'update-index --refresh' and 'diff-index' (without --cached) don't honor
the core.preloadindex setting yet. Porcelain commands using these (such as
git [svn] rebase) suffer from this, especially on Windows.
Use read_cache_preload to improve performance.
Additionally, in builtin/diff.c, don't preload index status if we don't
access the working copy (--cached).
Results with msysgit on WebKit repo (2GB in 200k files):
| update-index | diff-index | rebase
----------------+--------------+------------+---------
msysgit-v1.8.0 | 9.157s | 10.536s | 42.791s
+ preloadindex | 9.157s | 10.536s | 28.725s
+ this patch | 2.329s | 2.752s | 15.152s
+ fscache [1] | 0.731s | 1.171s | 8.877s
[1] https://github.com/kblees/git/tree/kb/fscache-v3
Thanks-to: Albert Krawczyk <pro-logic@optusnet.com.au>
Signed-off-by: Karsten Blees <blees@dcon.de>
Signed-off-by: Jeff King <peff@peff.net>
This is used by diff-no-index.c, part of libgit.a while it stays in
builtin/diff.c. Move it to diff.c so that we won't get undefined
reference if a program that uses libgit.a happens to pull it in.
While at it, move check_pager from git.c to pager.c. It makes more
sense there and pager.c is also part of libgit.a
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Jeff King <peff@peff.net>
diff_setup_done() has historically returned an error code, but lost
the last nonzero return in 943d5b7 (allow diff.renamelimit to be set
regardless of -M/-C, 2006-08-09). The callers were in a pretty
confused state: some actually checked for the return code, and some
did not.
Let it return void, and patch all callers to take this into account.
This conveniently also gets rid of a handful of different(!) error
messages that could never be triggered anyway.
Note that the function can still die().
Signed-off-by: Thomas Rast <trast@student.ethz.ch>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The diff code represents paths using the diff_filespec
struct. This struct has a sha1 to represent the sha1 of the
content at that path, as well as a sha1_valid member which
indicates whether its sha1 field is actually useful. If
sha1_valid is not true, then the filespec represents a
working tree file (e.g., for the no-index case, or for when
the index is not up-to-date).
The diff_filespec is only used internally, though. At the
interfaces to the diff subsystem, callers feed the sha1
directly, and we create a diff_filespec from it. It's at
that point that we look at the sha1 and decide whether it is
valid or not; callers may pass the null sha1 as a sentinel
value to indicate that it is not.
We should not typically see the null sha1 coming from any
other source (e.g., in the index itself, or from a tree).
However, a corrupt tree might have a null sha1, which would
cause "diff --patch" to accidentally diff the working tree
version of a file instead of treating it as a blob.
This patch extends the edges of the diff interface to accept
a "sha1_valid" flag whenever we accept a sha1, and to use
that flag when creating a filespec. In some cases, this
means passing the flag through several layers, making the
code change larger than would be desirable.
One alternative would be to simply die() upon seeing
corrupted trees with null sha1s. However, this fix more
directly addresses the problem (while bogus sha1s in a tree
are probably a bad thing, it is really the sentinel
confusion sending us down the wrong code path that is what
makes it devastating). And it means that git is more capable
of examining and debugging these corrupted trees. For
example, you can still "diff --raw" such a tree to find out
when the bogus entry was introduced; you just cannot do a
"--patch" diff (just as you could not with any other
corrupted tree, as we do not have any content to diff).
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
git-diff does not rely on the git wrapper to setup its
pager; instead, it sets it up on its own after seeing
whether --quiet or --exit-code has been specified. After
diff_no_index was split off from cmd_diff, commit b3fde6c
(git diff --no-index: default to page like other diff
frontends, 2008-05-26) duplicated the one-liner from
cmd_diff to turn on the pager.
Later, commit 8f0359f (Allow pager of diff command be
enabled/disabled, 2008-07-21) taught the the version in
cmd_diff to respect the pager.diff config, but the version
in diff_no_index was left behind. This meant that
git -c pager.diff=0 diff a b
would not use a pager, but
git -c pager.diff=0 diff --no-index a b
would. Let's fix it by factoring out a common function.
