1949311 - Improve `mach try perf` messages when ssh keys are not configured

Status: NEW

(Testing :: Performance, task, P2)

Description

[Ted Campbell [:tcampbell]]

With the move to Lando for submitting patches and try jobs in commands like mach try fuzzy, an authorized SSH key (and ~/.ssh/config file) are not needed for most firefox development. If you have a fresh dev environment and run mach try perf you will get a long error.

remote: [e-mail]: Permission denied (publickey).
fatal: called `Result::unwrap()` on an `Err` value: ParseIntError { kind: Empty }
Run the command again with `git -c cinnabar.check=traceback <command>` to see the full traceback.
Error running mach:

    mach try perf --single-run

The error occurred in code that was called by the mach command. This is either
a bug in the called code itself or in the way that mach is calling it.
You can invoke ``./mach busted`` to check if this issue is already on file. If it
isn't, please use ``./mach busted file try`` to report it. If ``./mach busted`` is
misbehaving, you can also inspect the dependencies of bug 1543241.

If filing a bug, please include the full output of mach, including this error
message.

The details of the failure are as follows:

subprocess.CalledProcessError: Command '('C:\\Program Files\\Git\\cmd\\git.EXE', '-c', 'cinnabar.data=never', 'push', 'hg::ssh://hg.mozilla.org/try', '+c6a547ea3eb3668f21ef659b28afa4e1e509db2e:refs/heads/branches/default/tip')' returned non-zero exit status 128.

  File "D:\mozilla-unified\tools\tryselect\mach_commands.py", line 530, in try_perf
    return run(command_context, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "D:\mozilla-unified\tools\tryselect\mach_commands.py", line 174, in run
    return mod.run(**kwargs)
           ^^^^^^^^^^^^^^^^^
  File "d:\mozilla-unified\tools\tryselect\selectors\perf.py", line 1584, in run
    PerfParser.run(
  File "d:\mozilla-unified\tools\tryselect\selectors\perf.py", line 1429, in run
    PerfParser.perf_push_to_try(
  File "d:\mozilla-unified\tools\tryselect\selectors\perf.py", line 1306, in perf_push_to_try
    push_to_try(
  File "d:\mozilla-unified\tools\tryselect\push.py", line 261, in push_to_try
    vcs.push_to_try(
  File "d:\mozilla-unified\python\mozversioncontrol\mozversioncontrol\repo\git.py", line 231, in push_to_try
    self._push_to_try_with_log_capture(
  File "d:\mozilla-unified\python\mozversioncontrol\mozversioncontrol\repo\base.py", line 290, in _push_to_try_with_log_capture
    raise subprocess.CalledProcessError(

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The key line is the first one which an experienced linux developer might recognize as indicated the problem. A better experience for first time users of mach try perf would be nice.

Likely we just need to get support of Lando.