setup_reflog_action: document the rules for using GIT_REFLOG_ACTION

The set_reflog_action helper (in git-sh-setup) is designed to be
used once at the very top of a program, like this in "git am", for
example:

	set_reflog_action am

The helper function sets the given string to GIT_REFLOG_ACTION only
when GIT_REFLOG_ACTION is not yet set.  Thanks to this, "git am",
when run as the top-level program, will use "am" in GIT_REFLOG_ACTION
and the reflog entries made by whatever it does will record the
updates of refs done by "am".

Because of the conditional assignment, when "git am" is run as a
subprogram (i.e. an implementation detail) of "git rebase" that
already sets GIT_REFLOG_ACTION to its own name, the call in "git am"
to the helper function at the beginning will *not* have any effect.

So "git rebase" can do this:

	set_reflog_action rebase
	... do its own preparation, like checking out "onto" commit
        ... decide to do "format-patch" to "am" pipeline
        	git format-patch --stdout >mbox
		git am mbox

and the reflog entries made inside "git am" invocation will say
"rebase", not "am".

Calls to "git" commands that update refs would use GIT_REFLOG_ACTION
to record who did that update.  Most such calls in scripted Porcelains
do not define custom reflog message and rely on GIT_REFLOG_ACTION to
contain its (or its caller's, when it is called as a subprogram) name.

If a scripted Porcelain wants to record a custom reflog message for
a single invocation of "git" command (e.g. when "git rebase" uses
"git checkout" to detach HEAD at the commit a series is to be
replayed on), it needs to set GIT_REFLOG_ACTION to the custom
message and export it while calling the "git" command, but such an
assignment must be restricted to that single "git" invocation and
should not be left behind to affect later codepath.

Document the rules to avoid future confusion.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
checkout: update synopsys and documentation on detaching HEAD

In the synopsis, the second form to detach HEAD at the named commit
labelled the argument as '<commit>'.  While this is technically more
correct, because the feature to detach is not limited to the tip of
a named branch, it was found confusing and did not express the fact
that you have to give `--detach` if you are naming the commit you
want to detach HEAD at with a branch name.

Separate this case into two syntactical forms, mimicking the way how
the DESCRIPTION section shows this usage.  Also update the text that
explains the syntax to name the commit to detach HEAD at to clarify.

Suggested-by: Benjamin Bergman <ben@benbergman.ca>
Helped-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Allow git-filter-branch to process large repositories with lots of branches.

A recommended way to move trees between repositories is to use
git-filter-branch to revise the history for a single tree:

However, this can lead to "argument list too long" errors when the
original repository has many retained branches (>6k)

    /usr/local/git/libexec/git-core/git-filter-branch: line 270:
    /usr/local/git/libexec/git-core/git: Argument list too long
    Could not get the commits

Saving the output from rev-parse and feeding it into rev-list from
its standard input avoids this problem, since the rev-parse output
is not processed as a command line argument.

Signed-off-by: Lee Carver <Lee.Carver@servicenow.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
rm: re-use parse_pathspec's trailing-slash removal

Instead of re-implementing the "remove trailing slashes" loop in
builtin/rm.c just pass PATHSPEC_STRIP_SUBMODULE_SLASH_CHEAP to
parse_pathspec.

Signed-off-by: John Keeping <john@keeping.me.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
reset: handle submodule with trailing slash

When using tab-completion, a directory path will often end with a
trailing slash which currently confuses "git reset" when dealing with
submodules.  Now that we have parse_pathspec we can easily handle this
by simply adding the PATHSPEC_STRIP_SUBMODULE_SLASH_CHEAP flag.

To do this, we need to move the read_cache() call before the
parse_pathspec() call.  All of the existing paths through cmd_reset()
that do not die early already call read_cache() at some point, so there
is no performance impact to doing this in the common case.

Signed-off-by: John Keeping <john@keeping.me.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
name-hash: refactor polymorphic index_name_exists()

Depending upon the absence or presence of a trailing '/' on the incoming
pathname, index_name_exists() checks either if a file is present in the
index or if a directory is represented within the index. Each caller
explicitly chooses the mode of operation by adding or removing a
trailing '/' before invoking index_name_exists().