While we're there, let's update the antiquated comment,
which claims that the pager interferes with propagating the
exit code; this has not been the case since ea27a18 (spawn
pager via run_command interface, 2008-07-22).
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This macro already evaluates to the correct type, as it
casts the string literal to "unsigned char *" itself
(and callers who want the literal can use the _LITERAL
form).
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Config option diff.statGraphWidth=<width> is equivalent to
--stat-graph-width=<width>, except that the config option is ignored
by format-patch.
For the graph-width limiting to be usable, it should happen
'automatically' once configured, hence the config option.
Nevertheless, graph width limiting only makes sense when used on a
wide terminal, so it should not influence the output of format-patch,
which adheres to the 80-column standard.
Signed-off-by: Zbigniew Jędrzejewski-Szmek <zbyszek@in.waw.pl>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Default to the real terminal width for diff --stat output, instead
of the hard-coded 80 columns.
Some projects (especially in Java), have long filename paths, with
nested directories or long individual filenames. When files are
renamed, the filename part in stat output can be almost useless. If
the middle part between { and } is long (because the file was moved to
a completely different directory), then most of the path would be
truncated.
It makes sense to detect and use the full terminal width and display
full filenames if possible.
The are commands like diff, show, and log, which can adapt the output
to the terminal width. There are also commands like format-patch,
whose output should be independent of the terminal width. Since it is
safer to use the 80-column default, the real terminal width is only
used if requested by the calling code by setting diffopts.stat_width=-1.
Normally this value is 0, and can be set by the user only to a
non-negative value, so -1 is safe to use internally.
This patch only changes the diff builtin to use the full terminal width.
Signed-off-by: Zbigniew Jędrzejewski-Szmek <zbyszek@in.waw.pl>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Maintaining an array of hashes is easier using sha1_array than
open-coding it. This patch also fixes a leak of the SHA1 array
in diff_tree_combined_merge().
Signed-off-by: René Scharfe <rene.scharfe@lsrfire.ath.cx>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Both of these free() calls are freeing a "const unsigned char (*)[20]"
type while free() expects a "void *". This results in the following
warning under clang 2.9:
builtin/diff.c:185:7: warning: passing 'const unsigned char (*)[20]' to parameter of type 'void *' discards qualifiers
free(parent);
^~~~~~
submodule.c:394:7: warning: passing 'const unsigned char (*)[20]' to parameter of type 'void *' discards qualifiers
free(parents);
^~~~~~~
This free()-ing without a cast was added by Jim Meyering to
builtin/diff.c in v1.7.6-rc3~4 and later by Fredrik Gustafsson in
submodule.c in v1.7.7-rc1~25^2.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
All of the "do we want color" flags default to -1 to
indicate that we don't have any color configured. This value
is handled in one of two ways:
1. In porcelain, we check early on whether the value is
still -1 after reading the config, and set it to the
value of color.ui (which defaults to 0).
2. In plumbing, it stays untouched as -1, and want_color
defaults it to off.
This works fine, but means that every porcelain has to check
and reassign its color flag. Now that want_color gives us a
place to put this check in a single spot, we can do that,
simplifying the calling code.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The return value from builtin_diff_files() is fed to diff_result_code()
by the caller, and all other callees like builtin_diff_index() do not
have their own call to diff_result_code(). Remove the duplicated one
from builtin_diff_files() and let the caller handle it.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When we had to refresh the index internally before running diff or status,
we opportunistically updated the $GIT_INDEX_FILE so that later invocation
of git can use the lstat(2) we already did in this invocation.
Make them share a helper function to do so.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"git diff --cached" (without revision) used to mean "git diff --cached
HEAD" (i.e. the user was too lazy to type HEAD). This "correctly"
failed when there was no commit yet. But was that correctness useful?
This patch changes the definition of what particular command means.
It is a request to show what _would_ be committed without further "git
add". The internal implementation is the same "git diff --cached HEAD"
when HEAD exists, but when there is no commit yet, it compares the index
with an empty tree object to achieve the desired result.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This was the only occurence of that usage, and square brackets are
sufficient and already well-established for that purpose.
