direnv exec: impossible command line

[Profpatsch]

exec [DIR] COMMAND [...ARGS]:

Means that both DIR and an unspecified amount of ARGS are optional.
It should be impossible for direnv to figure out whether the second argument is a DIR or COMMAND.

And indeed:

> direnv exec echo a b c
direnv: error stat echo: no such file or directory
> direnv exec $PWD echo a b c
direnv: loading .envrc
a b c

• target shell: fish
• direnv version: 2.19.2
• OS release: NixOS 18.09

[zimbatm]

yes it's not great, the result of organic growth. But I don't want to break backward-compatibility now.

The best solution is to always pass the DIR and use . as the default.

[Profpatsch]

Since the behavior always requires DIR in practice, we can just mark it as non-optional in the docs.

[Profpatsch]

Oh wait … wait

direnv/cmd_exec.go

Lines 33 to 43 in e05d32a

	if fi.IsDir() {
	if len(args) < 3 {
	return fmt.Errorf("missing COMMAND argument")
	}
	command = args[2]
	args = args[2:]
	} else {
	command = rcPath
	rcPath = filepath.Dir(rcPath)
	args = args[1:]
	}

I didn’t expect this to be a thing.

[zimbatm]

yeah, it's bad...

[Profpatsch]

The “just a command” case is broken at the moment however:

> direnv exec bash
direnv: error stat bash: no such file or directory

I think that needs to be fixed nonetheless.

[zimbatm]

Ok, let's make the DIR mandatory then. It must have been broken for a long time and nobody complained.