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Author SHA1 Message Date
Junio C Hamano
c0d75f0e2e Merge branch 'sb/diff-blobfind-pickaxe'
"diff" family of commands learned "--find-object=<object-id>" option
to limit the findings to changes that involve the named object.

* sb/diff-blobfind-pickaxe:
  diff: use HAS_MULTI_BITS instead of counting bits manually
  diff: properly error out when combining multiple pickaxe options
  diffcore: add a pickaxe option to find a specific blob
  diff: introduce DIFF_PICKAXE_KINDS_MASK
  diff: migrate diff_flags.pickaxe_ignore_case to a pickaxe_opts bit
  diff.h: make pickaxe_opts an unsigned bit field
2018-01-23 13:16:37 -08:00
Junio C Hamano
6366dd9000 Merge branch 'jk/doc-diff-options'
Doc update.

* jk/doc-diff-options:
  docs/diff-options: clarify scope of diff-filter types
2018-01-09 14:32:57 -08:00
Stefan Beller
15af58c1ad diffcore: add a pickaxe option to find a specific blob
Sometimes users are given a hash of an object and they want to
identify it further (ex.: Use verify-pack to find the largest blobs,
but what are these? or [1])

One might be tempted to extend git-describe to also work with blobs,
such that `git describe <blob-id>` gives a description as
'<commit-ish>:<path>'.  This was implemented at [2]; as seen by the sheer
number of responses (>110), it turns out this is tricky to get right.
The hard part to get right is picking the correct 'commit-ish' as that
could be the commit that (re-)introduced the blob or the blob that
removed the blob; the blob could exist in different branches.

Junio hinted at a different approach of solving this problem, which this
patch implements. Teach the diff machinery another flag for restricting
the information to what is shown. For example:

    $ ./git log --oneline --find-object=v2.0.0:Makefile
    b2feb64309 Revert the whole "ask curl-config" topic for now
    47fbfded53 i18n: only extract comments marked with "TRANSLATORS:"

we observe that the Makefile as shipped with 2.0 was appeared in
v1.9.2-471-g47fbfded53 and in v2.0.0-rc1-5-gb2feb6430b.  The
reason why these commits both occur prior to v2.0.0 are evil
merges that are not found using this new mechanism.

[1] https://stackoverflow.com/questions/223678/which-commit-has-this-blob
[2] https://public-inbox.org/git/20171028004419.10139-1-sbeller@google.com/

Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-01-04 15:02:40 -08:00
Jeff King
46af107bde docs/diff-options: clarify scope of diff-filter types
The same document for "--diff-filter" is included by many
programs in the diff family. Because it mentions all
possible types (added, removed, etc), this may imply to the
reader that all types can be generated by a particular
command. But this isn't necessarily the case; "diff-files"
cannot generally produce an "Added" entry, since the diff is
limited to what is already in the index.

Let's make it clear that the list here is the full one, and
does not imply anything about what a particular invocation
may produce.

Note that conditionally including items (e.g., omitting
"Added" in the git-diff-files manpage) isn't the right
solution here for two reasons:

  - The problem isn't diff-files, but doing an index to
    working tree diff. "git diff" can do the same diff, but
    also has other modes where "Added" does show up.

  - The direction of the diff matters. Doing "diff-files -R"
    can get you Added entries (but not Deleted ones).

So it's best just to explain that the set of available types
depends on the specific diff invocation.

Reported-by: John Cheng <johnlicheng@gmail.com>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-01-04 11:09:47 -08:00
Jonathan Tan
2477ab2ea8 diff: support anchoring line(s)
Teach diff a new algorithm, one that attempts to prevent user-specified
lines from appearing as a deletion or addition in the end result. The
end user can use this by specifying "--anchored=<text>" one or more
times when using Git commands like "diff" and "show".

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-11-28 10:40:04 +09:00
Junio C Hamano
10f65c239a Merge branch 'jc/ignore-cr-at-eol'
The "diff" family of commands learned to ignore differences in
carriage return at the end of line.

* jc/ignore-cr-at-eol:
  diff: --ignore-cr-at-eol
  xdiff: reassign xpparm_t.flags bits
2017-11-27 11:06:31 +09:00
Junio C Hamano
e9282f02b2 diff: --ignore-cr-at-eol
A new option --ignore-cr-at-eol tells the diff machinery to treat a
carriage-return at the end of a (complete) line as if it does not
exist.

Just like other "--ignore-*" options to ignore various kinds of
whitespace differences, this will help reviewing the real changes
you made without getting distracted by spurious CRLF<->LF conversion
made by your editor program.

