patchpathspec: give better message for submodule related pathspec error

> diff --git a/pathspec.c b/pathspec.c
> index 22ca74a126..d522f43331 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"),
> +		       ce->name);

> 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;
>  }

> 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>
> ---
> 
> If you were following the mailing list closely today, you may sense
> that I am cleaning up stalled branches. :)
> 
> I think such a hot fix is warranted given how often we had reports
> on the mailing list.
> 
> Thanks,
> Stefan
> 
>  pathspec.c | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/pathspec.c b/pathspec.c
> index 22ca74a126..d522f43331 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"),
> +		       ce->name);
>  	return magic;