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Author SHA1 Message Date
Junio C Hamano
8eaf517835 Merge branch 'ks/tree-diff-nway'
Instead of running N pair-wise diff-trees when inspecting a
N-parent merge, find the set of paths that were touched by walking
N+1 trees in parallel.  These set of paths can then be turned into
N pair-wise diff-tree results to be processed through rename
detections and such.  And N=2 case nicely degenerates to the usual
2-way diff-tree, which is very nice.

* ks/tree-diff-nway:
  mingw: activate alloca
  combine-diff: speed it up, by using multiparent diff tree-walker directly
  tree-diff: rework diff_tree() to generate diffs for multiparent cases as well
  Portable alloca for Git
  tree-diff: reuse base str(buf) memory on sub-tree recursion
  tree-diff: no need to call "full" diff_tree_sha1 from show_path()
  tree-diff: rework diff_tree interface to be sha1 based
  tree-diff: diff_tree() should now be static
  tree-diff: remove special-case diff-emitting code for empty-tree cases
  tree-diff: simplify tree_entry_pathcmp
  tree-diff: show_path prototype is not needed anymore
  tree-diff: rename compare_tree_entry -> tree_entry_pathcmp
  tree-diff: move all action-taking code out of compare_tree_entry()
  tree-diff: don't assume compare_tree_entry() returns -1,0,1
  tree-diff: consolidate code for emitting diffs and recursion in one place
  tree-diff: show_tree() is not needed
  tree-diff: no need to pass match to skip_uninteresting()
  tree-diff: no need to manually verify that there is no mode change for a path
  combine-diff: move changed-paths scanning logic into its own function
  combine-diff: move show_log_first logic/action out of paths scanning
2014-06-03 12:06:40 -07:00
Kirill Smelkov
72441af7c4 tree-diff: rework diff_tree() to generate diffs for multiparent cases as well
Previously diff_tree(), which is now named ll_diff_tree_sha1(), was
generating diff_filepair(s) for two trees t1 and t2, and that was
usually used for a commit as t1=HEAD~, and t2=HEAD - i.e. to see changes
a commit introduces.

In Git, however, we have fundamentally built flexibility in that a
commit can have many parents - 1 for a plain commit, 2 for a simple merge,
but also more than 2 for merging several heads at once.

For merges there is a so called combine-diff, which shows diff, a merge
introduces by itself, omitting changes done by any parent. That works
through first finding paths, that are different to all parents, and then
showing generalized diff, with separate columns for +/- for each parent.
The code lives in combine-diff.c .

There is an impedance mismatch, however, in that a commit could
generally have any number of parents, and that while diffing trees, we
divide cases for 2-tree diffs and more-than-2-tree diffs. I mean there
is no special casing for multiple parents commits in e.g.
revision-walker .

That impedance mismatch *hurts* *performance* *badly* for generating
combined diffs - in "combine-diff: optimize combine_diff_path
sets intersection" I've already removed some slowness from it, but from
the timings provided there, it could be seen, that combined diffs still
cost more than an order of magnitude more cpu time, compared to diff for
usual commits, and that would only be an optimistic estimate, if we take
into account that for e.g. linux.git there is only one merge for several
dozens of plain commits.

That slowness comes from the fact that currently, while generating
combined diff, a lot of time is spent computing diff(commit,commit^2)
just to only then intersect that huge diff to almost small set of files
from diff(commit,commit^1).

That's because at present, to compute combine-diff, for first finding
paths, that "every parent touches", we use the following combine-diff
property/definition:

D(A,P1...Pn) = D(A,P1) ^ ... ^ D(A,Pn)      (w.r.t. paths)

where

D(A,P1...Pn) is combined diff between commit A, and parents Pi

and

D(A,Pi) is usual two-tree diff Pi..A

So if any of that D(A,Pi) is huge, tracting 1 n-parent combine-diff as n
1-parent diffs and intersecting results will be slow.

And usually, for linux.git and other topic-based workflows, that
D(A,P2) is huge, because, if merge-base of A and P2, is several dozens
of merges (from A, via first parent) below, that D(A,P2) will be diffing
sum of merges from several subsystems to 1 subsystem.

The solution is to avoid computing n 1-parent diffs, and to find
changed-to-all-parents paths via scanning A's and all Pi's trees
simultaneously, at each step comparing their entries, and based on that
comparison, populate paths result, and deduce we could *skip*
*recursing* into subdirectories, if at least for 1 parent, sha1 of that
dir tree is the same as in A. That would save us from doing significant
amount of needless work.

