This adds a new form of overview diffstat output, doing something that I
have occasionally ended up doing manually (and badly, because it's
actually pretty nasty to do), and that I think is very useful for an
project like the kernel that has a fairly deep and well-separated
directory structure with semantic meaning.

What I mean by that is that it's often interesting to see exactly which
sub-directories are impacted by a patch, and to what degree - even if you
don't perhaps care so much about the individual files themselves.

What makes the concept more interesting is that the "impact" is often
hierarchical: in the kernel, for example, something could either have a
very localized impact to "fs/ext3/" and then it's interesting to see that
such a patch changes mostly that subdirectory, but you could have another
patch that changes some generic VFS-layer issue which affects _many_
subdirectories that are all under "fs/", but none - or perhaps just a
couple of them - of the individual filesystems are interesting in
themselves.

So what commonly happens is that you may have big changes in a specific
sub-subdirectory, but still also significant separate changes to the
subdirectory leading up to that - maybe you have significant VFS-level
changes, but *also* changes under that VFS layer in the NFS-specific
directories, for example. In that case, you do want the low-level parts
that are significant to show up, but then the insignificant ones should
show up as under the more generic top-level directory.

This patch shows all of that with "--dirstat". The output can be either
something simple like

        commit 81772fe...
        Author: Thomas Gleixner <tglx@linutronix.de>
        Date:   Sun Feb 10 23:57:36 2008 +0100

            x86: remove over noisy debug printk

            pageattr-test.c contains a noisy debug printk that people reported.
            The condition under which it prints (randomly tapping into a mem_map[]
            hole and not being able to c_p_a() there) is valid behavior and not
            interesting to report.

            Remove it.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Acked-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

         100.0% arch/x86/mm/

or something much more complex like

        commit e231c2e...
        Author: David Howells <dhowells@redhat.com>
        Date:   Thu Feb 7 00:15:26 2008 -0800

            Convert ERR_PTR(PTR_ERR(p)) instances to ERR_CAST(p)

	  20.5% crypto/
	   7.6% fs/afs/
	   7.6% fs/fuse/
	   7.6% fs/gfs2/
	   5.1% fs/jffs2/
	   5.1% fs/nfs/
	   5.1% fs/nfsd/
	   7.6% fs/reiserfs/
	  15.3% fs/
	   7.6% net/rxrpc/
	  10.2% security/keys/

where that latter example is an example of significant work in some
individual fs/*/ subdirectories (like the patches to reiserfs accounting
for 7.6% of the whole), but then discounting those individual filesystems,
there's also 15.3% other "random" things that weren't worth reporting on
their oen left over under fs/ in general (either in that directory itself,
or in subdirectories of fs/ that didn't have enough changes to be reported
individually).

I'd like to stress that the "15.3% fs/" mentioned above is the stuff that
is under fs/ but that was _not_ significant enough to report on its own.
So the above does _not_ mean that 15.3% of the work was under fs/ per se,
because that 15.3% does *not* include the already-reported 7.6% of afs,
7.6% of fuse etc.

If you want to enable "cumulative" directory statistics, you can use the
"--cumulative" flag, which adds up percentages recursively even when
they have been already reported for a sub-directory.  That cumulative
output is disabled if *all* of the changes in one subdirectory come from
a deeper subdirectory, to avoid repeating subdirectories all the way to
the root.

For an example of the cumulative reporting, the above commit becomes

	commit e231c2e...
	Author: David Howells <dhowells@redhat.com>
	Date:   Thu Feb 7 00:15:26 2008 -0800

	    Convert ERR_PTR(PTR_ERR(p)) instances to ERR_CAST(p)

	  20.5% crypto/
	   7.6% fs/afs/
	   7.6% fs/fuse/
	   7.6% fs/gfs2/
	   5.1% fs/jffs2/
	   5.1% fs/nfs/
	   5.1% fs/nfsd/
	   7.6% fs/reiserfs/
	  61.5% fs/
	   7.6% net/rxrpc/
	  10.2% security/keys/

in which the commit percentages now obviously add up to much more than
100%: now the changes that were already reported for the sub-directories
under fs/ are then cumulatively included in the whole percentage of fs/
(ie now shows 61.5% as opposed to the 15.3% without the cumulative
reporting).

