MANIFEST download failing after failed run

[mattl]

2018-03-13 21:11:06,966 DEBUG ./wpt:stderr INFO:manifest:Skipping manifest download because existing file is recent
2018-03-13 21:11:06,966 DEBUG ./wpt:stderr Traceback (most recent call last):
2018-03-13 21:11:06,966 DEBUG ./wpt:stderr File "./wpt", line 5, in
2018-03-13 21:11:06,966 DEBUG ./wpt:stderr wpt.main()
2018-03-13 21:11:06,966 DEBUG ./wpt:stderr File "/home/wptrunner/web-platform-tests/tools/wpt/wpt.py", line 132, in main
2018-03-13 21:11:06,966 DEBUG ./wpt:stderr rv = script(*args, **kwargs)
2018-03-13 21:11:06,967 DEBUG ./wpt:stderr File "/home/wptrunner/web-platform-tests/tools/manifest/update.py", line 96, in run
2018-03-13 21:11:06,967 DEBUG ./wpt:stderr update_from_cli(**kwargs)
2018-03-13 21:11:06,967 DEBUG ./wpt:stderr File "/home/wptrunner/web-platform-tests/tools/manifest/update.py", line 41, in update_from_cli
2018-03-13 21:11:06,967 DEBUG ./wpt:stderr m = manifest.load(tests_root, path)
2018-03-13 21:11:06,967 DEBUG ./wpt:stderr File "/home/wptrunner/web-platform-tests/tools/manifest/manifest.py", line 225, in load
2018-03-13 21:11:06,968 DEBUG ./wpt:stderr rv = Manifest.from_json(tests_root, json.load(f))
2018-03-13 21:11:06,968 DEBUG ./wpt:stderr File "/usr/lib/python2.7/json/init.py", line 291, in load
2018-03-13 21:11:06,969 DEBUG ./wpt:stderr **kw)
2018-03-13 21:11:06,969 DEBUG ./wpt:stderr File "/usr/lib/python2.7/json/init.py", line 339, in loads
2018-03-13 21:11:06,969 DEBUG ./wpt:stderr return _default_decoder.decode(s)
2018-03-13 21:11:06,969 DEBUG ./wpt:stderr File "/usr/lib/python2.7/json/decoder.py", line 364, in decode
2018-03-13 21:11:06,971 DEBUG ./wpt:stderr obj, end = self.raw_decode(s, idx=_w(s, 0).end())
2018-03-13 21:11:06,971 DEBUG ./wpt:stderr File "/usr/lib/python2.7/json/decoder.py", line 382, in raw_decode
2018-03-13 21:11:06,971 DEBUG ./wpt:stderr raise ValueError("No JSON object could be decoded")
2018-03-13 21:11:06,971 DEBUG ./wpt:stderr ValueError: No JSON object could be decoded
Traceback (most recent call last):
File "./run/run.py", line 599, in
main(args.platform_id, platform, args, config)
File "./run/run.py", line 105, in main
setup_wpt(config, logger)
File "./run/run.py", line 375, in setup_wpt
'%d from command %s' % (proc.returncode, command))
AssertionError: Got non-0 return code: 1 from command ['./wpt', 'manifest', '--work']

I removed it manually.

[jugglinmike]

We addressed this issue via the introduction of a Buildbot-driven infrastructure (see gh-522).