Signed-off-by: Štěpán Němec <stepnem@gmail.com>
Acked-by: Sverre Rabbelier <srabbelier@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The .gitmodules file is parsed for "submodule.<name>.ignore" entries
before looking for them in .git/config. Thus settings found in .git/config
will override those from .gitmodules, thereby allowing the local developer
to ignore settings given by the remote side while also letting upstream
set defaults for those users who don't have special needs.
Signed-off-by: Jens Lehmann <Jens.Lehmann@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This shrinks the top-level directory a bit, and makes it much more
pleasant to use auto-completion on the thing. Instead of
[torvalds@nehalem git]$ em buil<tab>
Display all 180 possibilities? (y or n)
[torvalds@nehalem git]$ em builtin-sh
builtin-shortlog.c builtin-show-branch.c builtin-show-ref.c
builtin-shortlog.o builtin-show-branch.o builtin-show-ref.o
[torvalds@nehalem git]$ em builtin-shor<tab>
builtin-shortlog.c builtin-shortlog.o
[torvalds@nehalem git]$ em builtin-shortlog.c
you get
[torvalds@nehalem git]$ em buil<tab> [type]
builtin/ builtin.h
[torvalds@nehalem git]$ em builtin [auto-completes to]
[torvalds@nehalem git]$ em builtin/sh<tab> [type]
shortlog.c shortlog.o show-branch.c show-branch.o show-ref.c show-ref.o
[torvalds@nehalem git]$ em builtin/sho [auto-completes to]
[torvalds@nehalem git]$ em builtin/shor<tab> [type]
shortlog.c shortlog.o
[torvalds@nehalem git]$ em builtin/shortlog.c
which doesn't seem all that different, but not having that annoying
break in "Display all 180 possibilities?" is quite a relief.
NOTE! If you do this in a clean tree (no object files etc), or using an
editor that has auto-completion rules that ignores '*.o' files, you
won't see that annoying 'Display all 180 possibilities?' message - it
will just show the choices instead. I think bash has some cut-off
around 100 choices or something.
So the reason I see this is that I'm using an odd editory, and thus
don't have the rules to cut down on auto-completion. But you can
simulate that by using 'ls' instead, or something similar.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Change calls to die(..., strerror(errno)) to use the new die_errno().
In the process, also make slight style adjustments: at least state
_something_ about the function that failed (instead of just printing
the pathname), and put paths in single quotes.
Signed-off-by: Thomas Rast <trast@student.ethz.ch>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Right now for the diff porcelain and the log family, we
call:
init_revisions();
setup_revisions();
DIFF_OPT_SET(ALLOW_TEXTCONV);
However, that means textconv will _always_ be on, instead of
being a default that can be manipulated with
setup_revisions. Instead, we want:
init_revisions();
DIFF_OPT_SET(ALLOW_TEXTCONV);
setup_revisions();
which is what this patch does.
We'll go ahead and move the callsite in wt-status, also;
even though the user can't pass any options here, it is a
cleanup that will help avoid any surprise later if the
setup_revisions line is changed.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
According to the message of commit 0fe7c1de16,
"git diff" with three or more trees expects the merged tree first followed by
the parents, in order. However, this command reversed the order of its
arguments, resulting in confusing diffs. A comment /* Again, the revs are all
reverse */ suggested there was a reason for this, but I can't figure out the
reason, so I removed the reversal of the arguments. Test case included.
Signed-off-by: Matt McCutchen <matt@mattmccutchen.net>
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
The original intention of 72909be (Add diff-option --ext-diff, 2007-06-30)
was to optionally allow the use of external diff viewer in "git log"
family (while keeping them disabled by default). It exposed the "allow
external diff" bit to the UI, but forgot to adjust the "git diff" codepath
that was set up to always allow use of the external diff viewer.
Noticed by Nazri Ramliy; tests by René Scharfe squashed in.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This can do the lstat() storm in parallel, giving potentially much
improved performance for cold-cache cases or things like NFS that have
weak metadata caching.
Just use "read_cache_preload()" instead of "read_cache()" to force an
optimistic preload of the index stat data. The function takes a
pathspec as its argument, allowing us to preload only the relevant
portion of the index.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffs that have been produced with textconv almost certainly
cannot be applied, so we want to be careful not to generate
them in things like format-patch.
