On Tue, Jan 14, 2020 at 07:25:58PM +0000, Derrick Stolee via GitGitGadget wrote:
> From: Derrick Stolee <dstolee@xxxxxxxxxxxxx>
>
> When core.sparseCheckoutCone is enabled, the 'git sparse-checkout set'
> command creates a restricted set of possible patterns that are used
> by a custom algorithm to quickly match those patterns.
>
> If a user manually edits the sparse-checkout file, then they could
> create patterns that do not match these expectations. The cone-mode
> matching algorithm can return incorrect results. The solution is to
> detect these incorrect patterns, warn that we do not recognize them,
> and revert to the standard algorithm.
>
> Check each pattern for the "**" substring, and revert to the old
> logic if seen. While technically a "/<dir>/**" pattern matches
> the meaning of "/<dir>/", it is not one that would be written by
> the sparse-checkout builtin in cone mode. Attempting to accept that
> pattern change complicates the logic and instead we punt and do
> not accept any instance of "**".
That all makes sense.
> diff --git a/dir.c b/dir.c
> index 22d08e61c2..f8e350dda2 100644
> --- a/dir.c
> +++ b/dir.c
> @@ -651,6 +651,13 @@ static void add_pattern_to_hashsets(struct pattern_list *pl, struct path_pattern
> return;
> }
>
> + if (strstr(given->pattern, "**")) {
> + /* Not a cone pattern. */
> + pl->use_cone_patterns = 0;
> + warning(_("unrecognized pattern: '%s'"), given->pattern);
> + goto clear_hashmaps;
> + }
The clear_hashmaps label already unsets pl->use_cone_patterns, so the
first line is redundant (the same is true of existing goto jumps, as
well, though).
I wondered whether this warning could be triggered accidentally by
somebody who just happened to add such a pattern. But we'd exit
immediately from add_pattern_to_hashsets() immediately unless the user
has set core.sparseCheckoutCone. And if that's set, then warning is
definitely the right thing to do.
-Peff