Such approach is very similar to what diff_tree() does, only there we
deal with scanning only 2 trees simultaneously, and for n+1 tree, the
logic is a bit more complex:

D(T,P1...Pn) calculation scheme
-------------------------------

D(T,P1...Pn) = D(T,P1) ^ ... ^ D(T,Pn)	(regarding resulting paths set)

    D(T,Pj)		- diff between T..Pj
    D(T,P1...Pn)	- combined diff from T to parents P1,...,Pn

We start from all trees, which are sorted, and compare their entries in
lock-step:

     T     P1       Pn
     -     -        -
    |t|   |p1|     |pn|
    |-|   |--| ... |--|      imin = argmin(p1...pn)
    | |   |  |     |  |
    |-|   |--|     |--|
    |.|   |. |     |. |
     .     .        .
     .     .        .

at any time there could be 3 cases:

    1)  t < p[imin];
    2)  t > p[imin];
    3)  t = p[imin].

Schematic deduction of what every case means, and what to do, follows:

1)  t < p[imin]  ->  ∀j t ∉ Pj  ->  "+t" ∈ D(T,Pj)  ->  D += "+t";  t↓

2)  t > p[imin]

    2.1) ∃j: pj > p[imin]  ->  "-p[imin]" ∉ D(T,Pj)  ->  D += ø;  ∀ pi=p[imin]  pi↓
    2.2) ∀i  pi = p[imin]  ->  pi ∉ T  ->  "-pi" ∈ D(T,Pi)  ->  D += "-p[imin]";  ∀i pi↓

3)  t = p[imin]

    3.1) ∃j: pj > p[imin]  ->  "+t" ∈ D(T,Pj)  ->  only pi=p[imin] remains to investigate
    3.2) pi = p[imin]  ->  investigate δ(t,pi)
     |
     |
     v

    3.1+3.2) looking at δ(t,pi) ∀i: pi=p[imin] - if all != ø  ->

                      ⎧δ(t,pi)  - if pi=p[imin]
             ->  D += ⎨
                      ⎩"+t"     - if pi>p[imin]

    in any case t↓  ∀ pi=p[imin]  pi↓

~

For comparison, here is how diff_tree() works:

D(A,B) calculation scheme
-------------------------

    A     B
    -     -
   |a|   |b|    a < b   ->  a ∉ B   ->   D(A,B) +=  +a    a↓
   |-|   |-|    a > b   ->  b ∉ A   ->   D(A,B) +=  -b    b↓
   | |   | |    a = b   ->  investigate δ(a,b)            a↓ b↓
   |-|   |-|
   |.|   |.|
    .     .
    .     .

~~~~~~~~

This patch generalizes diff tree-walker to work with arbitrary number of
parents as described above - i.e. now there is a resulting tree t, and
some parents trees tp[i] i=[0..nparent). The generalization builds on
the fact that usual diff

D(A,B)

is by definition the same as combined diff

D(A,[B]),

so if we could rework the code for common case and make it be not slower
for nparent=1 case, usual diff(t1,t2) generation will not be slower, and
multiparent diff tree-walker would greatly benefit generating
combine-diff.

What we do is as follows:

1) diff tree-walker ll_diff_tree_sha1() is internally reworked to be
   a paths generator (new name diff_tree_paths()), with each generated path
   being `struct combine_diff_path` with info for path, new sha1,mode and for
   every parent which sha1,mode it was in it.

2) From that info, we can still generate usual diff queue with
   struct diff_filepairs, via "exporting" generated
   combine_diff_path, if we know we run for nparent=1 case.
   (see emit_diff() which is now named emit_diff_first_parent_only())

3) In order for diff_can_quit_early(), which checks

       DIFF_OPT_TST(opt, HAS_CHANGES))

   to work, that exporting have to be happening not in bulk, but
   incrementally, one diff path at a time.

   For such consumers, there is a new callback in diff_options
   introduced:

       ->pathchange(opt, struct combine_diff_path *)

   which, if set to !NULL, is called for every generated path.

   (see new compat ll_diff_tree_sha1() wrapper around new paths
    generator for setup)

4) The paths generation itself, is reworked from previous
   ll_diff_tree_sha1() code according to "D(A,P1...Pn) calculation
   scheme" provided above:

   On the start we allocate [nparent] arrays in place what was
   earlier just for one parent tree.

   then we just generalize loops, and comparison according to the
   algorithm.

Some notes(*):

1) alloca(), for small arrays, is used for "runs not slower for
   nparent=1 case than before" goal - if we change it to xmalloc()/free()
   the timings get ~1% worse. For alloca() we use just-introduced
   xalloca/xalloca_free compatibility wrappers, so it should not be a
   portability problem.

2) For every parent tree, we need to keep a tag, whether entry from that
   parent equals to entry from minimal parent. For performance reasons I'm
   keeping that tag in entry's mode field in unused bit - see S_IFXMIN_NEQ.
   Not doing so, we'd need to alloca another [nparent] array, which hurts
   performance.

3) For emitted paths, memory could be reused, if we know the path was
   processed via callback and will not be needed later. We use efficient
   hand-made realloc-style path_appendnew(), that saves us from ~1-1.5%
   of potential additional slowdown.

4) goto(s) are used in several places, as the code executes a little bit
   faster with lowered register pressure.

Also

- we should now check for FIND_COPIES_HARDER not only when two entries
  names are the same, and their hashes are equal, but also for a case,
  when a path was removed from some of all parents having it.

  The reason is, if we don't, that path won't be emitted at all (see
  "a > xi" case), and we'll just skip it, and FIND_COPIES_HARDER wants
  all paths - with diff or without - to be emitted, to be later analyzed
  for being copies sources.

  The new check is only necessary for nparent >1, as for nparent=1 case
  xmin_eqtotal always =1 =nparent, and a path is always added to diff as
  removal.