This introduces a new diff options, ALLOW_TEXTCONV, which
controls this behavior. It is off by default, but is
explicitly turned on for the "log" family of commands, as
well as the "diff" porcelain (but not diff-* plumbing).
Because both text conversion and external diffing are
controlled by these diff options, we can get rid of the
"plumbing versus porcelain" distinction when reading the
config. This was an attempt to control the same thing, but
suffered from being too coarse-grained.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
According to the message of commit 0fe7c1de16,
"git diff" with three or more trees expects the merged tree first followed by
the parents, in order. However, this command reversed the order of its
arguments, resulting in confusing diffs. A comment /* Again, the revs are all
reverse */ suggested there was a reason for this, but I can't figure out the
reason, so I removed the reversal of the arguments. Test case included.
Signed-off-by: Matt McCutchen <matt@mattmccutchen.net>
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Textual diff output for unmerged paths was too eager to give condensed
combined diff. Even though "diff -c" (and "diff-files -c -p") is a
request to view combined diff without condensing (otherwise the user would
have explicitly asked for --cc, not -c), we showed "--cc" output anyway.
0fe7c1d (built-in diff: assorted updates, 2006-04-29) claimed to be
careful about doing this, but its breakage was hidden because back then
"git diff" was still a shell script that did not use the codepath it
introduced fully.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
With a new configuration "diff.mnemonicprefix", "git diff" shows the
differences between various combinations of preimage and postimage trees
with prefixes different from the standard "a/" and "b/". Hopefully this
will make the distinction stand out for some people.
"git diff" compares the (i)ndex and the (w)ork tree;
"git diff HEAD" compares a (c)ommit and the (w)ork tree;
"git diff --cached" compares a (c)ommit and the (i)ndex;
"git-diff HEAD:file1 file2" compares an (o)bject and a (w)ork tree entity;
"git diff --no-index a b" compares two non-git things (1) and (2).
Because these mnemonics now have meanings, they are swapped when reverse
diff is in effect and this feature is enabled.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This fixes "git diff", "git diff-files" and "git diff-index" to work
correctly under worktree setup. Because diff* family works in many modes
and not all of them require worktree, Junio made a nice summary
(with a little modification from me):
* diff-files is about comparing with work tree, so it obviously needs a
work tree;
* diff-index also does, except "diff-index --cached" or "diff --cached TREE"
* no-index is about random files outside git context, so it obviously
doesn't need any work tree;
* comparing two (or more) trees doesn't;
* comparing two blobs doesn't;
* comparing a blob with a random file doesn't;
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
See for example, status and show commands. Besides,
Documentation/RelNotes-1.6.0.txt mentions that pager.<cmd>
can be used to enable/disable paging behavior per command.
Signed-off-by: Alex Riesen <raa.lkml@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When you misuse a git command, you are shown the usage string.
But this is currently shown in the dashed form. So if you just
copy what you see, it will not work, when the dashed form
is no longer supported.
This patch makes git commands show the dash-less version.
For shell scripts that do not specify OPTIONS_SPEC, git-sh-setup.sh
generates a dash-less usage string now.
Signed-off-by: Stephan Beyer <s-beyer@gmx.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Even if "foo" and/or "bar" does not exist in index, "git diff foo bar"
should not change behaviour drastically from "git diff foo bar baz" or
"git diff foo". A feature that "sometimes works and is handy" is an
unreliable cute hack.
"git diff foo bar" outside a git repository continues to work as a more
colourful alternative to "diff -u" as before.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
git_config() only had a function parameter, but no callback data
parameter. This assumes that all callback functions only modify
global variables.
With this patch, every callback gets a void * parameter, and it is hoped
that this will help the libification effort.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
setup_git_directory_gently() only modified the value of its *nongit_ok
argument if we were not in a git repository. Now it will always set it
to 0 when we are inside a repository.
Also remove now unnecessary initializations in the callers of this
function.
