Subject: RE: [PATCH] pathspec: correct an empty string used as a pathspec element

From: <[email-masked]>
Date: Sun, 29 May 2022 19:01:11 -0400

On May 29, 2022 6:40 PM, Junio C Hamano wrote:
>Pathspecs with only negative elements did not work with some commands that
>pass the pathspec along to a subprocess.  For instance,
>
>    $ git add -p -- ':!*.txt'
>
>should add everything except for paths ending in ".txt", but it gets
complaint from
>underlying "diff-index" and aborts.
>
>We used to error out when a pathspec with only negative elements in it,
like the
>one in the above example.  Later, 859b7f1d (pathspec:
>don't error out on all-exclusionary pathspec patterns, 2017-02-07) updated
the
>logic to add an empty string as an extra element.  The intention was to let
the
>extra element to match everything and let the negative ones given by the
user to
>subtract from it.
>
>At around the same time, we were migrating from "an empty string is a valid
>pathspec element that matches everything" to "either a dot or ":/" is used
to
>match all, and an empty string is rejected", between d426430e (pathspec:
warn on
>empty strings as pathspec,
>2016-06-22) and 9e4e8a64 (pathspec: die on empty strings as pathspec,
2017-06-
>06).  I think 9e4e8a64, which happened long after 859b7f1d happened, was
not
>careful enough to turn the empty string 859b7f1d added to either a dot or
":/".
>
>A care should be taken as the definition of "everything" depends on
>subcommand.  For the purpose of "add -p", adding a "." to add everything in
the
>current directory is the right thing to do.  But for some other commands,
":/" (i.e.
>really really everything, even things outside the current subdirectory) is
the right
>choice.
>
>We would break commands in a big way if we get this wrong, so add a handful
of
>test pieces to make sure the resulting code still excludes the paths that
are
>expected and includes "everything" else.

Thanks for the heads up. I have to check into this for some scripting. Not
worried but glad to know.
Thanks,
--Randall