Helped-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
[jch: squashed in command line completion by Dscho]
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-11-08 10:05:27 +09:00
Junio C Hamano
662ac3b3a8 Merge branch 'cn/diff-indent-no-longer-is-experimental'
Doc update.

* cn/diff-indent-no-longer-is-experimental:
  diff: --indent-heuristic is no longer experimental
2017-11-06 13:11:27 +09:00
Carlos Martín Nieto
bab76141da diff: --indent-heuristic is no longer experimental
This heuristic has been the default since 2.14 so we should not confuse our
users by saying that it's experimental and off by default.

Signed-off-by: Carlos Martín Nieto <cmn@dwim.me>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-11-02 14:51:24 +09:00
Junio C Hamano
0b96358479 Merge branch 'jt/diff-color-move-fix'
A handful of bugfixes and an improvement to "diff --color-moved".

* jt/diff-color-move-fix:
  diff: define block by number of alphanumeric chars
  diff: respect MIN_BLOCK_LENGTH for last block
  diff: avoid redundantly clearing a flag
2017-08-26 22:55:04 -07:00
Junio C Hamano
b6c4058f97 Merge branch 'sb/diff-color-move'
"git diff" has been taught to optionally paint new lines that are
the same as deleted lines elsewhere differently from genuinely new
lines.

* sb/diff-color-move: (25 commits)
  diff: document the new --color-moved setting
  diff.c: add dimming to moved line detection
  diff.c: color moved lines differently, plain mode
  diff.c: color moved lines differently
  diff.c: buffer all output if asked to
  diff.c: emit_diff_symbol learns about DIFF_SYMBOL_SUMMARY
  diff.c: emit_diff_symbol learns about DIFF_SYMBOL_STAT_SEP
  diff.c: convert word diffing to use emit_diff_symbol
  diff.c: convert show_stats to use emit_diff_symbol
  diff.c: convert emit_binary_diff_body to use emit_diff_symbol
  submodule.c: migrate diff output to use emit_diff_symbol
  diff.c: emit_diff_symbol learns DIFF_SYMBOL_REWRITE_DIFF
  diff.c: emit_diff_symbol learns about DIFF_SYMBOL_BINARY_FILES
  diff.c: emit_diff_symbol learns DIFF_SYMBOL_HEADER
  diff.c: emit_diff_symbol learns DIFF_SYMBOL_FILEPAIR_{PLUS, MINUS}
  diff.c: emit_diff_symbol learns DIFF_SYMBOL_CONTEXT_INCOMPLETE
  diff.c: emit_diff_symbol learns DIFF_SYMBOL_WORDS[_PORCELAIN]
  diff.c: migrate emit_line_checked to use emit_diff_symbol
  diff.c: emit_diff_symbol learns DIFF_SYMBOL_NO_LF_EOF
  diff.c: emit_diff_symbol learns DIFF_SYMBOL_CONTEXT_FRAGINFO
  ...
2017-08-26 22:55:03 -07:00
Junio C Hamano
b55b936038 Merge branch 'ah/doc-wserrorhighlight' into maint
Doc update.

* ah/doc-wserrorhighlight:
  doc: add missing values "none" and "default" for diff.wsErrorHighlight
2017-08-23 14:33:51 -07:00
Jonathan Tan
f0b8fb6e59 diff: define block by number of alphanumeric chars
The existing behavior of diff --color-moved=zebra does not define the
minimum size of a block at all, instead relying on a heuristic applied
later to filter out sets of adjacent moved lines that are shorter than 3
lines long. This can be confusing, because a block could thus be colored
as moved at the source but not at the destination (or vice versa),
depending on its neighbors.

Instead, teach diff that the minimum size of a block is 20 alphanumeric
characters, the same heuristic used by "git blame". This allows diff to
still exclude uninteresting lines appearing on their own (such as those
solely consisting of one or a few closing braces), as was the intention
of the adjacent-moved-line heuristic.

This requires a change in some tests in that some of their lines are no
longer considered to be part of a block, because they are too short.

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-08-16 11:44:00 -07:00
Junio C Hamano
4c244c25f0 Merge branch 'ah/doc-wserrorhighlight'
Doc update.

* ah/doc-wserrorhighlight:
  doc: add missing values "none" and "default" for diff.wsErrorHighlight
2017-08-11 13:27:04 -07:00
Anthony Sottile
bc9b7e207f diff-options doc: grammar fix
Signed-off-by: Anthony Sottile <asottile@umich.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-07-31 09:57:12 -07:00
Andreas Heiduk
c0bb6d9cef doc: add missing values "none" and "default" for diff.wsErrorHighlight
The values have eluded documentation so far. While at it streamline
the wording by grouping relevant parts together.

