x/build: builder getting http 500 responses

[kardianos]

The windows-kardianos builder is sometimes getting 500 server errors. I think it started on June 18th.

2015/06/20 22:34:31 bad http response: 500 Internal Server Error
2015/06/20 22:48:18 bad http response: 500 Internal Server Error
2015/06/20 23:20:11 bad http response: 500 Internal Server Error
2015/06/21 00:00:18 bad http response: 500 Internal Server Error
2015/06/21 00:16:18 Canceled: Deadline exceeded (timeout)
2015/06/21 00:38:45 bad http response: 500 Internal Server Error
2015/06/21 01:18:38 bad http response: 500 Internal Server Error
2015/06/21 01:20:19 bad http response: 500 Internal Server Error
2015/06/21 02:43:24 bad http response: 500 Internal Server Error
2015/06/21 02:44:39 bad http response: 500 Internal Server Error
2015/06/21 03:40:03 bad http response: 500 Internal Server Error
2015/06/21 04:27:37 bad http response: 500 Internal Server Error
2015/06/21 05:00:33 bad http response: 500 Internal Server Error
2015/06/21 05:02:06 bad http response: 500 Internal Server Error
2015/06/21 05:42:40 bad http response: 500 Internal Server Error
2015/06/21 05:57:50 bad http response: 500 Internal Server Error
2015/06/21 06:22:52 bad http response: 500 Internal Server Error
2015/06/21 06:44:53 bad http response: 500 Internal Server Error

[kardianos]

Also I had to restart a session, killing builder abruptly. It looks like commit 3cab476 isn't getting sent down. Probably in limbo somewhere on the backend.

[bradfitz]

/cc @adg for build.golang.org issues

[adg]

This should be fixed now. Please re-open if you see it again.