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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 14:47:53 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 14:47:53 +0000
commitc8bae7493d2f2910b57f13ded012e86bdcfb0532 (patch)
tree24e09d9f84dec336720cf393e156089ca2835791 /contrib/diff-highlight
parentInitial commit. (diff)
downloadgit-c8bae7493d2f2910b57f13ded012e86bdcfb0532.tar.xz
git-c8bae7493d2f2910b57f13ded012e86bdcfb0532.zip
Adding upstream version 1:2.39.2.upstream/1%2.39.2upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'contrib/diff-highlight')
-rw-r--r--contrib/diff-highlight/.gitignore2
-rw-r--r--contrib/diff-highlight/DiffHighlight.pm285
-rw-r--r--contrib/diff-highlight/Makefile23
-rw-r--r--contrib/diff-highlight/README223
-rw-r--r--contrib/diff-highlight/diff-highlight.perl8
-rw-r--r--contrib/diff-highlight/t/.gitignore2
-rw-r--r--contrib/diff-highlight/t/Makefile22
-rwxr-xr-xcontrib/diff-highlight/t/t9400-diff-highlight.sh341
8 files changed, 906 insertions, 0 deletions
diff --git a/contrib/diff-highlight/.gitignore b/contrib/diff-highlight/.gitignore
new file mode 100644
index 0000000..c074548
--- /dev/null
+++ b/contrib/diff-highlight/.gitignore
@@ -0,0 +1,2 @@
+shebang.perl
+diff-highlight
diff --git a/contrib/diff-highlight/DiffHighlight.pm b/contrib/diff-highlight/DiffHighlight.pm
new file mode 100644
index 0000000..376f577
--- /dev/null
+++ b/contrib/diff-highlight/DiffHighlight.pm
@@ -0,0 +1,285 @@
+package DiffHighlight;
+
+use 5.008;
+use warnings FATAL => 'all';
+use strict;
+
+# Use the correct value for both UNIX and Windows (/dev/null vs nul)
+use File::Spec;
+
+my $NULL = File::Spec->devnull();
+
+# Highlight by reversing foreground and background. You could do
+# other things like bold or underline if you prefer.
+my @OLD_HIGHLIGHT = (
+ color_config('color.diff-highlight.oldnormal'),
+ color_config('color.diff-highlight.oldhighlight', "\x1b[7m"),
+ color_config('color.diff-highlight.oldreset', "\x1b[27m")
+);
+my @NEW_HIGHLIGHT = (
+ color_config('color.diff-highlight.newnormal', $OLD_HIGHLIGHT[0]),
+ color_config('color.diff-highlight.newhighlight', $OLD_HIGHLIGHT[1]),
+ color_config('color.diff-highlight.newreset', $OLD_HIGHLIGHT[2])
+);
+
+my $RESET = "\x1b[m";
+my $COLOR = qr/\x1b\[[0-9;]*m/;
+my $BORING = qr/$COLOR|\s/;
+
+my @removed;
+my @added;
+my $in_hunk;
+my $graph_indent = 0;
+
+our $line_cb = sub { print @_ };
+our $flush_cb = sub { local $| = 1 };
+
+# Count the visible width of a string, excluding any terminal color sequences.
+sub visible_width {
+ local $_ = shift;
+ my $ret = 0;
+ while (length) {
+ if (s/^$COLOR//) {
+ # skip colors
+ } elsif (s/^.//) {
+ $ret++;
+ }
+ }
+ return $ret;
+}
+
+# Return a substring of $str, omitting $len visible characters from the
+# beginning, where terminal color sequences do not count as visible.
+sub visible_substr {
+ my ($str, $len) = @_;
+ while ($len > 0) {
+ if ($str =~ s/^$COLOR//) {
+ next
+ }
+ $str =~ s/^.//;
+ $len--;
+ }
+ return $str;
+}
+
+sub handle_line {
+ my $orig = shift;
+ local $_ = $orig;
+
+ # match a graph line that begins a commit
+ if (/^(?:$COLOR?\|$COLOR?[ ])* # zero or more leading "|" with space
+ $COLOR?\*$COLOR?[ ] # a "*" with its trailing space
+ (?:$COLOR?\|$COLOR?[ ])* # zero or more trailing "|"
+ [ ]* # trailing whitespace for merges
+ /x) {
+ my $graph_prefix = $&;
+
+ # We must flush before setting graph indent, since the
+ # new commit may be indented differently from what we
+ # queued.