Signed-off-by: Andreas Heiduk <asheiduk@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-07-25 14:30:49 -07:00
Stefan Beller
61e89eaae8 diff: document the new --color-moved setting
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-06-30 13:59:42 -07:00
Andreas Heiduk
860cd699c2 Documentation: improve description for core.quotePath
Linking the description for pathname quoting to the configuration
variable "core.quotePath" removes inconstistent and incomplete
sections while also giving two hints how to deal with it: Either with
"-c core.quotePath=false" or with "-z".

Signed-off-by: Andreas Heiduk <asheiduk@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-03-02 11:40:51 -08:00
Junio C Hamano
831bd5e775 Merge branch 'rh/diff-orderfile-doc'
Documentation fix.

* rh/diff-orderfile-doc:
  diff: document the format of the -O (diff.orderFile) file
  diff: document behavior of relative diff.orderFile
2017-01-23 15:59:23 -08:00
Richard Hansen
874444b704 diff: document the format of the -O (diff.orderFile) file
Signed-off-by: Richard Hansen <hansenr@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-01-15 16:42:16 -08:00
Vegard Nossum
c488867793 diff: add interhunk context config option
The --inter-hunk-context= option was added in commit 6d0e674a57
("diff: add option to show context between close hunks"). This patch
allows configuring a default for this option.

Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-01-12 12:55:43 -08:00
Junio C Hamano
650360210a Merge branch 'nd/ita-empty-commit'
When new paths were added by "git add -N" to the index, it was
enough to circumvent the check by "git commit" to refrain from
making an empty commit without "--allow-empty".  The same logic
prevented "git status" to show such a path as "new file" in the
"Changes not staged for commit" section.

* nd/ita-empty-commit:
  commit: don't be fooled by ita entries when creating initial commit
  commit: fix empty commit creation when there's no changes but ita entries
  diff: add --ita-[in]visible-in-index
  diff-lib: allow ita entries treated as "not yet exist in index"
2016-10-27 14:58:50 -07:00
Junio C Hamano
e5272d304a Merge branch 'jc/ws-error-highlight'
"git diff/log --ws-error-highlight=<kind>" lacked the corresponding
configuration variable to set it by default.

* jc/ws-error-highlight:
  diff: introduce diff.wsErrorHighlight option
  diff.c: move ws-error-highlight parsing helpers up
  diff.c: refactor parse_ws_error_highlight()
  t4015: split out the "setup" part of ws-error-highlight test
2016-10-26 13:14:43 -07:00
Nguyễn Thái Ngọc Duy
b42b451919 diff: add --ita-[in]visible-in-index
The option --ita-invisible-in-index exposes the "ita_invisible_in_index"
diff flag to outside to allow easier experimentation with this new mode.
The "plan" is to make --ita-invisible-in-index default to keep consistent
behavior with 'status' and 'commit', but a bunch other commands like
'apply', 'merge', 'reset'.... need to be taken into consideration as well.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-10-24 10:47:51 -07:00
Junio C Hamano
a17505f262 diff: introduce diff.wsErrorHighlight option
With the preparatory steps, it has become trivial to teach the
system a new diff.wsErrorHighlight configuration that gives the
default value for --ws-error-highlight command line option.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-10-04 15:49:05 -07:00
Junio C Hamano
b7af6ae5cf Merge branch 'mh/diff-indent-heuristic'
Output from "git diff" can be made easier to read by selecting
which lines are common and which lines are added/deleted
intelligently when the lines before and after the changed section
are the same.  A command line option is added to help with the
experiment to find a good heuristics.

* mh/diff-indent-heuristic:
  blame: honor the diff heuristic options and config
  parse-options: add parse_opt_unknown_cb()
  diff: improve positioning of add/delete blocks in diffs
  xdl_change_compact(): introduce the concept of a change group
  recs_match(): take two xrecord_t pointers as arguments
  is_blank_line(): take a single xrecord_t as argument
  xdl_change_compact(): only use heuristic if group can't be matched
  xdl_change_compact(): fix compaction heuristic to adjust ixo
2016-09-26 16:09:16 -07:00
Michael Haggerty
5b162879e9 blame: honor the diff heuristic options and config
Teach "git blame" and "git annotate" the --compaction-heuristic and
--indent-heuristic options that are now supported by "git diff".

Also teach them to honor the `diff.compactionHeuristic` and
`diff.indentHeuristic` configuration options.

