bug: body stream leak in compression methods when response is discarded

[pageton]

Description

In compress.go, brotli.go, and zstd.go, when a response has a body stream and the caller requests compression, the original body stream is wrapped in a NewStreamReader. The compression methods (brotliBody, gzipBody, deflateBody, zstdBody in http.go:1886-2072) only handle io.Closer/ReadCloserWithError on the wrapper, but if the response is discarded before reading, the inner stream is never closed.

// http.go:1886 (brotliBody example)
bs := resp.bodyStream
resp.bodyStream = NewStreamReader(func(w *bufio.Writer) {
    // bs is used inside callback, but if callback is never called...
    br := acquireBrotliReader(bs)
    // ...
})

This is particularly problematic for file-based body streams (e.g., from SendFile).

Impact

• File handle leaks when compressed responses are discarded without reading
• Connection leaks for network-based body streams

Suggested Fix

Ensure Response.Reset() and closeBodyStream() properly cascade Close to inner streams even when the outer stream wrapper was never read.

File

http.go:1886-1901, http.go:1944-1959, http.go:2002-2017, http.go:2057-2072