~~~~~~~~

Timings for

    # without -c, i.e. testing only nparent=1 case
    `git log --raw --no-abbrev --no-renames`

before and after the patch are as follows:

                navy.git        linux.git v3.10..v3.11

    before      0.611s          1.889s
    after       0.619s          1.907s
    slowdown    1.3%            0.9%

This timings show we did no harm to usual diff(tree1,tree2) generation.
From the table we can see that we actually did ~1% slowdown, but I think
I've "earned" that 1% in the previous patch ("tree-diff: reuse base
str(buf) memory on sub-tree recursion", HEAD~~) so for nparent=1 case,
net timings stays approximately the same.

The output also stayed the same.

(*) If we revert 1)-4) to more usual techniques, for nparent=1 case,
    we'll get ~2-2.5% of additional slowdown, which I've tried to avoid, as
   "do no harm for nparent=1 case" rule.

For linux.git, combined diff will run an order of magnitude faster and
appropriate timings will be provided in the next commit, as we'll be
taking advantage of the new diff tree-walker for combined-diff
generation there.

P.S. and combined diff is not some exotic/for-play-only stuff - for
example for a program I write to represent Git archives as readonly
filesystem, there is initial scan with

    `git log --reverse --raw --no-abbrev --no-renames -c`

to extract log of what was created/changed when, as a result building a
map

    {}  sha1    ->  in which commit (and date) a content was added

that `-c` means also show combined diff for merges, and without them, if
a merge is non-trivial (merges changes from two parents with both having
separate changes to a file), or an evil one, the map will not be full,
i.e. some valid sha1 would be absent from it.

That case was my initial motivation for combined diffs speedup.

Signed-off-by: Kirill Smelkov <kirr@mns.spb.ru>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-04-07 14:40:46 -07:00
Kirill Smelkov
ad6f3cc7d2 tree-diff: diff_tree() should now be static
We reworked all its users to use the functionality through
diff_tree_sha1 variant in recent patches (see "tree-diff: allow
diff_tree_sha1 to accept NULL sha1" and what comes next).

diff_tree() is now not used outside tree-diff.c - make it static.

Signed-off-by: Kirill Smelkov <kirr@mns.spb.ru>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-03-26 14:30:47 -07:00
Junio C Hamano
2687ffdeb7 Merge branch 'jc/hold-diff-remove-q-synonym-for-no-deletion'
Remove a confusing and deprecated "-q" option from "git diff-files";
"git diff-files --diff-filter=d" can be used instead.
2014-03-07 15:17:41 -08:00
Kirill Smelkov
af82c7880f combine-diff: combine_diff_path.len is not needed anymore
The field was used in order to speed-up name comparison and also to
mark removed paths by setting it to 0.

Because the updated code does significantly less strcmp and also
just removes paths from the list and free right after we know a path
will not be needed, it is not needed anymore.

Signed-off-by: Kirill Smelkov <kirr@mns.spb.ru>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-02-24 14:44:57 -08:00
Junio C Hamano
73b063130b Merge branch 'tg/diff-no-index-refactor'
"git diff ../else/where/A ../else/where/B" when ../else/where is
clearly outside the repository, and "git diff --no-index A B", do
not have to look at the index at all, but we used to read the index
unconditionally.

* tg/diff-no-index-refactor:
  diff: avoid some nesting
  diff: add test for --no-index executed outside repo
  diff: don't read index when --no-index is given
  diff: move no-index detection to builtin/diff.c
2013-12-27 14:58:17 -08:00
Junio C Hamano
6904f9aa5b Merge branch 'zk/difftool-counts'
Show the total number of paths and the number of paths shown so far
when "git difftool" prompts to launch an external diff tool, which
would give users some sense of progress.