It would be conceivable to introduce separate configuration options for
"blame" and "annotate"; for example `blame.compactionHeuristic` and
`blame.indentHeuristic`. But it would be confusing to users if blame
output is inconsistent with diff output, so it makes more sense for them
to respect the same configuration.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-09-19 10:25:11 -07:00
Michael Haggerty
433860f3d0 diff: improve positioning of add/delete blocks in diffs
Some groups of added/deleted lines in diffs can be slid up or down,
because lines at the edges of the group are not unique. Picking good
shifts for such groups is not a matter of correctness but definitely has
a big effect on aesthetics. For example, consider the following two
diffs. The first is what standard Git emits:

    --- a/9c572b21dd090a1e5c5bb397053bf8043ffe7fb4:git-send-email.perl
    +++ b/6dcfa306f2b67b733a7eb2d7ded1bc9987809edb:git-send-email.perl
    @@ -231,6 +231,9 @@ if (!defined $initial_reply_to && $prompting) {
     }

     if (!$smtp_server) {
    +       $smtp_server = $repo->config('sendemail.smtpserver');
    +}
    +if (!$smtp_server) {
            foreach (qw( /usr/sbin/sendmail /usr/lib/sendmail )) {
                    if (-x $_) {
                            $smtp_server = $_;

The following diff is equivalent, but is obviously preferable from an
aesthetic point of view:

    --- a/9c572b21dd090a1e5c5bb397053bf8043ffe7fb4:git-send-email.perl
    +++ b/6dcfa306f2b67b733a7eb2d7ded1bc9987809edb:git-send-email.perl
    @@ -230,6 +230,9 @@ if (!defined $initial_reply_to && $prompting) {
            $initial_reply_to =~ s/(^\s+|\s+$)//g;
     }

    +if (!$smtp_server) {
    +       $smtp_server = $repo->config('sendemail.smtpserver');
    +}
     if (!$smtp_server) {
            foreach (qw( /usr/sbin/sendmail /usr/lib/sendmail )) {
                    if (-x $_) {

This patch teaches Git to pick better positions for such "diff sliders"
using heuristics that take the positions of nearby blank lines and the
indentation of nearby lines into account.

The existing Git code basically always shifts such "sliders" as far down
in the file as possible. The only exception is when the slider can be
aligned with a group of changed lines in the other file, in which case
Git favors depicting the change as one add+delete block rather than one
add and a slightly offset delete block. This naive algorithm often
yields ugly diffs.

Commit d634d61ed6 improved the situation somewhat by preferring to
position add/delete groups to make their last line a blank line, when
that is possible. This heuristic does more good than harm, but (1) it
can only help if there are blank lines in the right places, and (2)
always picks the last blank line, even if there are others that might be
better. The end result is that it makes perhaps 1/3 as many errors as
the default Git algorithm, but that still leaves a lot of ugly diffs.

This commit implements a new and much better heuristic for picking
optimal "slider" positions using the following approach: First observe
that each hypothetical positioning of a diff slider introduces two
splits: one between the context lines preceding the group and the first
added/deleted line, and the other between the last added/deleted line
and the first line of context following it. It tries to find the
positioning that creates the least bad splits.

Splits are evaluated based only on the presence and locations of nearby
blank lines, and the indentation of lines near the split. Basically, it
prefers to introduce splits adjacent to blank lines, between lines that
are indented less, and between lines with the same level of indentation.
In more detail:

1. It measures the following characteristics of a proposed splitting
   position in a `struct split_measurement`:

   * the number of blank lines above the proposed split
   * whether the line directly after the split is blank
   * the number of blank lines following that line
   * the indentation of the nearest non-blank line above the split
   * the indentation of the line directly below the split
   * the indentation of the nearest non-blank line after that line

2. It combines the measured attributes using a bunch of
   empirically-optimized weighting factors to derive a `struct
   split_score` that measures the "badness" of splitting the text at
   that position.

3. It combines the `split_score` for the top and the bottom of the
   slider at each of its possible positions, and selects the position
   that has the best `split_score`.

I determined the initial set of weighting factors by collecting a corpus
of Git histories from 29 open-source software projects in various
programming languages. I generated many diffs from this corpus, and
determined the best positioning "by eye" for about 6600 diff sliders. I
used about half of the repositories in the corpus (corresponding to
about 2/3 of the sliders) as a training set, and optimized the weights
against this corpus using a crude automated search of the parameter
space to get the best agreement with the manually-determined values.
Then I tested the resulting heuristic against the full corpus. The
results are summarized in the following table, in column `indent-1`:

