[PATCH 0 of 2] fast manifest based grep

[Steve Borho]

On Sat, May 15, 2010 at 12:55 PM, Matt Mackall <mpm at selenic.com> wrote:
> On Fri, 2010-05-14 at 15:54 -0500, steve at borho.org wrote:
>> These two patches add fast manifest based grep methods for when the
>> user is not interested in per-line annotation data.  Especially handy
>> for platforms without a native grep command.
>
> Please:
>
> - remind us all / show us how the crazy old command worked

By default, the grep command has always done a filelog search for each
match in order to report a changeset for each match.  For example:

% hg grep -I contrib progress
contrib/check-code.py:10905:    (r'ui\.(status|progress|write|note)\([\'\"]x',
contrib/shrink-revlog.py:10724:            ui.progress(_('reading'),
rev, total=len(rl))
contrib/shrink-revlog.py:10724:        ui.progress(_('reading'), None)
<snip>

code-check.py was modified in 10905, but it did not involve the line
being shown.  10905 just happens to be the most recent revision to
touch that file.  Also note that grep completely ignores uncommitted
changes in the working copy.

The behavior of grep -r is even less useful.  Instead of searching the
contents of the files as they appeared in that revision, it restricts
the search to files modified in that revision.

% hg grep -r 0.9 progress
<nothing>

> - tell us / show us how your change is different

That command:  'hg grep -I contrib progress' took 2.14s on my machine.
 After my patch, by directly searching the working directory and not
reporting a meaningless revision number, the same command takes 0.22s.

'hg grep -c . -I progress' (reading the parent revision contents
instead of the working copy) takes 0.20s

grep --change rev does what the user would expect; searching the files
as they appeared in that revision.

% hg grep -c 0.9 progress
contrib/hgk:    global findinprogress
contrib/hgk:    if {[info exists findinprogress]} {
contrib/hgk:	unset findinprogress
<snip>

> - tell us why changing the current behavior is acceptable

In effect, these patches change four things and only the first two
change existing behavior.

1) No longer report a revision number by default
2) Include working copy changes by default
3) Add a --change argument that does what users expect
4) adds a progress bar to the default and changeset searches

According to informal polls on IRC, not many people use the grep
command because of its current quirks.  I think my changes make the
behavior more useful, discoverable, and much faster.

--
Steve Borho