The default reporting limit has been arbitrarily set at 3%, which seems
to be a pretty good cut-off, but you can specify the cut-off manually by
giving it as an option parameter (eg "--dirstat=5" makes the cut-off be
at 5% instead)

NOTE! The percentages are purely about the total lines added and removed,
not anything smarter (or dumber) than that. Also note that you should not
generally expect things to add up to 100%: not only does it round down, we
don't report leftover scraps (they add up to the top-level change count,
but we don't even bother reporting that, it only reports subdirectories).

Quite frankly, as a top-level manager this is really convenient for me,
but it's going to be very boring for git itself since there are few
subdirectories. Also, don't expect things to make tons of sense if you
combine this with "-M" and there are cross-directory renames etc.

But even for git itself, you can get some fun statistics. Try out

        git log --dirstat

and see the occasional mentions of things like Documentation/, git-gui/,
gitweb/ and gitk-git/. Or try out something like

        git diff --dirstat v1.5.0..v1.5.4

which does kind of git an overview that shows *something*. But in general,
the output is more exciting for big projects with deeper structure, and
doing a

        git diff --dirstat v2.6.24..v2.6.25-rc1

on the kernel is what I actually wrote this for!
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

The diff porcelain uses git_diff_ui_config to set
porcelain-ish config options, like automatically turning on
color. The plumbing specifically avoids calling this
function, since it doesn't want things like automatic color
or rename detection.

However, some diff options should be set for both plumbing
and porcelain. For example, one can still turn on color in
git-diff-files using the --color command line option. This
means we want the color config from color.diff.* (so that
once color is on, we use the user's preferred scheme), but
_not_ the color.diff variable.

We split the diff config into "ui" and "basic", where
"basic" is suitable for use by plumbing (so _most_ things
affecting the output should still go into the "ui" part).
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

With the new options "--src-prefix=<prefix>", "--dst-prefix=<prefix>"
and "--no-prefix", you can now control the path prefixes of the diff
machinery.  These used to by hardwired to "a/" for the source prefix
and "b/" for the destination prefix.

Initial patch by Pascal Obry.  Sane option names suggested by Linus.
Signed-off-by: NJohannes Schindelin <johannes.schindelin@gmx.de>
Acked-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

There is no reason --exit-code and --check-diff must be mutually
exclusive, so assign different bits to different results and allow them
to be returned from the command.  Introduce diff_result_code() to factor
out the common code to decide final status code based on diffopt
settings and use it everywhere.

Update tests to match the above fix.

Turning pager off when "diff --check" is used is a regression.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

"git diff" has a --check option that can be used to check for whitespace
problems but it only reported by printing warnings to the
console.

Now when the --check option is used we give a non-zero exit status,
making "git diff --check" nicer to use in scripts and hooks.
Signed-off-by: NWincent Colaiuta <win@wincent.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

reverse_diff was a bit-value in disguise, it's merged in the flags now.
Signed-off-by: NPierre Habouzit <madcoder@debian.org>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Earlier in commit 0781b8a9
(add_file_to_index: skip rehashing if the cached stat already
matches), add_file_to_index() were taught not to re-add the path
if it already matches the index.

The change meant well, but was not executed quite right.  It
used ie_modified() to see if the file on the work tree is really
different from the index, and skipped adding the contents if the
function says "not modified".

This was wrong.  There are three possible comparison results
between the index and the file in the work tree:

 - with lstat(2) we _know_ they are different.  E.g. if the
   length or the owner in the cached stat information is
   different from the length we just obtained from lstat(2), we
   can tell the file is modified without looking at the actual
   contents.