| repository            | count |      Git 2.9.0 |     compaction | compaction-fixed |       indent-1 |       indent-2 |
| --------------------- | ----- | -------------- | -------------- | ---------------- | -------------- | -------------- |
| afnetworking          |   109 |    89  (81.7%) |    37  (33.9%) |      37  (33.9%) |     2   (1.8%) |     2   (1.8%) |
| alamofire             |    30 |    18  (60.0%) |    14  (46.7%) |      15  (50.0%) |     0   (0.0%) |     0   (0.0%) |
| angular               |   184 |   127  (69.0%) |    39  (21.2%) |      23  (12.5%) |     5   (2.7%) |     5   (2.7%) |
| animate               |   313 |     2   (0.6%) |     2   (0.6%) |       2   (0.6%) |     2   (0.6%) |     2   (0.6%) |
| ant                   |   380 |   356  (93.7%) |   152  (40.0%) |     148  (38.9%) |    15   (3.9%) |    15   (3.9%) | *
| bugzilla              |   306 |   263  (85.9%) |   109  (35.6%) |      99  (32.4%) |    14   (4.6%) |    15   (4.9%) | *
| corefx                |   126 |    91  (72.2%) |    22  (17.5%) |      21  (16.7%) |     6   (4.8%) |     6   (4.8%) |
| couchdb               |    78 |    44  (56.4%) |    26  (33.3%) |      28  (35.9%) |     6   (7.7%) |     6   (7.7%) | *
| cpython               |   937 |   158  (16.9%) |    50   (5.3%) |      49   (5.2%) |     5   (0.5%) |     5   (0.5%) | *
| discourse             |   160 |    95  (59.4%) |    42  (26.2%) |      36  (22.5%) |    18  (11.2%) |    13   (8.1%) |
| docker                |   307 |   194  (63.2%) |   198  (64.5%) |     253  (82.4%) |     8   (2.6%) |     8   (2.6%) | *
| electron              |   163 |   132  (81.0%) |    38  (23.3%) |      39  (23.9%) |     6   (3.7%) |     6   (3.7%) |
| git                   |   536 |   470  (87.7%) |    73  (13.6%) |      78  (14.6%) |    16   (3.0%) |    16   (3.0%) | *
| gitflow               |   127 |     0   (0.0%) |     0   (0.0%) |       0   (0.0%) |     0   (0.0%) |     0   (0.0%) |
| ionic                 |   133 |    89  (66.9%) |    29  (21.8%) |      38  (28.6%) |     1   (0.8%) |     1   (0.8%) |
| ipython               |   482 |   362  (75.1%) |   167  (34.6%) |     169  (35.1%) |    11   (2.3%) |    11   (2.3%) | *
| junit                 |   161 |   147  (91.3%) |    67  (41.6%) |      66  (41.0%) |     1   (0.6%) |     1   (0.6%) | *
| lighttable            |    15 |     5  (33.3%) |     0   (0.0%) |       2  (13.3%) |     0   (0.0%) |     0   (0.0%) |
| magit                 |    88 |    75  (85.2%) |    11  (12.5%) |       9  (10.2%) |     1   (1.1%) |     0   (0.0%) |
| neural-style          |    28 |     0   (0.0%) |     0   (0.0%) |       0   (0.0%) |     0   (0.0%) |     0   (0.0%) |
| nodejs                |   781 |   649  (83.1%) |   118  (15.1%) |     111  (14.2%) |     4   (0.5%) |     5   (0.6%) | *
| phpmyadmin            |   491 |   481  (98.0%) |    75  (15.3%) |      48   (9.8%) |     2   (0.4%) |     2   (0.4%) | *
| react-native          |   168 |   130  (77.4%) |    79  (47.0%) |      81  (48.2%) |     0   (0.0%) |     0   (0.0%) |
| rust                  |   171 |   128  (74.9%) |    30  (17.5%) |      27  (15.8%) |    16   (9.4%) |    14   (8.2%) |
| spark                 |   186 |   149  (80.1%) |    52  (28.0%) |      52  (28.0%) |     2   (1.1%) |     2   (1.1%) |
| tensorflow            |   115 |    66  (57.4%) |    48  (41.7%) |      48  (41.7%) |     5   (4.3%) |     5   (4.3%) |
| test-more             |    19 |    15  (78.9%) |     2  (10.5%) |       2  (10.5%) |     1   (5.3%) |     1   (5.3%) | *
| test-unit             |    51 |    34  (66.7%) |    14  (27.5%) |       8  (15.7%) |     2   (3.9%) |     2   (3.9%) | *
| xmonad                |    23 |    22  (95.7%) |     2   (8.7%) |       2   (8.7%) |     1   (4.3%) |     1   (4.3%) | *
| --------------------- | ----- | -------------- | -------------- | ---------------- | -------------- | -------------- |
| totals                |  6668 |  4391  (65.9%) |  1496  (22.4%) |    1491  (22.4%) |   150   (2.2%) |   144   (2.2%) |
| totals (training set) |  4552 |  3195  (70.2%) |  1053  (23.1%) |    1061  (23.3%) |    86   (1.9%) |    88   (1.9%) |
| totals (test set)     |  2116 |  1196  (56.5%) |   443  (20.9%) |     430  (20.3%) |    64   (3.0%) |    56   (2.6%) |

In this table, the numbers are the count and percentage of human-rated
sliders that the corresponding algorithm got *wrong*. The columns are

* "repository" - the name of the repository used. I used the diffs
  between successive non-merge commits on the HEAD branch of the
  corresponding repository.