* zk/difftool-counts:
  diff.c: fix some recent whitespace style violations
  difftool: display the number of files in the diff queue in the prompt
2013-12-27 14:58:13 -08:00
Thomas Gummerer
470faf9654 diff: move no-index detection to builtin/diff.c
Currently the --no-index option is parsed in diff_no_index().  Move the
detection if a no-index diff should be executed to builtin/diff.c, where
we can use it for executing diff_no_index() conditionally.  This will
also allow us to execute other operations conditionally, which will be
done in the next patch.

There are no functional changes.

Helped-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Thomas Gummerer <t.gummerer@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-12-12 12:23:02 -08:00
Zoltan Klinger
ee7fb0b1d4 difftool: display the number of files in the diff queue in the prompt
When --prompt option is set, git-difftool displays a prompt for each
modified file to be viewed in an external diff program.  At that
point, it could be useful to display a counter and the total number
of files in the diff queue.

Below is the current difftool prompt for the first of 5 modified files:

    Viewing: 'diff.c'
    Launch 'vimdiff' [Y/n]:

Consider the modified prompt:

    Viewing (1/5): 'diff.c'
    Launch 'vimdiff' [Y/n]:

The current GIT_EXTERNAL_DIFF mechanism does not tell the number of
paths in the diff queue nor the current counter.  To make this
"counter/total" info available for GIT_EXTERNAL_DIFF programs
without breaking existing ones by doing the following:

 - Keep track of the number of paths shown so far in diff_options;

 - Export two new environment variables from run_external_diff() to
   show the total number of paths (from diff_queue_struct) and the
   current value of the counter (from diff_options); and

 - Update git-difftool--helper to use these two environment variables.

Signed-off-by: Zoltan Klinger <zoltan.klinger@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-12-06 14:00:27 -08:00
Nicolas Vigier
b0d12fc9b2 Use the word 'stuck' instead of 'sticked'
The past participle of 'stick' is 'stuck'.

Signed-off-by: Nicolas Vigier <boklm@mars-attacks.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-10-31 15:47:38 -07:00
Junio C Hamano
4197361e39 Merge branch 'mg/more-textconv'
Make "git grep" and "git show" pay attention to --textconv when
dealing with blob objects.

* mg/more-textconv:
  grep: honor --textconv for the case rev:path
  grep: allow to use textconv filters
  t7008: demonstrate behavior of grep with textconv
  cat-file: do not die on --textconv without textconv filters
  show: honor --textconv for blobs
  diff_opt: track whether flags have been set explicitly
  t4030: demonstrate behavior of show with textconv
2013-10-23 13:21:31 -07:00
Junio C Hamano
b02f5aeda6 Merge branch 'jl/submodule-mv'
"git mv A B" when moving a submodule A does "the right thing",
inclusing relocating its working tree and adjusting the paths in
the .gitmodules file.

* jl/submodule-mv: (53 commits)
  rm: delete .gitmodules entry of submodules removed from the work tree
  mv: update the path entry in .gitmodules for moved submodules
  submodule.c: add .gitmodules staging helper functions
  mv: move submodules using a gitfile
  mv: move submodules together with their work trees
  rm: do not set a variable twice without intermediate reading.
  t6131 - skip tests if on case-insensitive file system
  parse_pathspec: accept :(icase)path syntax
  pathspec: support :(glob) syntax
  pathspec: make --literal-pathspecs disable pathspec magic
  pathspec: support :(literal) syntax for noglob pathspec
  kill limit_pathspec_to_literal() as it's only used by parse_pathspec()
  parse_pathspec: preserve prefix length via PATHSPEC_PREFIX_ORIGIN
  parse_pathspec: make sure the prefix part is wildcard-free
  rename field "raw" to "_raw" in struct pathspec
  tree-diff: remove the use of pathspec's raw[] in follow-rename codepath
  remove match_pathspec() in favor of match_pathspec_depth()
  remove init_pathspec() in favor of parse_pathspec()
  remove diff_tree_{setup,release}_paths
  convert common_prefix() to use struct pathspec
  ...
2013-09-09 14:36:15 -07:00
Junio C Hamano
c48f6816f0 diff: remove "diff-files -q" in a version of Git in a distant future
This was inherited from "show-diff -q" that was invented to tell
comparison between the index and the working tree to ignore only
removals in 2005.

These days, it is spelled as "--diff-filter=d".

Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-07-19 15:22:29 -07:00
Junio C Hamano
95a7c546b0 diff: deprecate -q option to diff-files
This reimplements the ancient "-q" option to "git diff-files" that
was inherited from "show-diff -q" in terms of "--diff-filter=d".  We
will be deprecating the "-q" option, so let's issue a warning when
we do so.

Incidentally this also tentatively fixes "git diff --no-index" to
honor "-q" and hide deletions; the use will get the same warning.

We should remove the support for "-q" in a future version but it is
not that urgent.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-07-19 15:20:47 -07:00
Junio C Hamano
1ecc1cbd3a diff: preparse --diff-filter string argument
Instead of running strchr() on the list of status characters over
and over again, parse the --diff-filter option into bitfields and
use the bits to see if the change to the filepair matches the status
requested.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-07-17 16:23:34 -07:00
Nguyễn Thái Ngọc Duy
bd1928df1d remove diff_tree_{setup,release}_paths
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-07-15 10:56:09 -07:00
Nguyễn Thái Ngọc Duy
64acde94ef move struct pathspec and related functions to pathspec.[ch]
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-07-15 10:56:06 -07:00
Junio C Hamano
6c374008b1 diff_opt: track whether flags have been set explicitly
The diff_opt infrastructure sets flags based on defaults and command
line options.  It is impossible to tell whether a flag has been set
as a default or on explicit request.  Update the structure so that
this detection is possible:

 * Add an extra "opt->touched_flags" that keeps track of all the
   fields that have been touched by DIFF_OPT_SET and DIFF_OPT_CLR.

 * You may continue setting the default values to the flags, like
   commands in the "log" family do in cmd_log_init_defaults(), but
   after you finished setting the defaults, you clear the
   touched_flags field;

 * And then you let the usual callchain call diff_opt_parse(),
   allowing the opt->flags be set or unset, while keeping track of
   which bits the user touched;

 * There is an optional callback "opt->set_default" that is called
   at the very beginning to let you inspect touched_flags and update
   opt->flags appropriately, before the remainder of the diffcore
   machinery is set up, taking the opt->flags value into account.

Signed-off-by: Michael J Gruber <git@drmicha.warpmail.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-05-10 10:24:17 -07:00
Junio C Hamano
abea4dc76a Merge branch 'mp/diff-algo-config'
Add diff.algorithm configuration so that the user does not type
"diff --histogram".

* mp/diff-algo-config:
  diff: Introduce --diff-algorithm command line option
  config: Introduce diff.algorithm variable
  git-completion.bash: Autocomplete --minimal and --histogram for git-diff
2013-02-17 15:25:52 -08:00
John Keeping
f192223447 diff: add diff_line_prefix function
This is a helper function to call the diff output_prefix function and
return its value as a C string, allowing us to greatly simplify
everywhere that needs to get the output prefix.

Signed-off-by: John Keeping <john@keeping.me.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-02-12 11:42:07 -08:00
Michal Privoznik
07924d4d50 diff: Introduce --diff-algorithm command line option
Since command line options have higher priority than config file
variables and taking previous commit into account, we need a way
how to specify myers algorithm on command line. However,
inventing `--myers` is not the right answer. We need far more
general option, and that is `--diff-algorithm`.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-01-16 09:41:18 -08:00
Nguyễn Thái Ngọc Duy
4914c9629c Move setup_diff_pager to libgit.a
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>
2012-10-29 03:08:30 -04:00
Junio C Hamano
d2aea1371b diff.c: mark a private file-scope symbol as static
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2012-09-15 22:58:20 -07:00
Junio C Hamano
3b753148b6 Merge branch 'jk/maint-null-in-trees'
We do not want a link to 0{40} object stored anywhere in our objects.

* jk/maint-null-in-trees:
  fsck: detect null sha1 in tree entries
  do not write null sha1s to on-disk index
  diff: do not use null sha1 as a sentinel value
2012-08-27 11:54:28 -07:00
Junio C Hamano
9cd33bbc52 Merge branch 'tr/void-diff-setup-done'
Remove unnecessary code.

* tr/void-diff-setup-done:
  diff_setup_done(): return void
2012-08-22 11:52:27 -07:00
Thomas Rast
28452655af diff_setup_done(): return void
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>
2012-08-03 12:11:07 -07:00
Jeff King
e54501004a diff: do not use null sha1 as a sentinel value
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>
2012-07-29 15:04:32 -07:00
Junio C Hamano
73ff8cf784 Merge branch 'lp/diffstat-with-graph'
"log --graph" was not very friendly with "--stat" option and its output
had line breaks at wrong places.

