Re: [PATCH v3 6/8] dir: avoid unnecessary traversal into ignored directory

From: Junio C Hamano <gitster@pobox.com>
Date: May 10, 2021, 05:48 UTC
Message-ID: <xmqq35uvrvfv.fsf@gitster.g>
In-Reply-To: <66ffc7f02d08f3f07cb3cb2605b113a630f1e127.1620503945.git.gitgitgadget@gmail.com>

"Elijah Newren via GitGitGadget" <gitgitgadget@gmail.com> writes:

> Some sidenotes about possible confusion with dir.c:

Thanks for working on untangling this mess ;-)

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> * "ignored" often refers to an untracked ignore", i.e. a file which is
>   not tracked which matches one of the ignore/exclusion rules.  But you
>   can also have a "tracked ignore", a tracked file that happens to match
>   one of the ignore/exclusion rules and which dir.c has to worry about
>   since "git ls-files -c -i" is supposed to list them.

OK. This is to find a pattern in .gitignore that is too broad (i.e. if the path were to be added as a new thing today, it would require "add -f"), right? The combination of "-i -c" does make sense for that purpose.

> * The dir code often uses "ignored" and "excluded" interchangeably,
>   which you need to keep in mind while reading the code.

True. In tree .gitignore files are to hold exclude patterns, and per repository personal exclude file is called $GIT_DIR/info/exclude which is confusing.

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> Sadly, though,
>   it can get very confusing since ignore rules can have exclusions, as
>   in the last of the following .gitignore rules:
>       .gitignore
>       *~
>       *.log
>       !settings.log
>   In the last entry above, (pathspec->items[3].magic & PATHSPEC_EXCLUDE)
>   will be true due the the '!' negating the rule.  Someone might refer
>   to this as "excluded".

That one I've never heard of. As far as I am concerned, that is a negative exclude pattern.

I do wish we started the project with .gitignore files and $GIT_DIR/info/ignore both of which holds ignore patterns and negative ignore patterns from day one, but the boat sailed long time ago.