Re: [PATCH 7/8] sparse-checkout: properly match escaped characters

From: Derrick Stolee <stolee@gmail.com>
Date: Jan 14, 2020, 22:08 UTC
Message-ID: <79915215-15c1-7e38-6f06-294c719ff260@gmail.com>
In-Reply-To: <20200114212120.GC3949560@coredump.intra.peff.net>

On 1/14/2020 4:21 PM, Jeff King wrote:

Show 14 quoted lines

> On Tue, Jan 14, 2020 at 07:26:01PM +0000, Derrick Stolee via GitGitGadget wrote:
> 
>> From: Derrick Stolee <dstolee@microsoft.com>
>>
>> In cone mode, the sparse-checkout feature uses hashset containment
>> queries to match paths. Make this algorithm respect escaped asterisk
>> (*) and backslash (\) characters.
>>
>> Create dup_and_filter_pattern() method to convert a pattern by
>> removing escape characters and dropping an optional "/*" at the end.
>> This method is available in dir.h as we will use it in
>> builtin/sparse-chekcout.c in a later change.
> 
> s/chekcout/checkout/

Thanks.

> It took me a minute to understand the problem here, but I think it's: if
> a path in the sparse-checkout file has "\*" in it, we'd try to match a
> literal "\*" in the hash, not "*"?

Yes, the hashset would have the string "\*" instead of the string "*". This
would lead to missing directories when cone mode is enabled compared to
cone mode not being enabled.

> But we wouldn't run into that yet because we don't properly _write_ the
> escaped names until patch 8.

We wouldn't run into it when using the builtin, but also a user could edit their sparse-checkout file manually OR figure out how to get the "right" pattern by running "git sparse-checkout set "my\\*dir" (where the escaped backslash is collapsed by the shell and Git sees "my\*dir".

Thanks, -Stolee