On Mon, Jan 25, 2021 at 9:42 AM Derrick Stolee via GitGitGadget
<gitgitgadget@xxxxxxxxx> wrote:
>
> From: Derrick Stolee <dstolee@xxxxxxxxxxxxx>
>
> When we have sparse directory entries in the index, we want to compare
> that directory against sparse-checkout patterns. Those pattern matching
> algorithms are built expecting a file path, not a directory path. This
> is especially important in the "cone mode" patterns which will match
> files that exist within the "parent directories" as well as the
> recursive directory matches.
>
> If path_matches_pattern_list() is given a directory, we can add a bogus
> filename ("-") to the directory and get the same results as before,
> assuming we are in cone mode. Since sparse index requires cone mode
> patterns, this is an acceptable assumption.
Why is "-" a bogus filename? Is that only on certain operating
systems, or are you just not expecting a user to name their file with
such a bad name? What if there is a file with that name in that
directory in the repository; do you need the pathname to be bogus?
What do you mean by "get the same results as before"? The first
paragraph suggests the code wouldn't handle a directory path, and that
not handling it was problematic, so it seems unlikely you want the
same results as that. But it's not clear what the "before" refers to
here.
> Signed-off-by: Derrick Stolee <dstolee@xxxxxxxxxxxxx>
> ---
> dir.c | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/dir.c b/dir.c
> index ad6eb033cb1..c786fa98d0e 100644
> --- a/dir.c
> +++ b/dir.c
> @@ -1384,6 +1384,11 @@ enum pattern_match_result path_matches_pattern_list(
> strbuf_addch(&parent_pathname, '/');
> strbuf_add(&parent_pathname, pathname, pathlen);
>
> + /* Directory requests should be added as if they are a file */
> + if (parent_pathname.len > 1 &&
> + parent_pathname.buf[parent_pathname.len - 1] == '/')
Ah, this looks like a case where the trailing slash is helpful;
without it, you might have to feed extra data in through the call
hierarchy to signify that this is a directory entry.
> + strbuf_add(&parent_pathname, "-", 1);
> +
> if (hashmap_contains_path(&pl->recursive_hashmap,
> &parent_pathname)) {
> result = MATCHED_RECURSIVE;
hashmap_contains_path? Don't we already know (modulo special cases of
our bogus value not quite being bogus enough) that this is false since
we were adding a bogus path? How could the hashmap have a bogus value
in it? Won't this particular call fail with or without our adding "-"
to the end of the path?
After this hashmap_contains_path() call, the subsequent code looks for
the parent of the path by stripping off everything after the last
'/'...which seems like the relevant code anyway. Is the problem that
the hashmap_contains_path() call was returning true when we didn't add
"-" to the end? If so, can we use and if or a goto instead to make
the code skip this first check and move on to where we want it to go?
Or am I misunderstanding something about this code?
