2[io.ReadAll]
    F2 -- error --> ERR
    F2 -- ok --> HDR1[Del Content-Encoding Del Content-Length]
    HDR1 --> G
    D -- deflate --> Z1[zlib.NewReader]
    Z1 -- error --> Z2[flate.NewReader io.ReadAll]
    Z1 -- ok --> Z3[io.ReadAll]
    Z3 -- error --> ERR2[return error no fallback to flate]
    Z3 -- ok --> HDR2[Del Content-Encoding Del Content-Length]
    Z2 -- error --> ERR
    Z2 -- ok --> HDR2
    HDR2 --> G
    D -- zstd --> S1[zstd decoder.DecodeAll]
    S1 -- error --> ERR
    S1 -- ok --> HDR3[Del Content-Encoding Del Content-Length]
    HDR3 --> G
    D -- other --> ERR3[unsupported content encoding error]
    G --> H[Return Request]

_{Reviews (2): Last reviewed commit: "feat: auto decompress request body, clos..." | Re-trigger Greptile}