* "count" - the number of sliders that were human-rated. I chose most,
  but not all, sliders to rate from those among which the various
  algorithms gave different answers.

* "Git 2.9.0" - the default algorithm used by `git diff` in Git 2.9.0.

* "compaction" - the heuristic used by `git diff --compaction-heuristic`
  in Git 2.9.0.

* "compaction-fixed" - the heuristic used by `git diff
  --compaction-heuristic` after the fixes from earlier in this patch
  series. Note that the results are not dramatically different than
  those for "compaction". Both produce non-ideal diffs only about 1/3 as
  often as the default `git diff`.

* "indent-1" - the new `--indent-heuristic` algorithm, using the first
  set of weighting factors, determined as described above.

* "indent-2" - the new `--indent-heuristic` algorithm, using the final
  set of weighting factors, determined as described below.

* `*` - indicates that repo was part of training set used to determine
  the first set of weighting factors.

The fact that the heuristic performed nearly as well on the test set as
on the training set in column "indent-1" is a good indication that the
heuristic was not over-trained. Given that fact, I ran a second round of
optimization, using the entire corpus as the training set. The resulting
set of weights gave the results in column "indent-2". These are the
weights included in this patch.

The final result gives consistently and significantly better results
across the whole corpus than either `git diff` or `git diff
--compaction-heuristic`. It makes only about 1/30 as many errors as the
former and about 1/10 as many errors as the latter. (And a good fraction
of the remaining errors are for diffs that involve weirdly-formatted
code, sometimes apparently machine-generated.)

The tools that were used to do this optimization and analysis, along
with the human-generated data values, are recorded in a separate project
[1].

This patch adds a new command-line option `--indent-heuristic`, and a
new configuration setting `diff.indentHeuristic`, that activate this
heuristic. This interface is only meant for testing purposes, and should
be finalized before including this change in any release.

[1] https://github.com/mhagger/diff-slider-tools

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-09-19 10:25:11 -07:00
Jacob Keller
fd47ae6a5b diff: teach diff to display submodule difference with an inline diff
Teach git-diff and friends a new format for displaying the difference
of a submodule. The new format is an inline diff of the contents of the
submodule between the commit range of the update. This allows the user
to see the actual code change caused by a submodule update.

Add tests for the new format and option.

Signed-off-by: Jacob Keller <jacob.keller@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-08-31 18:07:10 -07:00
Jacob Keller
660e113ce1 graph: add support for --line-prefix on all graph-aware output
Add an extension to git-diff and git-log (and any other graph-aware
displayable output) such that "--line-prefix=<string>" will print the
additional line-prefix on every line of output.

To make this work, we have to fix a few bugs in the graph API that force
graph_show_commit_msg to be used only when you have a valid graph.
Additionally, we extend the default_diff_output_prefix handler to work
even when no graph is enabled.

This is somewhat of a hack on top of the graph API, but I think it
should be acceptable here.

This will be used by a future extension of submodule display which
displays the submodule diff as the actual diff between the pre and post
commit in the submodule project.

Add some tests for both git-log and git-diff to ensure that the prefix
is honored correctly.

Signed-off-by: Jacob Keller <jacob.keller@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-08-31 18:07:09 -07:00
Junio C Hamano
c3531e0385 Merge branch 'jc/doc-diff-filter-exclude'
Belated doc update for a feature added in v1.8.5.

* jc/doc-diff-filter-exclude:
  diff: document diff-filter exclusion
2016-07-25 14:13:41 -07:00
Junio C Hamano
16726cfa0c diff: document diff-filter exclusion
In v1.8.5 days, 7f2ea5f0 (diff: allow lowercase letter to specify
what change class to exclude, 2013-07-17) taught the "--diff-filter"
mechanism to take lowercase letters as exclusion, but we forgot to
document it.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-07-14 12:17:47 -07:00
Junio C Hamano
e5f7675544 Merge branch 'jk/diff-compact-heuristic'
It turns out that the earlier effort to update the heuristics may
want to use a bit more time to mature.  Turn it off by default.

