do not use GIT_TRACE_PACKET=3 in tests

Some test scripts use the GIT_TRACE mechanism to dump
debugging information to descriptor 3 (and point it to a
file using the shell). On Windows, however, bash is unable
to set up descriptor 3. We do not write our trace to the
file, and worse, we may interfere with other operations
happening on descriptor 3, causing tests to fail or even
behave inconsistently.

Prior to commit 97a83fa (upload-pack: remove packet debugging
harness), these tests used GIT_DEBUG_SEND_PACK, which only
supported output to a descriptor. The tests in t5503 were
always broken on Windows, and were marked to be skipped via
the NOT_MINGW prerequisite. In t5700, the tests used to pass
prior to 97a83fa, but only because they were not careful
enough; because we only grepped the trace file, an empty
file looked successful to us. But post-97a83fa, the writing
to descriptor 3 causes "git fetch" to hang (presumably
because we are throwing random bytes into the middle of the
protocol).

Now that we are using the GIT_TRACE mechanism, we can
improve both scripts by asking git to write directly to a
file rather than a descriptor. That fixes the hang in t5700,
and should allow t5503 to successfully run on Windows.

In both cases we now also use "test -s" to double-check that
our trace file actually contains output, which should reduce
the possibility of an erroneously passing test.

Signed-off-by: Jeff King <peff@peff.net>
Tested-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
git-am: show the final log message on "Applying:" indicator

The "Applying:" message "git am" shows to tell the user which patch
is being applied has traditionally been to help identifying the
input, but we started showing the edited result since f23272f3fd84
(git-am -i: report rewritten title, 2007-12-04), because it was
found more confusing to show the original during an interactive
session.

Treat the modification by the applypatch-msg hook in a similar way
and use the edited result in the progress indication, even though
this is usually not interactive.

Signed-off-by: Simon Ruderich <simon@ruderich.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
fixup
Refactor parse_loc

We want to use the same style of -L n,m argument for 'git log -L' as
for git-blame.  Refactor the argument parsing of the range arguments
from builtin/blame.c to the (new) file that will hold the 'git log -L'
logic.

To accommodate different data structures in blame and log -L, the file
contents are abstracted away; parse_range_arg takes a callback that it
uses to get the contents of a line of the (notional) file.

The new test is for a case that made me pause during debugging: the
'blame -L with invalid end' test was the only one that noticed an
outright failure to parse the end *at all*.  So make a more explicit
test for that.

Signed-off-by: Bo Yang <struggleyb.nku@gmail.com>
Signed-off-by: Thomas Rast <trast@student.ethz.ch>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
fixup
Export rewrite_parents() for 'log -L'

The function rewrite_one is used to rewrite a single
parent of the current commit, and is used by rewrite_parents
to rewrite all the parents.

Decouple the dependence between them by making rewrite_one
a callback function that is passed to rewrite_parents. Then
export rewrite_parents for reuse by the line history browser.

We will use this function in line-log.c.

Signed-off-by: Bo Yang <struggleyb.nku@gmail.com>
Signed-off-by: Thomas Rast <trast@student.ethz.ch>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Implement line-history search (git log -L)

This is a rewrite of much of Bo's work, mainly in an effort to split
it into smaller, easier to understand routines.

The algorithm is built around the struct range_set, which encodes a
series of line ranges as intervals [a,b).  This is used in two
contexts:

* A set of lines we are tracking (which will change as we dig through
  history).
* To encode diffs, as pairs of ranges.

The main routine is range_set_map_across_diff().  It processes the
diff between a commit C and some parent P.  It determines which diff
hunks are relevant to the ranges tracked in C, and computes the new
ranges for P.

The algorithm is then simply to process history in topological order
from newest to oldest, computing ranges and (partial) diffs.  At
branch points, we need to merge the ranges we are watching.  We will
find that many commits do not affect the chosen ranges, and mark them
TREESAME (in addition to those already filtered by pathspec limiting).
Another pass of history simplification then gets rid of such commits.

This is wired as an extra filtering pass in the log machinery.  This
currently only reduces code duplication, but should allow for other
simplifications and options to be used.

Finally, we hook a diff printer into the output chain.  Ideally we
would wire directly into the diff logic, to optionally use features
like word diff.  However, that will require some major reworking of
the diff chain, so we completely replace the output with our own diff
for now.

As this was a GSoC project, and has quite some history by now, many
people have helped.  In no particular order, thanks go to

  Jakub Narebski <jnareb@gmail.com>
  Jens Lehmann <Jens.Lehmann@web.de>
  Jonathan Nieder <jrnieder@gmail.com>
  Junio C Hamano <gitster@pobox.com>
  Ramsay Jones <ramsay@ramsay1.demon.co.uk>
  Will Palmer <wmpalmer@gmail.com>

Apologies to everyone I forgot.