By Lucian Poston (5) and Zbigniew Jędrzejewski-Szmek (2)
* lp/diffstat-with-graph:
  t4052: work around shells unable to set COLUMNS to 1
  Prevent graph_width of stat width from falling below min
  t4052: Test diff-stat output with minimum columns
  t4052: Adjust --graph --stat output for prefixes
  Adjust stat width calculations to take --graph output into account
  Add output_prefix_length to diff_options
  t4052: test --stat output with --graph
2012-05-02 13:51:59 -07:00
Junio C Hamano
c0599f6993 Merge branch 'jk/diff-no-rename-empty'
Forbids rename detection logic from matching two empty files as renames
during merge-recursive to prevent mismerges.

By Jeff King
* jk/diff-no-rename-empty:
  merge-recursive: don't detect renames of empty files
  teach diffcore-rename to optionally ignore empty content
  make is_empty_blob_sha1 available everywhere
  drop casts from users EMPTY_TREE_SHA1_BIN
2012-04-16 12:41:49 -07:00
Lucian Poston
5e71a84a2d Add output_prefix_length to diff_options
Add output_prefix_length to diff_options. Initialize the value to 0 and only
set it when graph.c:diff_output_prefix_callback() is called.

Signed-off-by: Lucian Poston <lucian.poston@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2012-04-16 11:28:30 -07:00
Junio C Hamano
86c340e082 Merge branch 'jc/diff-algo-cleanup'
Resurrects the preparatory clean-up patches from another topic that was
discarded, as this would give a saner foundation to build on diff.algo
configuration option series.

* jc/diff-algo-cleanup:
  xdiff: PATIENCE/HISTOGRAM are not independent option bits
  xdiff: remove XDL_PATCH_* macros
2012-04-15 22:51:15 -07:00
Jeff King
90d43b0768 teach diffcore-rename to optionally ignore empty content
Our rename detection is a heuristic, matching pairs of
removed and added files with similar or identical content.
It's unlikely to be wrong when there is actual content to
compare, and we already take care not to do inexact rename
detection when there is not enough content to produce good
results.

However, we always do exact rename detection, even when the
blob is tiny or empty. It's easy to get false positives with
an empty blob, simply because it is an obvious content to
use as a boilerplate (e.g., when telling git that an empty
directory is worth tracking via an empty .gitignore).

This patch lets callers specify whether or not they are
interested in using empty files as rename sources and
destinations. The default is "yes", keeping the original
behavior. It works by detecting the empty-blob sha1 for
rename sources and destinations.

One more flexible alternative would be to allow the caller
to specify a minimum size for a blob to be "interesting" for
rename detection. But that would catch small boilerplate
files, not large ones (e.g., if you had the GPL COPYING file
in many directories).

A better alternative would be to allow a "-rename"
gitattribute to allow boilerplate files to be marked as
such. I'll leave the complexity of that solution until such
time as somebody actually wants it. The complaints we've
seen so far revolve around empty files, so let's start with
the simple thing.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2012-03-23 13:52:49 -07:00
Junio C Hamano
1e4d0875ac Merge branch 'jc/pickaxe-ignore-case'
By Junio C Hamano (2) and Ramsay Jones (1)
* jc/pickaxe-ignore-case:
  ctype.c: Fix a sparse warning
  pickaxe: allow -i to search in patch case-insensitively
  grep: use static trans-case table
2012-03-07 12:12:59 -08:00
Junio C Hamano
af050219e4 Merge branch 'zj/diff-stat-dyncol'
By Zbigniew Jędrzejewski-Szmek (8) and Junio C Hamano (1)
* zj/diff-stat-dyncol:
  : This breaks tests. Perhaps it is not worth using the decimal-width stuff
  : for this series, at least initially.
  diff --stat: add config option to limit graph width
  diff --stat: enable limiting of the graph part
  diff --stat: add a test for output with COLUMNS=40
  diff --stat: use a maximum of 5/8 for the filename part
  merge --stat: use the full terminal width
  log --stat: use the full terminal width
  show --stat: use the full terminal width
  diff --stat: use the full terminal width
  diff --stat: tests for long filenames and big change counts
2012-03-06 14:53:06 -08:00
Zbigniew Jędrzejewski-Szmek
969fe57b84 diff --stat: enable limiting of the graph part
A new option --stat-graph-width=<width> can be used to limit the width
of the graph part even is more space is available. Up to <width>
columns will be used for the graph.

If commits changing a lot of lines are displayed in a wide terminal
window (200 or more columns), and the +- graph uses the full width,
the output can be hard to comfortably scan with a horizontal movement
of human eyes. Messages wrapped to about 80 columns would be
interspersed with very long +- lines. It makes sense to limit the
width of the graph part to a fixed value (e.g. 70 columns), even if
more columns are available.

