[PATCH] revset: add regular expression support to 'desc()'

[Sean Farley]

Matt Harbison <mharbison72 at gmail.com> writes:

> # HG changeset patch
> # User Matt Harbison <matt_harbison at yahoo.com>
> # Date 1483842392 18000
> #      Sat Jan 07 21:26:32 2017 -0500
> # Node ID 7347f75339503a8266285ac12412ac5f104d4df0
> # Parent  4ab19763d71c2bb9a239dff523b18ed860e34563
> revset: add regular expression support to 'desc()'
>
> The legacy behavior of doing a case insensitive match for literals is preserved
> for BC.  This includes with the new 'literal:' prefix for user simplicity.
>
> There are two other revsets that do case insensitive matches- 'user()' (and its
> alias 'author()'), and 'keyword()'.  The 'keyword()' predicate only supports
> literals, so its behavior isn't interesting right now.  The 'user()' predicate
> is documented to support regex, but ends up lowercasing both the needle and the
> haystack, effectively making it a case insensitive regex.  That surprised me,
> since it's the only instance of that behavior.  I'm not sure if this should
> conform to that because we are stuck with BC, or if that should be considered a
> bug and changed.  If we can't change it, that probably precludes adding an
> insensitive regex matcher [1].
>
> [1] https://www.mercurial-scm.org/pipermail/mercurial-devel/2017-January/092070.html

I was a bit confused before because I was mixing up templates with
revsets. If I follow your previous patch, you want to have a revset that
just searches the first line of the description, correct?

If that's correct, it would seem that our choices with template
functionality might be a precedent for this, no?