The funcname patterns influence the "comment" on @@ lines of
the diff. They are safe to use with plumbing since they
don't fundamentally change the meaning of the diff in any
way.

Since all diff users call either diff_ui_config or
diff_basic_config, we can get rid of the lazy reading of the
config.
Signed-off-by: NJeff King <peff@peff.net>
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>

This moves the logic to quote two paths (prefix + path) in
C-style introduced in the previous commit from the
dump_quoted_path() in combine-diff.c to quote.c, and uses it to
fix rewrite_diff() that never C-quoted the pathnames correctly.
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>

We had the diff.external variable in the documentation of the config
file since its conception, but failed to respect it.
Signed-off-by: NJohannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

For consistency, make the two tools report whitespace errors in the
same way (the output of "diff --check" has been tweaked to match
that of "git apply").

Note that although the textual content is basically the same only
"git diff --check" provides a colorized version of the problematic
lines; making "git apply" do colorization will require more extensive
changes (figuring out the diff colorization preferences of the user)
and so that will be a subject for another commit.
Signed-off-by: NWincent Colaiuta <win@wincent.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

This commit unifies three separate places where whitespace checking was
performed:

 - the whitespace checking previously done in builtin-apply.c is
extracted into a function in ws.c

 - the equivalent logic in "git diff" is removed

 - the emit_line_with_ws() function is also removed because that also
rechecks the whitespace, and its functionality is rolled into ws.c

The new function is called check_and_emit_line() and it does two things:
checks a line for whitespace errors and optionally emits it. The checking
is based on lines of content rather than patch lines (in other words, the
caller must strip the leading "+" or "-"); this was suggested by Junio on
the mailing list to allow for a future extension to "git show" to display
whitespace errors in blobs.

At the same time we teach it to report all classes of whitespace errors
found for a given line rather than reporting only the first found error.
Signed-off-by: NWincent Colaiuta <win@wincent.com>
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>

This inserts a new function xdi_diff() that currently does not
do anything other than calling the underlying xdl_diff() to the
callchain of current callers of xdl_diff() function.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

"diff --check" would only detect spaces before tabs if a tab was the
last character in the leading indent. Fix that and add a test case to
make sure the bug doesn't regress in the future.
Signed-off-by: NWincent Colaiuta <win@wincent.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

The "-z" format is all about machine parsability, but showing renamed
paths as "common/{a => b}/suffix" makes it impossible.  The scripts would
never have successfully parsed "--numstat -z -M" in the old format.

This fixes the output format in a (hopefully minimally) backward
incompatible way.

 * The output without -z is not changed.  This has given a good way for
   humans to view added and deleted lines separately, and showing the
   path in combined, shorter way would preserve readability.

 * The output with -z is unchanged for paths that do not involve renames.
   Existing scripts that do not pass -M/-C are not affected at all.

 * The output with -z for a renamed path is shown in a format that can
   easily be distinguished from an unrenamed path.

This is based on Jakub Narebski's patch.  Bugs and documentation typos
are mine.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

For consistency, change "white space" and "whitespaces" to
"whitespace", fixing a couple of adjacent grammar problems in the
docs.
Signed-off-by: NWincent Colaiuta <win@wincent.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

The `core.whitespace` configuration variable allows you to define what
`diff` and `apply` should consider whitespace errors for all paths in
the project (See gitlink:git-config[1]).  This attribute gives you finer
control per path.

For example, if you have these in the .gitattributes:

    frotz   whitespace
    nitfol  -whitespace
    xyzzy   whitespace=-trailing

all types of whitespace problems known to git are noticed in path 'frotz'
(i.e. diff shows them in diff.whitespace color, and apply warns about
them), no whitespace problem is noticed in path 'nitfol', and the
default types of whitespace problems except "trailing whitespace" are
noticed for path 'xyzzy'.  A project with mixed Python and C might want
to have:

    *.c    whitespace
    *.py   whitespace=-indent-with-non-tab

in its toplevel .gitattributes file.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

This adds an option to help scripts find out color settings from
the configuration file.

    git config --get-colorbool color.diff

inspects color.diff variable, and exits with status 0 (i.e. success) if
color is to be used.  It exits with status 1 otherwise.

If a script wants "true"/"false" answer to the standard output of the
command, it can pass an additional boolean parameter to its command
line, telling if its standard output is a terminal, like this:

    git config --get-colorbool color.diff true

When called like this, the command outputs "true" to its standard output
if color is to be used (i.e. "color.diff" says "always", "auto", or
"true"), and "false" otherwise.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

663af342 (Full rework of
quote_c_style and write_name_quoted.) mistakenly used puts()
when writing out a fixed string when it did not want to add a
terminating LF.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

This is a line reordering patch _only_.
Signed-off-by: NPierre Habouzit <madcoder@debian.org>
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>

This introduces a new whitespace error type, "indent-with-non-tab".
The error is about starting a line with 8 or more SP, instead of
indenting it with a HT.

