url: support suppressing Accept header Sending this header automatically could interfere with future testing and client behavior. Let's add a knob to disable the behavior. We don't have a control for User-Agent because urllib will send it if we don't set something. I don't feel like hacking into the bowels of urllib to figure out how to suppress that. UA shouldn't be used for anything meaningful. So it shouldn't pose any problems beyond non-determinism (since the header has the Mercurial version in it). Differential Revision: https://phab.mercurial-scm.org/D2843

util: don't log low-level I/O calls for HTTP peer `hg debugwireproto` is useful for testing HTTP interactions. Possibly more useful than `get-with-headers.py`. But one thing that makes it annoying for mid-level tests is that it logs all API calls, such as readline(). This makes output - especially headers - overly verbose. This commit teaches our file and socket observers to not log API calls on functions dealing with data. We change the behavior of `hg debugwireproto` to enable this mode by default. --debug can be added to restore the previous behavior. As the test changes demonstrate, this makes tests much easier to read. As a bonus, it also removes some required (glob) over lengths in system call results. One thing that's lacking is knowing which side sent data. But we can fix this in a follow-up once it becomes a problem. Differential Revision: https://phab.mercurial-scm.org/D2842