 - with lstat(2) we _know_ they are the same.  The same length,
   the same owner, the same everything (but this has a twist, as
   described below).

 - we cannot tell from lstat(2) information alone and need to go
   to the filesystem to actually compare.

The last case arises from what we call 'racy git' situation,
that can be caused with this sequence:

    $ echo hello >file
    $ git add file
    $ echo aeiou >file ;# the same length

If the second "echo" is done within the same filesystem
timestamp granularity as the first "echo", then the timestamp
recorded by "git add" and the timestamp we get from lstat(2)
will be the same, and we can mistakenly say the file is not
modified.  The path is called 'racily clean'.  We need to
reliably detect racily clean paths are in fact modified.

To solve this problem, when we write out the index, we mark the
index entry that has the same timestamp as the index file itself
(that is the time from the point of view of the filesystem) to
tell any later code that does the lstat(2) comparison not to
trust the cached stat info, and ie_modified() then actually goes
to the filesystem to compare the contents for such a path.

That's all good, but it should not be used for this "git add"
optimization, as the goal of "git add" is to actually update the
path in the index and make it stat-clean.  With the false
optimization, we did _not_ cause any data loss (after all, what
we failed to do was only to update the cached stat information),
but it made the following sequence leave the file stat dirty:

    $ echo hello >file
    $ git add file
    $ echo hello >file ;# the same contents
    $ git add file

The solution is not to use ie_modified() which goes to the
filesystem to see if it is really clean, but instead use
ie_match_stat() with "assume racily clean paths are dirty"
option, to force re-adding of such a path.

There was another problem with "git add -u".  The codepath
shares the same issue when adding the paths that are found to be
modified, but in addition, it asked "git diff-files" machinery
run_diff_files() function (which is "git diff-files") to list
the paths that are modified.  But "git diff-files" machinery
uses the same ie_modified() call so that it does not report
racily clean _and_ actually clean paths as modified, which is
not what we want.

The patch allows the callers of run_diff_files() to pass the
same "assume racily clean paths are dirty" option, and makes
"git-add -u" codepath to use that option, to discover and re-add
racily clean _and_ actually clean paths.

We could further optimize on top of this patch to differentiate
the case where the path really needs re-adding (i.e. the content
of the racily clean entry was indeed different) and the case
where only the cached stat information needs to be refreshed
(i.e. the racily clean entry was actually clean), but I do not
think it is worth it.

This patch applies to maint and all the way up.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

ce_match_stat() can be told:

 (1) to ignore CE_VALID bit (used under "assume unchanged" mode)
     and perform the stat comparison anyway;

 (2) not to perform the contents comparison for racily clean
     entries and report mismatch of cached stat information;

using its "option" parameter.  Give them symbolic constants.

Similarly, run_diff_files() can be told not to report anything
on removed paths.  Also give it a symbolic constant for that.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

When we compare two non-tracked files, or explicitly
specify --no-index, the suggestion to run git-status
is not helpful.

The patch adds a new diff_options bitfield member, no_index, that
is used instead of the special value of -2 of the rev_info field
max_count to indicate that the index is not to be used.  This makes
it possible to pass that flag down to diffcore_skip_stat_unmatch(),
which only has one diff_options parameter.

This could even become a cleanup if we removed all assignments of
max_count to a value of -2 (viz. replacement of a magic value with
a self-documenting field name) but I didn't dare to do that so late
in the rc game..

The no_index bit, if set, then tells diffcore_skip_stat_unmatch()
to not account for any skipped stat-mismatches, which avoids the
suggestion to run git-status.
Signed-off-by: NRene Scharfe <rene.scharfe@lsfire.ath.cx>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

After starting to edit a working tree file but later when your edit ends
up identical to the original (this can also happen when you ran a
wholesale regexp replace with something like "perl -i" that does not
actually modify many of the paths), "git diff" between the index and the
working tree outputs many "empty" diffs that show "diff --git" headers
and nothing else, because these paths are stat-dirty.  While it was a
way to warn the user that the earlier action of the user made the index
ineffective as an optimization mechanism, it was felt too loud for the
purpose of warning even to experienced users, and also resulted in
confusing people new to git.

