On Fri, Oct 18, 2019 at 10:37 AM SZEDER Gábor <szeder.dev@xxxxxxxxx> wrote: > On Thu, Oct 17, 2019 at 01:52:27PM -0400, Eric Sunshine wrote: > > > + case "$1" in > > > + --show-idx) show_idx=y ;; > > > + *) return 1 ;; > > > > Should this emit an error message to aid a person debugging a test > > which fails on a call to __git_find_on_cmdline()? [...] > > And printing anything to standard error during completion is > inherently bad: it disrupts the command line, can't be deleted [...] > Remaining silent about the unrecognized option > is in my opinion better, because then the completion script usually > does nothing, and Bash falls back to filename completion. Yeah, > that's not ideal, but at least the user can easily correct it and > finish entering the command. I had tunnel-vision and was thinking about this only in the context of the tests. However, while I agree that spewing errors during completion is not ideal, aren't there two different classes of errors to consider? Some errors can crop up via normal usage of Git commands in Real World situations; those errors should be suppressed since they are expected and can be tolerated. However, the second class of error (such as passing a bogus option to this internal function) is an outright programming mistake by a maintainer of the completion script itself, and it would be helpful to let the programmer know as early as possible about the mistake. Or, are there backward-compatibility or other concerns which would make emitting error messages undesirable even for outright programmer mistakes?