Description:
------------
In ext/zlib/zlib.c:static PHP_FUNCTION(ob_gzhandler)
the HTTP_ACCEPT_ENCODING is not parsed.

PHP only checks, if the string "gzip" oder "deflate" is inside the header and enables outputcompression if set.

RFC2616 allows for example that a probability (q) is set, which could be also 0 (disable compression) but PHP will enable it.

For example:
Accept-Encoding: gzip;q=0.0
   actual result: compressed output
   expected result: uncompressed output

Accept-Encoding: thisisnotavalidgzipacceptencoding
   actual result: compressed output
   expected result: uncompressed output

   

Test script:
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<?php

ini_set("zlib.output_compression", "1");
ob_start();
echo "foo";
ob_get_clean();