Signed-off-by: Zbigniew Jędrzejewski-Szmek <zbyszek@in.waw.pl>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2012-03-01 09:15:47 -08:00
Junio C Hamano
accccde483 pickaxe: allow -i to search in patch case-insensitively
"git log -S<string>" is a useful way to find the last commit in the
codebase that touched the <string>. As it was designed to be used by a
porcelain script to dig the history starting from a block of text that
appear in the starting commit, it never had to look for anything but an
exact match.

When used by an end user who wants to look for the last commit that
removed a string (e.g. name of a variable) that he vaguely remembers,
however, it is useful to support case insensitive match.

When given the "--regexp-ignore-case" (or "-i") option, which originally
was designed to affect case sensitivity of the search done in the commit
log part, e.g. "log --grep", the matches made with -S/-G pickaxe search is
done case insensitively now.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
2012-02-28 16:15:29 -08:00
Junio C Hamano
307ab20b33 xdiff: PATIENCE/HISTOGRAM are not independent option bits
Because the default Myers, patience and histogram algorithms cannot be in
effect at the same time, XDL_PATIENCE_DIFF and XDL_HISTOGRAM_DIFF are not
independent bits.  Instead of wasting one bit per algorithm, define a few
macros to access the few bits they occupy and update the code that access
them.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
2012-02-19 15:36:55 -08:00
Nguyễn Thái Ngọc Duy
7f814632f5 Use correct grammar in diffstat summary line
"git diff --stat" and "git apply --stat" now learn to print the line
"%d files changed, %d insertions(+), %d deletions(-)" in singular form
whenever applicable. "0 insertions" and "0 deletions" are also omitted
unless they are both zero.

This matches how versions of "diffstat" that are not prehistoric produced
their output, and also makes this line translatable.

[jc: with help from Thomas Dickey in archaeology of "diffstat"]
[jc: squashed Jonathan's updates to illustrations in tutorials and a test]

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2012-02-03 23:19:42 -08:00
René Scharfe
82889295e7 pass struct commit to diff_tree_combined_merge()
Instead of passing the hash of a commit and then searching that
same commit in the single caller, simply pass the commit directly.

Signed-off-by: René Scharfe <rene.scharfe@lsrfire.ath.cx>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-12-17 18:22:29 -08:00
René Scharfe
0041f09de6 use struct sha1_array in diff_tree_combined()
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>
2011-12-17 18:21:37 -08:00
René Scharfe
14937c2c06 diff: add option to show whole functions as context
Add the option -W/--function-context to git diff.  It is similar to
the same option of git grep and expands the context of change hunks
so that the whole surrounding function is shown.  This "natural"
context can allow changes to be understood better.

Note: GNU patch doesn't like diffs generated with the new option;
it seems to expect context lines to be the same before and after
changes.  git apply doesn't complain.

This implementation has the same shortcoming as the one in grep,
namely that there is no way to explicitly find the end of a
function.  That means that a few lines of extra context are shown,
right up to the next recognized function begins.  It's already
useful in its current form, though.

The function get_func_line() in xdiff/xemit.c is extended to work
forward as well as backward to find post-context as well as
pre-context.  It returns the position of the first found matching
line.  The func_line parameter is made optional, as we don't need
it for -W.

The enhanced function is then used in xdl_emit_diff() to extend
the context as needed.  If the added context overlaps with the
next change, it is merged into the current hunk.

Signed-off-by: Rene Scharfe <rene.scharfe@lsrfire.ath.cx>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-10-10 12:05:07 -07:00
Junio C Hamano
f946b465d7 Merge branch 'jk/color-and-pager'
* jk/color-and-pager:
  want_color: automatically fallback to color.ui
  diff: don't load color config in plumbing
  config: refactor get_colorbool function
  color: delay auto-color decision until point of use
  git_config_colorbool: refactor stdout_is_tty handling
  diff: refactor COLOR_DIFF from a flag into an int
  setup_pager: set GIT_PAGER_IN_USE
  t7006: use test_config helpers
  test-lib: add helper functions for config
  t7006: modernize calls to unset

Conflicts:
	builtin/commit.c
	parse-options.c
2011-08-28 21:19:16 -07:00
Jeff King
f1c9626105 diff: refactor COLOR_DIFF from a flag into an int
This lets us store more than just a bit flag for whether we
want color; we can also store whether we want automatic
colors. This can be useful for making the automatic-color
decision closer to the point of use.