This replaces the "empty" diffs with a single warning message at the
end.  Having many such paths hurts performance, and you can run
"git-update-index --refresh" to update the lstat(2) information recorded
in the index in such a case.  "git-status" does so as a side effect, and
that is more familiar to the end-user, so we recommend it to them.

The change affects only "git diff" that outputs patch text, because that
is where the annoyance of too many "empty" diff is most strongly felt,
and because the warning message can be safely ignored by downstream
tools without getting mistaken as part of the patch.  For the low-level
"git diff-files" and "git diff-index", the traditional behaviour is
retained.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Ok, I've really held off doing this too damn long, because I'm lazy, and I
was always hoping that somebody else would do it.

But no, people keep asking for it, but nobody actually did anything, so I
decided I might as well bite the bullet, and instead of telling people
they could add a "--follow" flag to "git log" to do what they want to do,
I decided that it looks like I just have to do it for them..

The code wasn't actually that complicated, in that the diffstat for this
patch literally says "70 insertions(+), 1 deletions(-)", but I will have
to admit that in order to get to this fairly simple patch, you did have to
know and understand the internal git diff generation machinery pretty
well, and had to really be able to follow how commit generation interacts
with generating patches and generating the log.

So I suspect that while I was right that it wasn't that hard, I might have
been expecting too much of random people - this patch does seem to be
firmly in the core "Linus or Junio" territory.

To make a long story short: I'm sorry for it taking so long until I just
did it.

I'm not going to guarantee that this works for everybody, but you really
can just look at the patch, and after the appropriate appreciative noises
("Ooh, aah") over how clever I am, you can then just notice that the code
itself isn't really that complicated.

All the real new code is in the new "try_to_follow_renames()" function. It
really isn't rocket science: we notice that the pathname we were looking
at went away, so we start a full tree diff and try to see if we can
instead make that pathname be a rename or a copy from some other previous
pathname. And if we can, we just continue, except we show *that*
particular diff, and ever after we use the _previous_ pathname.

One thing to look out for: the "rename detection" is considered to be a
singular event in the _linear_ "git log" output! That's what people want
to do, but I just wanted to point out that this patch is *not* carrying
around a "commit,pathname" kind of pair and it's *not* going to be able to
notice the file coming from multiple *different* files in earlier history.

IOW, if you use "git log --follow", then you get the stupid CVS/SVN kind
of "files have single identities" kind of semantics, and git log will just
pick the identity based on the normal move/copy heuristics _as_if_ the
history could be linearized.

Put another way: I think the model is broken, but given the broken model,
I think this patch does just about as well as you can do. If you have
merges with the same "file" having different filenames over the two
branches, git will just end up picking _one_ of the pathnames at the point
where the newer one goes away. It never looks at multiple pathnames in
parallel.

And if you understood all that, you probably didn't need it explained, and
if you didn't understand the above blathering, it doesn't really mtter to
you. What matters to you is that you can now do

	git log -p --follow builtin-rev-list.c

and it will find the point where the old "rev-list.c" got renamed to
"builtin-rev-list.c" and show it as such.
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Signed-off-by: NJunio C Hamano <gitster@pobox.com>

This enhances the attributes mechanism so that external programs
meant for existing GIT_EXTERNAL_DIFF interface can be specifed
per path.

To configure such a custom diff driver, first define a custom
diff driver in the configuration:

	[diff "my-c-diff"]
		command = <<your command string comes here>>

Then mark the paths that you want to use this custom driver
using the attribute mechanism.