Signed-off-by: Bo Yang <struggleyb.nku@gmail.com>
Signed-off-by: Thomas Rast <trast@student.ethz.ch>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
log -L: :pattern:file syntax to find by funcname

This new syntax finds a funcname matching /pattern/, and then takes from there
up to (but not including) the next funcname.  So you can say

  git log -L:main:main.c

and it will dig up the main() function and show its line-log, provided
there are no other funcnames matching 'main'.

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

So far log -L only used the implicit diff filtering by pathspec.  If
the user specifies -M, we cannot do that, and so we simply handed the
whole diff queue (which is approximately 'git show --raw') to
diffcore_std().

Unfortunately this is very slow.  We can optimize a lot if we throw
out files that we know cannot possibly be interesting, in the same
spirit that the pathspec filtering reduces the number of files.

However, in this case, we have to be more careful.  Because we want to
look out for renames, we need to keep all filepairs where something
was deleted.

This is a bit hacky and should really be replaced by equivalent
support in --follow, and just using that.  However, in the meantime it
speeds up 'log -M -L' by an order of magnitude.

Signed-off-by: Thomas Rast <trast@student.ethz.ch>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
CodingGuidelines: our documents are in AsciiDoc

Before talking about notations such as optional [--option] enclosed
in brackets, state that the documents are in AsciiDoc and processed
into other formats.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
Merge branch 'pe/pull-rebase-v-q' into jch

Teach "git pull --rebase" to pass "-v/-q" command line options to
underlying "git rebase".

* pe/pull-rebase-v-q:
  pull: Apply -q and -v options to rebase mode as well
Merge branch 'jc/describe' into jch

The "--match=<pattern>" option of "git describe", when used with
"--all" to allow refs that are not annotated tags to be used as a
base of description, did not restrict the output from the command
to those that match the given pattern.

We may want to have a looser matching that does not restrict to tags,
but that can be done as a follow-up topic; this step is purely a bugfix.

* jc/describe:
  describe: --match=<pattern> must limit the refs even when used with --all
Merge branch 'jl/submodule-deinit' into jch

There was no Porcelain way to say "I no longer am interested in
this submodule", once you express your interest in a submodule with
"submodule init".  "submodule deinit" is the way to do so.

* jl/submodule-deinit:
  submodule: add 'deinit' command

# Conflicts:
# 	Documentation/git-submodule.txt
# 	git-submodule.sh
Merge branch 'ap/maint-diff-rename-avoid-overlap' into jch

The logic used by "git diff -M --stat" to shorten the names of
files before and after a rename did not work correctly when the
common prefix and suffix between the two filenames overlapped.

* ap/maint-diff-rename-avoid-overlap:
  tests: make sure rename pretty print works
  diff: prevent pprint_rename from underrunning input
  diff: Fix rename pretty-print when suffix and prefix overlap
Merge branch 'jc/maint-reflog-expire-clean-mark-typofix' into jch

In "git reflog expire", REACHABLE bit was not cleared from the
correct objects.

* jc/maint-reflog-expire-clean-mark-typofix:
  reflog: fix typo in "reflog expire" clean-up codepath
Merge branch 'jc/push-follow-tag' into jch

The new "--follow-tags" option tells "git push" to push relevant
annotated tags when pushing branches out.

* jc/push-follow-tag:
  push: --follow-tags
  commit.c: use clear_commit_marks_many() in in_merge_bases_many()
  commit.c: add in_merge_bases_many()
  commit.c: add clear_commit_marks_many()

# Conflicts:
# 	builtin/push.c
# 	t/t5516-fetch-push.sh
# 	transport.h
Merge branch 'jk/alias-in-bare' into jch

An aliased command spawned from a bare repository that does not say
it is bare with "core.bare = yes" is treated as non-bare by mistake.

* jk/alias-in-bare:
  setup: suppress implicit "." work-tree for bare repos
  environment: add GIT_PREFIX to local_repo_env
  cache.h: drop LOCAL_REPO_ENV_SIZE
Merge branch 'ks/rfc2047-one-char-at-a-time' into jch

When "format-patch" quoted a non-ascii strings on the header files,
it incorrectly applied rfc2047 and chopped a single character in
the middle of it.

* ks/rfc2047-one-char-at-a-time:
  format-patch: RFC 2047 says multi-octet character may not be split
Merge branch 'jk/empty-archive' into jch

"git archive" reports a failure when asked to create an archive out
of an empty tree.  It would be more intuitive to give an empty
archive back in such a case.

* jk/empty-archive:
  archive: handle commits with an empty tree
  test-lib: factor out $GIT_UNZIP setup
Merge branch 'pw/p4-symlinked-root' into jch

"git p4" did not behave well when the path to the root of the P4
client was not its real path.

* pw/p4-symlinked-root:
  git p4: avoid expanding client paths in chdir
  git p4 test: should honor symlink in p4 client root
  git p4 test: make sure P4CONFIG relative path works