Tracking issue for `report-time`

[popzxc]

Tracks stabilization for the report-time and ensure-test-time libtest options.

[smoelius]

I propose that the methods for enabling and configuring this option be changed.

The option currently uses optflagopt, which means that one must use = to specify its parameter, e.g., --report-time=colored. If one doesn't use =, then the would-be parameter is interpreted as a filter, which is confusing. The difference is further jarring because no other libtest option uses optflagopt. Finally, the current implementation of --report-time does not produce an error when its parameter is not plain or colored.

I propose:

• the option be split into two options: --report-time, to enable the option, and --report-time-color, to configure the option
• the latter use optopt not optflagopt, so that use of = is optional when specifying the parameter
• the valid parameters to --report-time-color be always, never, and (if feasible) auto (the default) (These choices seem more conventional than plain and colored.)
• --report-time-color produce an error if its parameter is not among the three valid choices

Do others have opinions?

[matklad]

Note that cargo stabilized --timings option. I think it'll be best if we name libtest option the same, i.e., rename --report-time to --timings.