On Tue, May 16, 2017 at 09:41:24AM -0700, Jonathan Nieder wrote: > Jeff King wrote: > > On Mon, May 15, 2017 at 11:25:03PM -0400, Jeff King wrote: > > >> One hack would be to look for BASH_FUNC_* in the environment and disable > >> the optimization in that case. I think that would make your case Just > >> Work. It doesn't help other oddball cases, like: > >> > >> - you're trying to run a shell builtin that behaves differently than > >> its exec-able counterpart > >> > >> - your shell has some other mechanism for defining commands that we > >> would not find via exec. I don't know of one offhand. Obviously $ENV > >> could point to a file which defines some, but for most shells would > >> not read any startup files for a non-interactive "sh -c" invocation. > > > > So I was thinking something like the patch below, though I guess > > technically you could look for BASH_FUNC_$argv[0]%%, which seems to be > > bash's magic variable name. I hate to get too intimate with those > > details, though. > > > > Another option is to speculatively run "foo" without the shell, and if > > execve fails to find it, then fall back to running the shell. That would > > catch any number of cases where the shell "somehow" finds a command that > > we can't. > > Hm. execvp explicitly does this when it hits ENOEXEC, but not for > ENOENT. Do you know why that is? When execvp(foo) falls back on ENOEXEC, it is not running "sh -c foo". It is actually running "sh foo" to run the script contents. So it's about letting you do: echo "no shebang line" >script chmod +x script ./script And nothing to do with shell builtins. > I think we want to behave consistently for shell builtins and for > exported functions --- they are different sides of the same problem, > and behaving differently between the two feels confusing. Yes, I think ideally we'd handle it all transparently. Although I'd also point out that Git the behavior under discussion dates back to 2009 and this is (as far as I can recall) the first report. So documenting the current behavior might not be that bad an option. -Peff