This mostly just involves replacing DIFF_OPT_* calls with
manipulations of the flag. The biggest exception is that
calls to DIFF_OPT_TST must check for "o->use_color > 0",
which lets an "unknown" value (i.e., the default) stay at
"no color". In the previous code, a value of "-1" was not
propagated at all.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-08-18 14:35:53 -07:00
Junio C Hamano
a852aac48d Merge branch 'mg/diff-stat-count'
* mg/diff-stat-count:
  diff --stat-count: finishing touches
  diff-options.txt: describe --stat-{width,name-width,count}
  diff: introduce --stat-lines to limit the stat lines
  diff.c: omit hidden entries from namelen calculation with --stat
2011-06-29 17:03:10 -07:00
Junio C Hamano
456a4c08b8 Merge branch 'jk/diff-not-so-quick'
* jk/diff-not-so-quick:
  diff: futureproof "stop feeding the backend early" logic
  diff_tree: disable QUICK optimization with diff filter

Conflicts:
	diff.c
2011-06-06 11:40:14 -07:00
Junio C Hamano
28b9264dd6 diff: futureproof "stop feeding the backend early" logic
Refactor the "do not stop feeding the backend early" logic into a small
helper function and use it in both run_diff_files() and diff_tree() that
has the stop-early optimization. We may later add other types of diffcore
transformation that require to look at the whole result like diff-filter
does, and having the logic in a single place is essential for longer term
maintainability.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-05-31 09:21:36 -07:00
Michael J Gruber
808e1db231 diff: introduce --stat-lines to limit the stat lines
Often one is interested in the full --stat output only for commits which
change a few files, but not others, because larger restructuring gives a
--stat which fills a few screens.

Introduce a new option --stat-count=<count> which limits the --stat output
to the first <count> lines, followed by a "..." line. It can
also be given as the third parameter in
--stat=<width>,<name-width>,<count>.

Also, the unstuck form is supported analogous to the other two stat
parameters.

Signed-off-by: Michael J Gruber <git@drmicha.warpmail.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-05-27 10:44:34 -07:00
Junio C Hamano
df54e2bfd6 Merge branch 'jh/dirstat-lines'
* jh/dirstat-lines:
  Mark dirstat error messages for translation
  Improve error handling when parsing dirstat parameters
  New --dirstat=lines mode, doing dirstat analysis based on diffstat
  Allow specifying --dirstat cut-off percentage as a floating point number
  Add config variable for specifying default --dirstat behavior
  Refactor --dirstat parsing; deprecate --cumulative and --dirstat-by-file
  Make --dirstat=0 output directories that contribute < 0.1% of changes
  Add several testcases for --dirstat and friends
2011-05-13 11:01:32 -07:00
Junio C Hamano
22dbeee715 Merge branch 'jc/fix-diff-files-unmerged'
* jc/fix-diff-files-unmerged:
  diff-files: show unmerged entries correctly
  diff: remove often unused parameters from diff_unmerge()
  diff.c: return filepair from diff_unmerge()
  test: use $_z40 from test-lib
2011-05-06 10:52:58 -07:00
Johan Herland
1c57a627bf New --dirstat=lines mode, doing dirstat analysis based on diffstat
This patch adds an alternative implementation of show_dirstat(), called
show_dirstat_by_line(), which uses the more expensive diffstat analysis
(as opposed to show_dirstat()'s own (relatively inexpensive) analysis)
to derive the numbers from which the --dirstat output is computed.

The alternative implementation is controlled by the new "lines" parameter
to the --dirstat option (or the diff.dirstat config variable).

For binary files, the diffstat analysis counts bytes instead of lines,
so to prevent binary files from dominating the dirstat results, the
byte counts for binary files are divided by 64 before being compared to
their textual/line-based counterparts. This is a stupid and ugly - but
very cheap - heuristic.

In linux-2.6.git, running the three different --dirstat modes:

  time git diff v2.6.20..v2.6.30 --dirstat=changes > /dev/null
vs.
  time git diff v2.6.20..v2.6.30 --dirstat=lines > /dev/null
vs.
  time git diff v2.6.20..v2.6.30 --dirstat=files > /dev/null

yields the following average runtimes on my machine:

 - "changes" (default): ~6.0 s
 - "lines":             ~9.6 s
 - "files":             ~0.1 s

So, as expected, there's a considerable performance hit (~60%) by going
through the full diffstat analysis as compared to the default "changes"
analysis (obviously, "files" is much faster than both). As such, the
"lines" mode is probably only useful if you really need the --dirstat
numbers to be consistent with the numbers returned from the other
--*stat options.

The patch also includes documentation and tests for the new dirstat mode.

Improved-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Johan Herland <johan@herland.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-04-29 11:22:55 -07:00