net::ERR_CONTENT_LENGTH_MISMATCH about gziphandler

[tamasd]

I have a test case that started failing in the last few days. There is a similar one that succeeds. The one that fails serves an html file (with http.ServeFile()), and the one that succeeds serves a binary file the same way. The code is exactly the same, only the file name is different.

In case of the html file, the headers are:

HTTP/1.1 200 OK
Accept-Ranges: bytes
Content-Type: text/html; charset=utf-8
Date: Sun, 18 Sep 2016 17:52:39 GMT
Last-Modified: Sun, 14 Jun 2015 14:24:51 GMT
Set-Cookie: _SESSION=; Path=/; Expires=Mon, 18 Sep 2017 17:52:39 GMT; HttpOnly
Vary: Accept-Encoding

But in case of the binary file, the headers are different:

HTTP/1.1 200 OK
Transfer-Encoding: chunked
Content-Type: application/octet-stream
Date: Sun, 18 Sep 2016 17:52:39 GMT
Set-Cookie: _SESSION=; Path=/; Expires=Mon, 18 Sep 2017 17:52:39 GMT; HttpOnly
Vary: Accept-Encoding

I use http.Client in both cases to retrive the results. In the failing case, ioutil.ReadAll() returns an io.ErrUnexpectedEOF error, but the returned data matches exactly the data on the disk. If I disable the gzip encoding in the failing case, by sending Accept-Encoding: identity, the test succeeds. In both cases, the response's Uncompressed field is true.

[tamasd]

I did a bisect. My tests are green with 44afc59. The next commit d3d7d67 makes a lot of my tests fail, and then at cdd181b I can reproduce the exact same failure.

[wayneashleyberry]

Thanks for the fix @jprobinson 🎉