Since these two modes of operations are disjoint and have no code in
common (one searches index_state.name_hash; the other dir_hash), they
can be represented more naturally as distinct functions: one to search
for a file, and one for a directory.

Splitting index searching into two functions relieves callers of the
artificial burden of having to add or remove a slash to select the mode
of operation; instead they just call the desired function. A subsequent
patch will take advantage of this benefit in order to eliminate the
requirement that the incoming pathname for a directory search must have
a trailing slash.

(In order to avoid disturbing in-flight topics, index_name_exists() is
retained as a thin wrapper dispatching either to index_dir_exists() or
index_file_exists().)

Signed-off-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
employ new explicit "exists in index?" API

Each caller of index_name_exists() knows whether it is looking for a
directory or a file, and can avoid the unnecessary indirection of
index_name_exists() by instead calling index_dir_exists() or
index_file_exists() directly.

Invoking the appropriate search function explicitly will allow a
subsequent patch to relieve callers of the artificial burden of having
to add a trailing '/' to the pathname given to index_dir_exists().

Signed-off-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
name-hash: stop storing trailing '/' on paths in index_state.dir_hash

When 5102c617 (Add case insensitivity support for directories when using
git status, 2010-10-03) added directories to the name-hash there was
only a single hash table in which both real cache entries and leading
directory prefixes were registered. To distinguish between the two types
of entries, directories were stored with a trailing '/'.

2092678c (name-hash.c: fix endless loop with core.ignorecase=true,
2013-02-28), however, moved directories to a separate hash table
(index_state.dir_hash) but retained the (now) redundant trailing '/',
thus callers continue to bear the burden of ensuring the slash's
presence before searching the index for a directory. Eliminate this
redundancy by storing paths in the dir-hash without the trailing '/'.

An important benefit of this change is that it eliminates undocumented
and dangerous behavior of dir.c:directory_exists_in_index_icase() in
which it assumes not only that it can validly access one character
beyond the end of its incoming directory argument, but also that that
character will unconditionally be a '/'. This perilous behavior was
"tolerated" because the string passed in by its lone caller always had a
'/' in that position, however, things broke [1] when 2eac2a4c (ls-files
-k: a directory only can be killed if the index has a non-directory,
2013-08-15) added a new caller which failed to respect the undocumented
assumption.

[1]: http://thread.gmane.org/gmane.comp.version-control.git/232727

Signed-off-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
dir: revert work-around for retired dangerous behavior

directory_exists_in_index_icase() dangerously assumed that it could
access one character beyond the end of its directory argument, and that
that character would unconditionally be '/'.  2eac2a4c (ls-files -k: a
directory only can be killed if the index has a non-directory,
2013-08-15) added a caller which did not respect this undocumented
assumption, and 680be044 (dir.c::test_one_path(): work around
directory_exists_in_index_icase() breakage, 2013-08-23) added a
work-around which temporarily appends a '/' before invoking
directory_exists_in_index_icase().

Since the dangerous behavior of directory_exists_in_index_icase() has
been eliminated, the work-around is now redundant, so retire it (but not
the tests added by the same commit).

Signed-off-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
repack: rewrite the shell script in C

The motivation of this patch is to get closer to a goal of being
able to have a core subset of git functionality built in to git.
That would mean

 * people on Windows could get a copy of at least the core parts
   of Git without having to install a Unix-style shell

 * people using git in on servers with chrooted environments
   do not need to worry about standard tools lacking for shell
   scripts.

This patch is meant to be mostly a literal translation of the
git-repack script; the intent is that later patches would start using
more library facilities, but this patch is meant to be as close to a
no-op as possible so it doesn't do that kind of thing.

Signed-off-by: Stefan Beller <stefanbeller@googlemail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
repack: retain the return value of pack-objects

During the review process of the previous commit (repack: rewrite the
shell script in C), Johannes Sixt proposed to retain any exit codes from
the sub-process, which makes it probably more obvious in case of failure.