This is not enabled by default, as some projects employ an
indenting policy to use only SPs and no HTs.

The kernel folks and git contributors may want to enable this
detection with:

	[core]
		whitespace = indent-with-non-tab
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

This introduces core.whitespace configuration variable that lets
you specify the definition of "whitespace error".

Currently there are two kinds of whitespace errors defined:

 * trailing-space: trailing whitespaces at the end of the line.

 * space-before-tab: a SP appears immediately before HT in the
   indent part of the line.

You can specify the desired types of errors to be detected by
listing their names (unique abbreviations are accepted)
separated by comma.  By default, these two errors are always
detected, as that is the traditional behaviour.  You can disable
detection of a particular type of error by prefixing a '-' in
front of the name of the error, like this:

	[core]
		whitespace = -trailing-space

This patch teaches the code to output colored diff with
DIFF_WHITESPACE color to highlight the detected whitespace
errors to honor the new configuration.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

The core rename detection had some rather stupid code to check if a
pathname was used by a later modification or rename, which basically
walked the whole pathname space for all renames for each rename, in
order to tell whether it was a pure rename (no remaining users) or
should be considered a copy (other users of the source file remaining).

That's really silly, since we can just keep a count of users around, and
replace all those complex and expensive loops with just testing that
simple counter (but this all depends on the previous commit that shared
the diff_filespec data structure by using a separate reference count).

Note that the reference count is not the same as the rename count: they
behave otherwise rather similarly, but the reference count is tied to
the allocation (and decremented at de-allocation, so that when it turns
zero we can get rid of the memory), while the rename count is tied to
the renames and is decremented when we find a rename (so that when it
turns zero we know that it was a rename, not a copy).
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Rather than copy the filespecs when introducing new versions of them
(for rename or copy detection), use a refcount and increment the count
when reusing the diff_filespec.

This avoids unnecessary allocations, but the real reason behind this is
a future enhancement: we will want to track shared data across the
copy/rename detection.  In order to efficiently notice when a filespec
is used by a rename, the rename machinery wants to keep track of a
rename usage count which is shared across all different users of the
filespec.
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Fix size_t vs. unsigned long pointer mismatch warnings introduced
with the addition of strbuf_detach().
Signed-off-by: NRene Scharfe <rene.scharfe@lsrfire.ath.cx>
Signed-off-by: NShawn O. Pearce <spearce@spearce.org>

Signed-off-by: NJohannes Sixt <johannes.sixt@telecom.at>
Signed-off-by: NShawn O. Pearce <spearce@spearce.org>

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

We find rename candidates by computing a fingerprint hash of
each file, and then comparing those fingerprints. There are
inherently O(n^2) comparisons, so it pays in CPU time to
hoist the (rather expensive) computation of the fingerprint
out of that loop (or to cache it once we have computed it once).

Previously, we didn't keep the filespec information around
because then we had the potential to consume a great deal of
memory. However, instead of keeping all of the filespec
data, we can instead just keep the fingerprint.

This patch implements and uses diff_free_filespec_data_large
to accomplish that goal. We also have to change
estimate_similarity not to needlessly repopulate the
filespec data when we already have the hash.

Practical tests showed 4.5x speedup for a 10% memory usage
increase.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

For that purpose, the ->buf is always initialized with a char * buf living
in the strbuf module. It is made a char * so that we can sloppily accept
things that perform: sb->buf[0] = '\0', and because you can't pass "" as an
initializer for ->buf without making gcc unhappy for very good reasons.

strbuf_init/_detach/_grow have been fixed to trust ->alloc and not ->buf
anymore.

as a consequence strbuf_detach is _mandatory_ to detach a buffer, copying
->buf isn't an option anymore, if ->buf is going to escape from the scope,
and eventually be free'd.

API changes:
  * strbuf_setlen now always works, so just make strbuf_reset a convenience
    macro.
  * strbuf_detatch takes a size_t* optional argument (meaning it can be
    NULL) to copy the buffer's len, as it was needed for this refactor to
    make the code more readable, and working like the callers.
Signed-off-by: NPierre Habouzit <madcoder@debian.org>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

We find rename candidates by computing a fingerprint hash of
each file, and then comparing those fingerprints. There are
inherently O(n^2) comparisons, so it pays in CPU time to
hoist the (rather expensive) computation of the fingerprint
out of that loop (or to cache it once we have computed it once).

Previously, we didn't keep the filespec information around
because then we had the potential to consume a great deal of
memory. However, instead of keeping all of the filespec
data, we can instead just keep the fingerprint.

This patch implements and uses diff_free_filespec_data_large
to accomplish that goal. We also have to change
estimate_similarity not to needlessly repopulate the
filespec data when we already have the hash.

