The only catch is that we don't really know what our repo contains, so
we have to ignore any possible "not found" status from git-grep.

Signed-off-by: Thomas Rast <trast@student.ethz.ch>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

This introduces a performance testing framework under t/perf/.  It
tries to be as close to the test-lib.sh infrastructure as possible,
and thus should be easy to get used to for git developers.

The following points were considered for the implementation:

1. You usually want to compare arbitrary revisions/build trees against
   each other.  They may not have the performance test under
   consideration, or even the perf-lib.sh infrastructure.

   To cope with this, the 'run' script lets you specify arbitrary
   build dirs and revisions.  It even automatically builds the revisions
   if it doesn't have them at hand yet.

2. Usually you would not want to run all tests.  It would take too
   long anyway.  The 'run' script lets you specify which tests to run;
   or you can also do it manually.  There is a Makefile for
   discoverability and 'make clean', but it is not meant for
   real-world use.

3. Creating test repos from scratch in every test is extremely
   time-consuming, and shipping or downloading such large/weird repos
   is out of the question.

   We leave this decision to the user.  Two different sizes of test
   repos can be configured, and the scripts just copy one or more of
   those (using hardlinks for the object store).  By default it tries
   to use the build tree's git.git repository.

   This is fairly fast and versatile.  Using a copy instead of a clone
   preserves many properties that the user may want to test for, such
   as lots of loose objects, unpacked refs, etc.

Signed-off-by: Thomas Rast <trast@student.ethz.ch>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

This just moves all the user-facing functions to a separate file and
sources that instead.

Signed-off-by: Thomas Rast <trast@student.ethz.ch>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

* jk/git-dir-lookup:
  standardize and improve lookup rules for external local repos

* jk/grep-binary-attribute:
  grep: pre-load userdiff drivers when threaded
  grep: load file data after checking binary-ness
  grep: respect diff attributes for binary-ness
  grep: cache userdiff_driver in grep_source
  grep: drop grep_buffer's "name" parameter
  convert git-grep to use grep_source interface
  grep: refactor the concept of "grep source" into an object
  grep: move sha1-reading mutex into low-level code
  grep: make locking flag global

* nd/pack-objects-parseopt:
  pack-objects: convert to use parse_options()
  pack-objects: remove bogus comment
  pack-objects: do not accept "--index-version=version,"

* dp/i18n-libcharset:
  Makefile: introduce CHARSET_LIB to link with -lcharset

* mh/war-on-extra-refs:
  refs: remove the extra_refs API
  clone: do not add alternate references to extra_refs
  everything_local(): mark alternate refs as complete
  fetch-pack.c: inline insert_alternate_refs()
  fetch-pack.c: rename some parameters from "path" to "refname"
  clone.c: move more code into the "if (refs)" conditional
  t5700: document a failure of alternates to affect fetch

* lt/pull-no-edit:
  "git pull" doesn't know "--edit"

* bl/gitweb-project-filter:
  gitweb: Harden and improve $project_filter page title