* jk/diff-compact-heuristic:
  diff: disable compaction heuristic for now
2016-06-10 15:26:06 -07:00
Junio C Hamano
5580b271af diff: disable compaction heuristic for now
http://lkml.kernel.org/g/20160610075043.GA13411@sigill.intra.peff.net
reports that a change to add a new "function" with common ending
with the existing one at the end of the file is shown like this:

    def foo
      do_foo_stuff()

   +  common_ending()
   +end
   +
   +def bar
   +  do_bar_stuff()
   +
      common_ending()
    end

when the new heuristic is in use.  In reality, the change is to add
the blank line before "def bar" and everything below, which is what
the code without the new heuristic shows.

Disable the heuristics by default, and resurrect the documentation
for the option and the configuration variables, while clearly
marking the feature as still experimental.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-06-10 13:45:23 -07:00
Junio C Hamano
1cca17dfff Documentation: fix linkgit references
There are a handful of incorrect "linkgit:<page>[<section>]"
instances in our documentation set.

 * Some have an extra colon after "linkgit:"; fix them by removing
   the extra colon;

 * Some refer to a page outside the Git suite, namely curl(1); fix
   them by using the `curl(1)` that already appears on the same page
   for the same purpose of referring the readers to its manual page.

 * Some spell the name of the page incorrectly, e.g. "rev-list" when
   they mean "git-rev-list"; fix them.

 * Some list the manual section incorrectly; fix them to make sure
   they match what is at the top of the target of the link.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-05-09 15:44:14 -07:00
Junio C Hamano
a3fa565327 Merge branch 'es/format-patch-doc-hide-no-patch' into maint
"git format-patch --help" showed `-s` and `--no-patch` as if these
are valid options to the command.  We already hide `--patch` option
from the documentation, because format-patch is about showing the
diff, and the documentation now hides these options as well.

* es/format-patch-doc-hide-no-patch:
  git-format-patch.txt: don't show -s as shorthand for multiple options
2016-05-02 14:24:06 -07:00
Junio C Hamano
77085a616b diff: undocument the compaction heuristic knobs for experimentation
It seems that people around here are all happy with the updated
heuristics used to decide where the hunks are separated.  Let's keep
that as the default.  Even though we do not expect too much trouble
from the difference between the old and the new algorithms, just in
case let's leave the implementation of the knobs to turn it off for
emergencies.  There is no longer need for documenting them, though.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-05-02 10:36:36 -07:00
Stefan Beller
d634d61ed6 xdiff: implement empty line chunk heuristic
In order to produce the smallest possible diff and combine several diff
hunks together, we implement a heuristic from GNU Diff which moves diff
hunks forward as far as possible when we find common context above and
below a diff hunk. This sometimes produces less readable diffs when
writing C, Shell, or other programming languages, ie:

...
 /*
+ *
+ *
+ */
+
+/*
...

instead of the more readable equivalent of

...
+/*
+ *
+ *
+ */
+
 /*
...

Implement the following heuristic to (optionally) produce the desired
output.

  If there are diff chunks which can be shifted around, shift each hunk
  such that the last common empty line is below the chunk with the rest
  of the context above.

This heuristic appears to resolve the above example and several other
common issues without producing significantly weird results. However, as
with any heuristic it is not really known whether this will always be
more optimal. Thus, it can be disabled via diff.compactionHeuristic.

Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-04-19 10:53:34 -07:00
Eric Sunshine
b73a1bcc1a git-format-patch.txt: don't show -s as shorthand for multiple options
git-format-patch recognizes -s as shorthand only for --signoff, however,
its documentation shows -s as shorthand for both --signoff and
--no-patch. Resolve this confusion by suppressing the bogus -s shorthand
for --no-patch.

While here, also avoid showing the --no-patch option in git-format-patch
documentation since it doesn't make sense to ask to suppress the patch
while at the same time explicitly asking to format the patch (which,
after all, is the purpose of git-format-patch).

Reported-by: Kevin Brodsky <corax26@gmail.com>
Signed-off-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-04-04 13:46:54 -07:00
Ori Avtalion
30211fb68d Documentation: git diff --check detects conflict markers
Signed-off-by: Ori Avtalion <ori@avtalion.name>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-03-29 13:14:50 -07:00
Michael J Gruber
2c15c00651 Documentation/diff: give --word-diff-regex=. example
It's just so useful.

Signed-off-by: Michael J Gruber <git@drmicha.warpmail.net>
Signed-off-by: Jeff King <peff@peff.net>
2015-11-24 18:38:46 -05:00
Junio C Hamano
4be33f7222 Merge branch 'mm/log-format-raw-doc' into maint
Clarify that "log --raw" and "log --format=raw" are unrelated
concepts.

