Re: [PATCH 18/30] subtree: use $* instead of $@ as appropriate

From: Luke Shumaker <lukeshu@lukeshu.com>
Date: Apr 23, 2021, 23:50 UTC
Message-ID: <87zgxoa7cj.wl-lukeshu@lukeshu.com>
In-Reply-To: <CAPig+cTb-h=Qb9asvh+MVH2s5uj7szP_QOPpcm1bqdE6DK9V7g@mail.gmail.com>

On Fri, 23 Apr 2021 14:40:31 -0600, Eric Sunshine wrote:

Show 19 quoted lines

> 
> On Fri, Apr 23, 2021 at 3:43 PM Luke Shumaker <lukeshu@lukeshu.com> wrote:
> > $* is for when you want to smash things together, whitespace-separated;
> > $@ is for when you want them to be separate strings.  There are a couple
> > of places in subtree that erroneously use $@ when smashing args together
> > in to an error message.
> 
> Can we be explicit and say "$@" in the commit message rather than bare
> $@ since the unquoted form is not magical and acts exactly like $*.
> 
> Also: s/in to/into/
> 
> Nit: I have some trouble following what the commit message is actually
> trying to say with "smash things" and "separate strings". It might be
> simpler to say merely that use of "$@" in these particular instances
> is overkill and possibly misleading to readers not familiar with the
> finer details of $* vs. "$@".
> 
> The patch itself makes sense.

How's this:

--- subtree: use "$*" instead of "$@" as appropriate

"$*" is for when you want to concatenate the args together, whitespace-separated; and "$@" is for when you want them to be separate strings.

There are several places in subtree that erroneously use $@ when concatenating args together into an error message.

For instance, if the args are argv[1]="dead" and argv[2]="beef", then the line

    die "You must provide exactly one revision.  Got: '$@'"

surely intends to call 'die' with the argument

    argv[1]="You must provide exactly one revision.  Got: 'dead beef'"

however, because the line used $@ instead of $*, it will actually call 'die' with the arguments

    argv[1]="You must provide exactly one revision.  Got: 'dead"
    argv[2]="beef'"

This isn't a big deal, because 'die' concatenates its arguments together anyway (using "$*"). But that doesn't change the fact that it was a mistake to use $@ instead of $*, even though in the end $@ still ended up doing the right thing. ---

-- 
Happy hacking,
~ Luke Shumaker