[PATCH] revset: introduce the summary predicate

[Yuya Nishihara]

On Fri, 6 Jan 2017 21:29:43 -0500, Matt Harbison wrote:
> > On Jan 6, 2017, at 11:19 AM, Pierre-Yves David <pierre-yves.david at ens-lyon.org> wrote:
> >> On 01/04/2017 07:04 PM, Matt Harbison wrote:
> >> # HG changeset patch
> >> # User Matt Harbison <matt_harbison at yahoo.com>
> >> # Date 1483550016 18000
> >> #      Wed Jan 04 12:13:36 2017 -0500
> >> # Node ID 76d95ab94b9e206363629059fb7824002e19a9e5
> >> # Parent  0064a1eb28e246ded9b726c696d048143d1b23f1
> >> revset: introduce the summary predicate
> >> 
> >> This is similar to the 'desc()' predicate, however the search is limited to the
> >> first line, which I couldn't figure out how to do with the existing
> >> functionality.  Unlike 'desc()', this supports regular expressions.  The
> >> 'matching()' revset already treats the summary line distinctly from the full
> >> description, but that finds similar revisions instead of searching with a
> >> string.
> > 
> > Looks like a great usecase to handle, I want that. However, are there reasons why:
> > 
> > 1) We could not add full pattern support to desc()
> > 2) We could not make this an extra keyworkd parameters of desc()
> > 
> > Multiplying the revset predicate hurts discoverability, having less but more powerful predicate seems useful.
> 
> I share your concern about discoverability.
> 
> I started out editing desc(), but it's explicitly documented as case insensitive.  It seems confusing if matching for literals is case insensitive, but regex is case sensitive for the same predicate. (I vaguely recall that you can make regex case insensitive, but I think that would also surprise the user.)  I meant to mention that maybe we could add pattern support to desc() in addition to this, but forgot.  The other stuff I looked at that supports patterns, like tag(), is case sensitive for both literals and regex.  That makes sense, since those search for identifiers.

Perhaps stringmatcher can have 3 types, icase literal, literal, and re, and
the default of desc() is icase literal for backward compatibility. You can
build a case-insensitive regexp object from a literal pattern.

https://docs.python.org/2/library/re.html#re.I