Practical tests showed 4.5x speedup for a 10% memory usage
increase.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

* quote_c_style works on a strbuf instead of a wild buffer.
* quote_c_style is now clever enough to not add double quotes if not needed.

* write_name_quoted inherits those advantages, but also take a different
  set of arguments. Now instead of asking for quotes or not, you pass a
  "terminator". If it's \0 then we assume you don't want to escape, else C
  escaping is performed. In any case, the terminator is also appended to the
  stream. It also no longer takes the prefix/prefix_len arguments, as it's
  seldomly used, and makes some optimizations harder.

* write_name_quotedpfx is created to work like write_name_quoted and take
  the prefix/prefix_len arguments.

Thanks to those API changes, diff.c has somehow lost weight, thanks to the
removal of functions that were wrappers around the old write_name_quoted
trying to give it a semantics like the new one, but performing a lot of
allocations for this goal. Now we always write directly to the stream, no
intermediate allocation is performed.

As a side effect of the refactor in builtin-apply.c, the length of the bar
graphs in diffstats are not affected anymore by the fact that the path was
clipped.
Signed-off-by: NPierre Habouzit <madcoder@debian.org>

Signed-off-by: NPierre Habouzit <madcoder@debian.org>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Signed-off-by: NPierre Habouzit <madcoder@debian.org>
Acked-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

* Now, those functions take an "out" strbuf argument, where they store their
  result if any. In that case, it also returns 1, else it returns 0.
* those functions support "in place" editing, in the sense that it's OK to
  call them this way:
    convert_to_git(path, sb->buf, sb->len, sb);
  When doable, conversions are done in place for real, else the strbuf
  content is just replaced with the new one, transparentely for the caller.

If you want to create a new filter working this way, being the accumulation
of filter1, filter2, ... filtern, then your meta_filter would be:

    int meta_filter(..., const char *src, size_t len, struct strbuf *sb)
    {
        int ret = 0;
        ret |= filter1(...., src, len, sb);
        if (ret) {
            src = sb->buf;
            len = sb->len;
        }
        ret |= filter2(...., src, len, sb);
        if (ret) {
            src = sb->buf;
            len = sb->len;
        }
        ....
        return ret | filtern(..., src, len, sb);
    }

That's why subfilters the convert_to_* functions called were also rewritten
to work this way.
Signed-off-by: NPierre Habouzit <madcoder@debian.org>
Acked-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

This adds more proper rename detection limits. Instead of just checking
the limit against the number of potential rename destinations, we verify
that the rename matrix (which is what really matters) doesn't grow
ridiculously large, and we also make sure that we don't overflow when
doing the matrix size calculation.

This also changes the default limits from unlimited, to a rename matrix
that is limited to 100 entries on a side. You can raise it with the config
entry, or by using the "-l<n>" command line flag, but at least the default
is now a sane number that avoids spending lots of time (and memory) in
situations that likely don't merit it.

The choice of default value is of course very debatable. Limiting the
rename matrix to a 100x100 size will mean that even if you have just one
obvious rename, but you also create (or delete) 10,000 files, the rename
matrix will be so big that we disable the heuristics. Sounds reasonable to
me, but let's see if people hit this (and, perhaps more importantly,
actually *care*) in real life.
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

  * Add strbuf_rtrim to remove trailing spaces.
  * Add strbuf_insert to insert data at a given position.
  * Off-by one fix in strbuf_addf: strbuf_avail() does not counts the final
    \0 so the overflow test for snprintf is the strict comparison. This is
    not critical as the growth mechanism chosen will always allocate _more_
    memory than asked, so the second test will not fail. It's some kind of
    miracle though.
  * Add size extension hints for strbuf_init and strbuf_read. If 0, default
    applies, else:
      + initial buffer has the given size for strbuf_init.
      + first growth checks it has at least this size rather than the
        default 8192.
Signed-off-by: NPierre Habouzit <madcoder@debian.org>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

The code to squelch empty diffs introduced by commit
fb13227e would inadvertently
populate filespec "two" of a submodule change using the uninitialized
(null) SHA1, thereby replacing the submodule SHA1 by 0{40} in the output.

This change teaches diffcore_skip_stat_unmatch to handle
submodule changes correctly.
Signed-off-by: NSven Verdoolaege <skimo@kotnet.org>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Signed-off-by: NPierre Habouzit <madcoder@debian.org>
Signed-off-by: NJunio 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: NJunio C Hamano <gitster@pobox.com>

We used to not generate a patch ID for binary diffs, but that means that
some commits may be skipped as being identical to already-applied diffs
when doing a rebase.

So just delete the code that skips the binary diff. At the very least,
we'd want the filenames to be part of the patch ID, but we might also want
to generate some hash for the binary diff itself too.

This fixes an issue noticed by Torgil Svensson.
Tested-by: NTorgil Svensson <torgil.svensson@gmail.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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>