* mm/log-format-raw-doc:
  Documentation/log: clarify sha1 non-abbreviation in log --raw
  Documentation/log: clarify what --raw means
2015-06-16 14:33:43 -07:00
Junio C Hamano
709cd912d4 Merge branch 'jc/diff-ws-error-highlight'
Allow whitespace breakages in deleted and context lines to be also
painted in the output.

* jc/diff-ws-error-highlight:
  diff.c: --ws-error-highlight=<kind> option
  diff.c: add emit_del_line() and emit_context_line()
  t4015: separate common setup and per-test expectation
  t4015: modernise style
2015-06-11 09:29:51 -07:00
Junio C Hamano
96b7f93ac8 Merge branch 'jk/asciidoc-markup-fix' into maint
Various documentation mark-up fixes to make the output more
consistent in general and also make AsciiDoctor (an alternative
formatter) happier.

* jk/asciidoc-markup-fix:
  doc: convert AsciiDoc {?foo} to ifdef::foo[]
  doc: put example URLs and emails inside literal backticks
  doc: drop backslash quoting of some curly braces
  doc: convert \--option to --option
  doc/add: reformat `--edit` option
  doc: fix length of underlined section-title
  doc: fix hanging "+"-continuation
  doc: fix unquoted use of "{type}"
  doc: fix misrendering due to `single quote'
2015-06-05 12:00:19 -07:00
Junio C Hamano
abcbafedbf Merge branch 'mm/log-format-raw-doc'
Clarify that "log --raw" and "log --format=raw" are unrelated
concepts.

* mm/log-format-raw-doc:
  Documentation/log: clarify sha1 non-abbreviation in log --raw
  Documentation/log: clarify what --raw means
2015-06-01 12:45:18 -07:00
Junio C Hamano
b8767f791c diff.c: --ws-error-highlight=<kind> option
Traditionally, we only cared about whitespace breakages introduced
in new lines.  Some people want to paint whitespace breakages on old
lines, too.  When they see a whitespace breakage on a new line, they
can spot the same kind of whitespace breakage on the corresponding
old line and want to say "Ah, those breakages are there but they
were inherited from the original, so let's not touch them for now."

Introduce `--ws-error-highlight=<kind>` option, that lets them pass
a comma separated list of `old`, `new`, and `context` to specify
what lines to highlight whitespace errors on.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
2015-05-26 23:00:01 -07:00
Junio C Hamano
d1caa58954 Merge branch 'jk/asciidoc-markup-fix'
Various documentation mark-up fixes to make the output more
consistent in general and also make AsciiDoctor (an alternative
formatter) happier.

* jk/asciidoc-markup-fix:
  doc: convert AsciiDoc {?foo} to ifdef::foo[]
  doc: put example URLs and emails inside literal backticks
  doc: drop backslash quoting of some curly braces
  doc: convert \--option to --option
  doc/add: reformat `--edit` option
  doc: fix length of underlined section-title
  doc: fix hanging "+"-continuation
  doc: fix unquoted use of "{type}"
  doc: fix misrendering due to `single quote'
2015-05-22 12:41:50 -07:00
Matthieu Moy
d89df367f6 Documentation/log: clarify what --raw means
There are several "raw formats", and describing --raw as "Generate the
raw format" in the documentation for git-log seems to imply that it
generates the raw *log* format.

Clarify the wording by saying "raw diff format" explicitly, and make a
special-case for "git log": "git log --raw" does not just change the
format, it shows something which is not shown by default.

Signed-off-by: Matthieu Moy <Matthieu.Moy@imag.fr>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2015-05-18 13:42:52 -07:00
Jeff King
d0258b93e6 doc: convert AsciiDoc {?foo} to ifdef::foo[]
The former seems to just be syntactic sugar for the latter.
And as it's sugar that AsciiDoctor doesn't understand, it
would be nice to avoid it. Since there are only two spots,
and the resulting source is not significantly harder to
read, it's worth doing.

Note that this does slightly affect the generated HTML (it
has an extra newline), but the rendered result for both HTML
and docbook should be the same (since the newline is not
syntactically significant there).

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2015-05-14 09:38:29 -07:00
Nguyễn Thái Ngọc Duy
da0005b885 *config.txt: stick to camelCase naming convention
This should improve readability. Compare "thislongname" and
"thisLongName". The following keys are left in unchanged. We can
decide what to do with them later.

 - am.keepcr
 - core.autocrlf .safecrlf .trustctime
 - diff.dirstat .noprefix
 - gitcvs.usecrlfattr
 - gui.blamehistoryctx .trustmtime
 - pull.twohead
 - receive.autogc
 - sendemail.signedoffbycc .smtpsslcertpath .suppresscc

Helped-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2015-03-13 22:13:46 -07:00