From: Junio C Hamano <gitster@pobox.com>
To: Brandon Williams <bmwill@google.com>
Cc: git@vger.kernel.org, "Heiko Voigt" <hvoigt@hvoigt.net>,
"Nguyễn Thái Ngọc Duy" <pclouds@gmail.com>,
"Stefan Beller" <sbeller@google.com>
Subject: Re: [PATCH] ls-files: add pathspec matching for submodules
Date: Mon, 19 Sep 2016 11:04:04 -0700 [thread overview]
Message-ID: <xmqq1t0fg417.fsf@gitster.mtv.corp.google.com> (raw)
In-Reply-To: <CAKoko1r_WATxJzxQrQW2VBkhuKquv=yQv6sB_eCMgH6qavS__Q@mail.gmail.com> (Brandon Williams's message of "Mon, 19 Sep 2016 10:26:27 -0700")
Brandon Williams <bmwill@google.com> writes:
>> Again, what do we have in "name" and "item" at this point? If we
>> have a submodule at "sub/" and we are checking a pathspec element
>> "sub/dir1/*", what is the non-wildcard part of the pathspec and what
>> is the "string"? Aren't they "sub/dir1/" and "sub/" respectively,
>> which would not pass ps_strncmp() and produce a (false) negative?
>
> item will be the pathspec_item struct that we are trying to match against.
... which would mean "sub/dir1/" in the above example (which is
followed by '*' that is wildcard).
> name will be the file we are trying to match, which should already have the
> 'prefix' cut off (this is the prefix that is used as an optimization
> in the common
> case, which isn't used in the submodule case).
... which would be "sub/" in the above example, because we disable
the common-prefix optimization.
So in short, the answer to the last questions in the first quoted
paragraph are yes, yes, and "no they do not pass ps_strncmp()"?
>> I am starting to have a feeling that the best we can do in this
>> function safely is to see if prefix (i.e. the constant part of the
>> pathspec before the first wildcard) is long enough to cover the
>> "name" and if "name" part [matches or does not match] ...
>> If these two checks cannot decide, we may have to be pessimistic and
>> say "it may match; we don't know until we descend into it".
>> ...
>> So I would think we'd be in the business of counting slashes in the
>> name (called "string" in this function) and the pathspec, while
>> noticing '*' and '**' in the latter, and we may be able to be more
>> precise, but I am not sure how complex the end result would become.
>
> I agree, I'm not too sure how much more complex the logic would need
> to be to handle
> all matters of wildcard characters. We could initially be more
> lenient on what qualifies as
> a match and then later (or in the near future) revisit the wildmatch
> function (which is complex)
> and see if we can add better matching capabilities more suited for
> submodules while at the
> same time fixing that bug discussed above.
I think it is reasonable to start a function that is meant to never
have false negatives pessimistic and return "might match" from it
when in doubt.
Thanks.
next prev parent reply other threads:[~2016-09-19 18:04 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-14 23:57 [RFC] extending pathspec support to submodules Brandon Williams
2016-09-15 11:57 ` Heiko Voigt
2016-09-15 15:26 ` Brandon Williams
2016-09-15 22:08 ` Junio C Hamano
2016-09-15 22:28 ` Stefan Beller
2016-09-16 9:34 ` Heiko Voigt
2016-09-16 18:40 ` Brandon Williams
2016-09-17 0:59 ` [PATCH] ls-files: add pathspec matching for submodules Brandon Williams
2016-09-17 3:46 ` Junio C Hamano
2016-09-18 18:40 ` Brandon Williams
2016-09-19 17:00 ` Junio C Hamano
2016-09-19 17:26 ` Brandon Williams
2016-09-19 18:04 ` Junio C Hamano [this message]
2016-09-19 18:20 ` Brandon Williams
2016-09-19 18:22 ` Junio C Hamano
2016-09-19 18:30 ` Brandon Williams
2016-09-19 18:34 ` Junio C Hamano
2016-09-19 18:35 ` Brandon Williams
2016-09-19 18:52 ` [PATCH v2] " Brandon Williams
2016-09-19 23:21 ` Junio C Hamano
2016-09-20 16:30 ` Brandon Williams
2016-09-20 21:03 ` Brandon Williams
2016-09-21 17:12 ` Junio C Hamano
2016-09-21 17:49 ` Junio C Hamano
2016-09-19 18:18 ` [PATCH] " Junio C Hamano
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