[PATCHv2] pathspec: give better message for submodule related pathspec error

[Stefan Beller <sbeller@google.com>]

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.

[1] https://www.google.com/search?q=item-%3Enowildcard_len
[2] http://git.661346.n2.nabble.com/assert-failed-in-submodule-edge-case-td7628687.html
    https://www.spinics.net/lists/git/msg249473.html

Signed-off-by: Stefan Beller <sbeller@google.com>
---

Peff wrote:
> Don't you need to flip the logic here? An assert() triggers when the
> condition is not true, but an "if" does the opposite. So "assert(X)"
> should always become "if (!X) die(...)".

Duh! and it should compile as well. 

Thanks,
Stefan

 pathspec.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/pathspec.c b/pathspec.c
index 22ca74a126..4724d522f2 100644
--- a/pathspec.c
+++ b/pathspec.c
@@ -313,8 +313,11 @@ 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)
+		die (_("Path leads inside submodule '%s', but the submodule "
+		       "was not recognized, i.e. not initialized or deleted"),
+		       item->original);
 	return magic;
 }
 
-- 
2.11.0.196.gee862f456e.dirty