Re: [PATCH] pathspec: give better message for submodule related pathspec error

[Junio C Hamano <gitster@pobox.com>]

Stefan Beller <sbeller@google.com> writes:

> Every once in a while someone complains to the mailing list to have
> run into this weird assertion[1].
>
> The usual response from the mailing list is link to old discussions[2],
> and acknowledging the problem stating it is known.
>
> For now just improve the user visible error message.

Thans. judging from the date: header I take this is meant as v3 that
supersedes v2 done on Wednesday.

It is not clear in the above that what this thing is.  Given that we
are de-asserting it, is the early part of the new code diagnosing an
end-user error (i.e. you gave me a pathspec but that extends into a
submodule which is a no-no)?  The "was a submodule issue" comment
added is "this is an end-user mistake, there is nothing to fix in
the code"?

I take that the new "BUG" thing tells the Git developers that no
sane codepath should throw an pathspec_item that satisfies the
condition of the if() statement for non-submodules?

> diff --git a/pathspec.c b/pathspec.c
> index 22ca74a126..b446d79615 100644
> --- a/pathspec.c
> +++ b/pathspec.c
> @@ -313,8 +313,23 @@ static unsigned prefix_pathspec(struct pathspec_item *item,
>  	}
>  
>  	/* sanity checks, pathspec matchers assume these are sane */
> -	assert(item->nowildcard_len <= item->len &&
> -	       item->prefix         <= item->len);
> +	if (item->nowildcard_len > item->len ||
> +	    item->prefix         > item->len) {
> +		/* Historically this always was a submodule issue */
> +		for (i = 0; i < active_nr; i++) {
> +			struct cache_entry *ce = active_cache[i];
> +			int ce_len = ce_namelen(ce);
> +			int len = ce_len < item->len ? ce_len : item->len;
> +			if (!S_ISGITLINK(ce->ce_mode))
> +				continue;

Computation of ce_len and len are better done after this check, no?

> +			if (!memcmp(ce->name, item->match, len))
> +				die (_("Pathspec '%s' is in submodule '%.*s'"),
> +					item->original, ce_len, ce->name);
> +		}
> +		/* The error is a new unknown bug */
> +		die ("BUG: item->nowildcard_len > item->len || item->prefix > item->len)");
> +	}
> +
>  	return magic;
>  }
>  
> diff --git a/t/t6134-pathspec-in-submodule.sh b/t/t6134-pathspec-in-submodule.sh
> new file mode 100755
> index 0000000000..e62dbb7327
> --- /dev/null
> +++ b/t/t6134-pathspec-in-submodule.sh
> @@ -0,0 +1,33 @@
> +#!/bin/sh
> +
> +test_description='test case exclude pathspec'
> +
> +. ./test-lib.sh
> +
> +test_expect_success 'setup a submodule' '
> +	test_commit 1 &&
> +	git submodule add ./ sub &&

Is this adding our own project as its submodule?  

It MIGHT be a handy hack when writing a test, but let's stop doing
that insanity.  No sane project does that in real life, doesn't it?

Create a subdirectory, make it a repository, have a commit there and
bind that as our own submodule.  That would be a more normal way to
start your own superproject and its submodule pair if they originate
together at the same place.

Better yet create a separate repository, have a commit there, and
then pull it in with "git submodule add && git submodule init" into
our repository.  That would be the normal way to borrow somebody
else's project as a part of your own superproject.

> +	git commit -a -m "add submodule" &&
> +	git submodule deinit --all
> +'
> +
> +cat <<EOF >expect
> +fatal: Pathspec 'sub/a' is in submodule 'sub'
> +EOF
> +
> +test_expect_success 'error message for path inside submodule' '
> +	echo a >sub/a &&
> +	test_must_fail git add sub/a 2>actual &&
> +	test_cmp expect actual
> +'
> +
> +cat <<EOF >expect
> +fatal: Pathspec '.' is in submodule 'sub'
> +EOF
> +
> +test_expect_success 'error message for path inside submodule from within submodule' '
> +	test_must_fail git -C sub add . 2>actual &&
> +	test_cmp expect actual
> +'
> +
> +test_done