As the commit before should behave as close to the original shell
script, the proposed change is put in this extra commit.
The infrastructure however was already setup in the previous commit.
(Having a local 'ret' variable)

Signed-off-by: Stefan Beller <stefanbeller@googlemail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
repack: improve warnings about failure of renaming and removing files

Signed-off-by: Stefan Beller <stefanbeller@googlemail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
clone: send diagnostic messages to stderr

Putting messages like "Cloning into.." and "done" on stdout
is un-Unix and uselessly clutters the stdout channel. Send
them to stderr.

We have to tweak two tests to accommodate this:

  1. t5601 checks for doubled output due to forking, and
     doesn't actually care where the output goes; adjust it
     to check stderr.

  2. t5702 is trying to test whether progress output was
     sent to stderr, but naively does so by checking
     whether stderr produced any output. Instead, have it
     look for "%", a token found in progress output but not
     elsewhere (and which lets us avoid hard-coding the
     progress text in the test).

This should not regress any scripts that try to parse the
current output, as the output is already internationalized
and therefore unstable.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
clone: treat "checking connectivity" like other progress

When stderr does not point to a tty, we typically suppress
"we are now in this phase" progress reporting (e.g., we ask
the server not to send us "counting objects" and the like).

The new "checking connectivity" message is in the same vein,
and should be suppressed. Since clone relies on the
transport code to make the decision, we can simply sneak a
peek at the "progress" field of the transport struct. That
properly takes into account both the verbosity and progress
options we were given, as well as the result of isatty().

Note that we do not set up that progress flag for a local
clone, as we do not fetch using the transport at all. That's
acceptable here, though, because we also do not perform a
connectivity check in that case.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
clone: always set transport options

A clone will always create a transport struct, whether we
are cloning locally or using an actual protocol. In the
local case, we only use the transport to get the list of
refs, and then transfer the objects out-of-band.

However, there are many options that we do not bother
setting up in the local case. For the most part, these are
noops, because they only affect the object-fetching stage
(e.g., the --depth option).  However, some options do have a
visible impact. For example, giving the path to upload-pack
via "-u" does not currently work for a local clone, even
though we need upload-pack to get the ref list.

We can just drop the conditional entirely and set these
options for both local and non-local clones. Rather than
keep track of which options impact the object versus the ref
fetching stage, we can simply let the noops be noops (and
the cost of setting the options in the first place is not
high).

The one exception is that we also check that the transport
provides both a "get_refs_list" and a "fetch" method. We
will now be checking the former for both cases (which is
good, since a transport that cannot fetch refs would not
work for a local clone), and we tweak the conditional to
check for a "fetch" only when we are non-local.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
format-patch: print in-body "From" only when needed

Commit a908047 taught format-patch the "--from" option,
which places the author ident into an in-body from header,
and uses the committer ident in the rfc822 from header.  The
documentation claims that it will omit the in-body header
when it is the same as the rfc822 header, but the code never
implemented that behavior.

This patch completes the feature by comparing the two idents
and doing nothing when they are the same (this is the same
as simply omitting the in-body header, as the two are by
definition indistinguishable in this case). This makes it
reasonable to turn on "--from" all the time (if it matches
your particular workflow), rather than only using it when
exporting other people's patches.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
t4254: modernize tests

- Don't start tests with 'test $? = 0' to catch preparation done
  outside the test_expect_success block.

- Move writing the bogus patch and the expected output into the
  appropriate test_expect_success blocks.

- Use the test_must_fail helper instead of manually checking for
  non-zero exit code.

- Use the debug-friendly test_path_is_file helper instead of 'test -f'.

- No space after '>'.

Signed-off-by: SZEDER Gábor <szeder@ira.uka.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Merge branch 'es/rebase-i-respect-core-commentchar' into maint

* es/rebase-i-respect-core-commentchar:
  rebase -i: fix cases ignoring core.commentchar
Merge branch 'rt/rebase-p-no-merge-summary' into maint

* rt/rebase-p-no-merge-summary:
  rebase --preserve-merges: ignore "merge.log" config
Merge branch 'es/rebase-i-no-abbrev' into maint

* es/rebase-i-no-abbrev:
  rebase -i: fix short SHA-1 collision
  t3404: rebase -i: demonstrate short SHA-1 collision
  t3404: make tests more self-contained

Conflicts:
	t/t3404-rebase-interactive.sh