/ curl Public
content_encoding: fix inflate_stream for no bytes available #2060
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Prior to this change libcurl's inflate_stream could call zlib's inflate
even when no bytes were available, causing inflate to return
Z_BUF_ERROR, and then inflate_stream would treat that as a hard error
and return CURLE_BAD_CONTENT_ENCODING.
According to the zlib FAQ, Z_BUF_ERROR is not fatal.
This bug would happen randomly since packet sizes are arbitrary. A test
of 10,000 transfers had 55 fail (ie 0.55%).
Bug first seen in CI:
success case example:
fail case example:
Z_BUF_ERROR (-5). inflate_stream treats it as a hard error, but according to the zlib FAQ it's not.
rather than deal with the error this change prevents it from occurring in the first place by returning when there are no bytes available