	*.c	diff=my-c-diff

The intent of this separation is that the attribute mechanism is
used for specifying the type of the contents, while the
configuration mechanism is used to define what needs to be done
to that type of the contents, which would be specific to both
platform and personal taste.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

This adds the command line option 'quiet' to tell 'git diff-*'
that we are not interested in the actual diff contents but only
want to know if there is any change.  This option automatically
turns --exit-code on, and turns off output formatting, as it
does not make much sense to show the first hit we happened to
have found.

The --quiet option is silently turned off (but --exit-code is
still in effect, so is silent output) if postprocessing filters
such as pickaxe and diff-filter are used.  For all practical
purposes I do not think of a reason to want to use these filters
and not viewing the diff output.

The backends have not been taught about the option with this patch.
That is a topic for later rounds.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

This was only used by diff-tree-helper program, whose purpose
was to translate a raw diff to a patch.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

This introduces a new command-line option: --exit-code. The diff
programs will return 1 for differences, return 0 for equality, and
something else for errors.
Signed-off-by: NAlex Riesen <raa.lkml@gmail.com>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

When specifying an absolute path, or a relative path pointing outside
the working tree, do not fail, but roll your own diffopt parsing,
and execute a --no-index diff.
Signed-off-by: NJohannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

diff sets the exit status to 0 when no changes were found, to 1
when changes were found, and 2 means error.

We imitate this to be able to use "git diff" in the test scripts.
(Actually, keeping in line with the rest of git, -1 is returned
on error, which corresponds to an exit status 255).

To find out if the diff is not empty, a member called
"found_changes" was introduced in struct diff_options, which is
set in builtin_diff() and fn_out_consume().
Signed-off-by: NJohannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

With this flag and given two paths, git-diff-files behaves as a GNU diff
lookalike (plus the git goodies like --check, colour, etc.).  This flag
is also available in git-diff.  It also works outside of a git repository.

In addition, if git-diff{,-files} is called without revision or stage
parameter, and with exactly two paths at least one of which is not tracked,
the default is --no-index.

So, you can now say

	git diff /etc/inittab /etc/fstab

and it actually works!

This also unifies the duplicated argument parsing between cmd_diff_files()
and builtin_diff_files().
Signed-off-by: NJohannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

Warning: this changes the semantics.

This makes "git blame" without any positive rev to start digging
from the working tree copy, which is made into a fake commit
whose sole parent is the HEAD.

It also adds --contents <file> option to pretend as if the
working tree copy has the contents of the named file.  You can
use '-' to make the command read from the standard input.

If you want the command to start annotating from the HEAD
commit, you need to explicitly give HEAD parameter.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

This updates the way diffcore represents an unmerged pair
somewhat.  It used to be that entries with mode=0 on both sides
were used to represent an unmerged pair, but now it has an
explicit flag.  This is to allow diff-index --cached to report
the entry from the tree when the path is unmerged in the index.

This is used in updating "git reset <tree> -- <path>" to restore
absense of the path in the index from the tree.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

It is nicer to let the user know when a commit succeeded all the time,
not only the first time.  Also the commit sha1 is much more useful than
the tree sha1 in this case.

This patch also introduces a -q switch to supress this message as well
as the summary of created/deleted files.
Signed-off-by: NNicolas Pitre <nico@cam.org>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

The idea is that we are interested in renaming into only one path, so
we do not care about renames that happen elsewhere.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

This patch on top of 'next' makes built-in git-cherry handle root
commits.

It moves the static function log-tree.c::diff_root_tree() to
tree-diff.c and makes it more similar to diff_tree_sha1() by
shuffling around arguments and factoring out the call to
log_tree_diff_flush().  Consequently the name is changed to
diff_root_tree_sha1().  It is a version of diff_tree_sha1() that
compares the empty tree (= root tree) against a single 'real' tree.

This function is then used in get_patch_id() to compute patch IDs
for initial commits instead of SEGFAULTing, as the current code
does if confronted with parentless commits.
Signed-off-by: NRene Scharfe <rene.scharfe@lsrfire.ath.cx>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

[jc: with documentation from Jakub]
Signed-off-by: NJunio C Hamano <junkio@cox.net>

This adds two parameters to "diff --stat".