Signed-off-by: SZEDER Gábor <szeder@ira.uka.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This adds --relative option to the diff family. When you start
from a subdirectory:
$ git diff --relative
shows only the diff that is inside your current subdirectory,
and without $prefix part. People who usually live in
subdirectories may like it.
There are a few things I should also mention about the change:
- This works not just with diff but also works with the log
family of commands, but the history pruning is not affected.
In other words, if you go to a subdirectory, you can say:
$ git log --relative -p
but it will show the log message even for commits that do not
touch the current directory. You can limit it by giving
pathspec yourself:
$ git log --relative -p .
This originally was not a conscious design choice, but we
have a way to affect diff pathspec and pruning pathspec
independently. IOW "git log --full-diff -p ." tells it to
prune history to commits that affect the current subdirectory
but show the changes with full context. I think it makes
more sense to leave pruning independent from --relative than
the obvious alternative of always pruning with the current
subdirectory, which would break the symmetry.
- Because this works also with the log family, you could
format-patch a single change, limiting the effect to your
subdirectory, like so:
$ cd gitk-git
$ git format-patch -1 --relative 911f1eb
But because that is a special purpose usage, this option will
never become the default, with or without repository or user
preference configuration. The risk of producing a partial
patch and sending it out by mistake is too great if we did
so.
- This is inherently incompatible with --no-index, which is a
bolted-on hack that does not have much to do with git
itself. I didn't bother checking and erroring out on the
combined use of the options, but probably I should.
Signed-off-by: Junio 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: Junio 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: Wincent Colaiuta <win@wincent.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Instead of warning the user that it is expecting git log output from
the standard input (and waiting for the user to type the log from
the keyboard, which is a silly thing to do), default to traverse from
HEAD when there is no rev parameter given and the standard input is
a tty.
This factors out a useful helper "add_head()" from builtin-diff.c to a
more appropriate place revision.c while renaming it to more descriptive
name add_head_to_pending(), as that is what the function is about.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
reverse_diff was a bit-value in disguise, it's merged in the flags now.
Signed-off-by: Pierre Habouzit <madcoder@debian.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The point of the part of the code this patch touches is that if
we modified the active_cache, we try to write it out and make it
the index file for later users to use by calling
"commit_locked_index", but we do not really care about the
failure from this sequence because it is done purely as an
optimization.
The original code called three functions primarily for their
side effects but as condition of an if statement, which is
admittedly a bad style.
Incidentally, it squelches an "empty if body" warning from gcc.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The warning message to suggest "Consider running git-status" from
"git-diff" that we experimented with during the 1.5.3 cycle turns
out to be a bad idea. It robbed cache-dirty information from people
who valued it, while still asking users to run "update-index --refresh".
It was hoped that the new behaviour would at least have some educational
value, but not showing the cache-dirty paths like before meant that the
user would not even know easily which paths were cache-dirty, and it
made the need to refresh the index look like even more unnecessary chore.
This commit reinstates the traditional behaviour, but with a twist.
By default, the empty "diff --git" output is totally squelched out
from "git diff" output. At the end of the command, it automatically
runs "update-index --refresh" as needed, without even bothering the
user. In other words, people who do not care about the cache-dirtyness
do not even have to see the warning.
The traditional behaviour to see the stat-dirty output and to bypassing
the overhead of content comparison can be specified by setting the
configuration variable diff.autorefreshindex to false.
Signed-off-by: Junio 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: Junio C Hamano <gitster@pobox.com>
As Wincent Colaiuta found out, it's a bit unexpected for git diff to
start a pager even when the --quiet option is specified. The problem
is that the pager hides the return code -- which is the only output
we're interested in in this case.
Push pager setup down into builtin-diff.c and don't start the pager
if --exit-code or --quiet (which implies --exit-code) was specified.
Signed-off-by: Rene Scharfe <rene.scharfe@lsrfire.ath.cx>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The tree recursion behavior of git-diff may appear
inconsistent to the user because it depends on the format of
the patch as well as whether one is diffing between trees or
against the index.
Since git-diff is a porcelain wrapper for low-level diff
commands, it makes sense for its behavior to be consistent
no matter what is being diffed. This patch turns on
recursion in all cases.
Signed-off-by: Junio C Hamano <gitster@pobox.com>