syntax: regression in parsing of "declare"

[cyphar]

We just hit this in runc in the past few days. If you run shfmt on something like this:

export completion_func=_some_func_name
declare -F $completion_func

You get this error even though it is entirely valid bash.

2:12: "declare" must be followed by names or assignments

[mvdan]

Thanks! Will look into it.

[mvdan]

@cyphar just to confirm, you only use declare ... $var in the context where $var only holds a name like foo, correct? You wouldn't do it where var='foo[0]' or var='foo=bar', hopefully?

[cyphar]

declare -F $var is only valid if $var is a name. However, note that declare $var is valid if var="a=b". For example:

$ export var="a=b"
$ declare $var
$ echo $a
b

We're not using the latter, but you should be aware that is a valid bash-ism. declare k[0] is also valid.

[mvdan]

I ran the same tests - that's why I'm asking. I think I'll just allow this assuming that $var just contains a name no matter what, as otherwise this would be a rabbit hole.

[cyphar]

Thanks for the incredibly fast turnaround @mvdan. 😸