 . --stat-width=72 tells that the page should fit on 72-column output.

 . --stat-name-width=30 tells that the filename part is limited
   to 30 columns.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

This adds DIFF_WHITESPACE color class (default = reverse red) to
colored diff output to let you catch common whitespace errors.

 - trailing whitespaces at the end of line
 - a space followed by a tab in the indent
Signed-off-by: NJunio C Hamano <junkio@cox.net>

Users can request the DIFF_FORMAT_CALLBACK output format to get a callback
consisting of the whole diff_queue_struct.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

With this option, the changed words are shown inline. For example,
if a file containing "This is foo" is changed to "This is bar", the diff
will now show "This is " in plain text, "foo" in red, and "bar" in green.
Signed-off-by: NJohannes Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

When paging through the output of git-whatchanged, the color cues help to
visually navigate within a diff. However, it is difficult to notice when a
new commit starts, because the commit and log are shown in the "normal"
color. This patch colorizes the 'commit' line, customizable through
diff.colors.commit and defaulting to yellow.

As a side effect, some of the diff color engine (slot enum, get_color) has
become accessible outside of diff.c.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

The Porcelainish has become so much usable as the UI that there
is not much reason people should be using the core programs by
hand anymore.  At this point we are better off making the
behaviour of the core programs predictable by keeping them
unaffected by the configuration variables.  Otherwise they will
become very hard to use as reliable building blocks.

For example, "git-commit -a" internally uses git-diff-files to
figure out the set of paths that need to be updated in the
index, and we should never allow diff.renames that happens to be
in the configuration to interfere (or slow down the process).

The UI level configuration such as showing renamed diff and
coloring are still honored by the Porcelainish ("git log" family
and "git diff"), but not by the core anymore.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

Signed-off-by: NStephan Feder <sf@b-i-t.de>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

Add new item text to struct diff_options.
If set then do not try to detect binary files.
Signed-off-by: NStephan Feder <sf@b-i-t.de>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

Add msg_sep variable to struct diff_options.  msg_sep is printed after
commit message.  Default is "\n", format-patch sets it to "---\n".

This also removes the second argument from show_log() because all
callers derived it from the first argument:

    show_log(rev, rev->loginfo, ...
Signed-off-by: NTimo Hirvonen <tihirvon@gmail.com>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

DIFF_FORMAT_* are now bit-flags instead of enumerated values.
Signed-off-by: NTimo Hirvonen <tihirvon@gmail.com>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

Call it like this:

unsigned char id[20];
if (diff_flush_patch_id(diff_options, id))
	printf("And the patch id is: %s\n", sha1_to_hex(id));
Signed-off-by: NJohannes Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

This adds -b (--ignore-space-change) and -w (--ignore-all-space) flags to
diff. The main part of the patch is teaching libxdiff about it.

[jc: renamed xdl_line_match() to xdl_recmatch() since the former is used
 for different purposes in xpatchi.c which is in the parts of the upstream
 source we do not use.]
Signed-off-by: NJohannes Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

This patch is a slightly adjusted version of Junio's patch:
http://www.gelato.unsw.edu.au/archives/git/0604/19354.html

However, instead of using a config variable, this patch makes it available
as a diff option.
Signed-off-by: NJohannes Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

This patch touches a couple of files, because it adds options to print a
custom text just after the subject of a commit, and just after the
diffstat.

[jc: made "many dashes" used as the boundary leader into a single
 variable, to reduce the possibility of later tweaks to miscount the
 number of dashes to break it.]
Signed-off-by: NJohannes Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

Actually, it is a diff option now, so you can say

	git diff --check

to ask if what you are about to commit is a good patch.

[jc: this also would work for fmt-patch, but the point is that
 the check is done before making a commit.  format-patch is run
 from an already created commit, and that is too late to catch
 whitespace damaged change.]
Signed-off-by: NJohannes Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: NJunio C Hamano <junkio@cox.net>