+ flush();
+ $graph_indent = visible_width($graph_prefix);
+
+ } elsif ($graph_indent) {
+ if (length($_) < $graph_indent) {
+ $graph_indent = 0;
+ } else {
+ $_ = visible_substr($_, $graph_indent);
+ }
+ }
+
+ if (!$in_hunk) {
+ $line_cb->($orig);
+ $in_hunk = /^$COLOR*\@\@ /;
+ }
+ elsif (/^$COLOR*-/) {
+ push @removed, $orig;
+ }
+ elsif (/^$COLOR*\+/) {
+ push @added, $orig;
+ }
+ else {
+ flush();
+ $line_cb->($orig);
+ $in_hunk = /^$COLOR*[\@ ]/;
+ }
+
+ # Most of the time there is enough output to keep things streaming,
+ # but for something like "git log -Sfoo", you can get one early
+ # commit and then many seconds of nothing. We want to show
+ # that one commit as soon as possible.
+ #
+ # Since we can receive arbitrary input, there's no optimal
+ # place to flush. Flushing on a blank line is a heuristic that
+ # happens to match git-log output.
+ if (/^$/) {
+ $flush_cb->();
+ }
+}
+
+sub flush {
+ # Flush any queued hunk (this can happen when there is no trailing
+ # context in the final diff of the input).
+ show_hunk(\@removed, \@added);
+ @removed = ();
+ @added = ();
+}
+
+sub highlight_stdin {
+ while (<STDIN>) {
+ handle_line($_);
+ }
+ flush();
+}
+
+# Ideally we would feed the default as a human-readable color to
+# git-config as the fallback value. But diff-highlight does
+# not otherwise depend on git at all, and there are reports
+# of it being used in other settings. Let's handle our own
+# fallback, which means we will work even if git can't be run.
+sub color_config {
+ my ($key, $default) = @_;
+ my $s = `git config --get-color $key 2>$NULL`;
+ return length($s) ? $s : $default;
+}
+
+sub show_hunk {
+ my ($a, $b) = @_;
+
+ # If one side is empty, then there is nothing to compare or highlight.
+ if (!@$a || !@$b) {
+ $line_cb->(@$a, @$b);
+ return;
+ }
+
+ # If we have mismatched numbers of lines on each side, we could try to
+ # be clever and match up similar lines. But for now we are simple and
+ # stupid, and only handle multi-line hunks that remove and add the same
+ # number of lines.
+ if (@$a != @$b) {
+ $line_cb->(@$a, @$b);
+ return;
+ }
+
+ my @queue;
+ for (my $i = 0; $i < @$a; $i++) {
+ my ($rm, $add) = highlight_pair($a->[$i], $b->[$i]);
+ $line_cb->($rm);
+ push @queue, $add;
+ }
+ $line_cb->(@queue);
+}
+
+sub highlight_pair {
+ my @a = split_line(shift);
+ my @b = split_line(shift);
+
+ # Find common prefix, taking care to skip any ansi
+ # color codes.
+ my $seen_plusminus;
+ my ($pa, $pb) = (0, 0);
+ while ($pa < @a && $pb < @b) {
+ if ($a[$pa] =~ /$COLOR/) {
+ $pa++;
+ }
+ elsif ($b[$pb] =~ /$COLOR/) {
+ $pb++;
+ }
+ elsif ($a[$pa] eq $b[$pb]) {
+ $pa++;
+ $pb++;
+ }
+ elsif (!$seen_plusminus && $a[$pa] eq '-' && $b[$pb] eq '+') {
+ $seen_plusminus = 1;
+ $pa++;
+ $pb++;
+ }
+ else {
+ last;
+ }
+ }
+
+ # Find common suffix, ignoring colors.
+ my ($sa, $sb) = ($#a, $#b);
+ while ($sa >= $pa && $sb >= $pb) {
+ if ($a[$sa] =~ /$COLOR/) {
+ $sa--;
+ }
+ elsif ($b[$sb] =~ /$COLOR/) {
+ $sb--;
+ }
+ elsif ($a[$sa] eq $b[$sb]) {
+ $sa--;
+ $sb--;
+ }
+ else {
+ last;
+ }
+ }
+
+ if (is_pair_interesting(\@a, $pa, $sa, \@b, $pb, $sb)) {
+ return highlight_line(\@a, $pa, $sa, \@OLD_HIGHLIGHT),
+ highlight_line(\@b, $pb, $sb, \@NEW_HIGHLIGHT);
+ }
+ else {
+ return join('', @a),
+ join('', @b);
+ }
+}
+
+# we split either by $COLOR or by character. This has the side effect of
+# leaving in graph cruft. It works because the graph cruft does not contain "-"
+# or "+"
+sub split_line {
+ local $_ = shift;
+ return utf8::decode($_) ?
+ map { utf8::encode($_); $_ }
+ map { /$COLOR/ ? $_ : (split //) }
+ split /($COLOR+)/ :
+ map { /$COLOR/ ? $_ : (split //) }
+ split /($COLOR+)/;
+}
+
+sub highlight_line {
+ my ($line, $prefix, $suffix, $theme) = @_;
+
+ my $start = join('', @{$line}[0..($prefix-1)]);
+ my $mid = join('', @{$line}[$prefix..$suffix]);
+ my $end = join('', @{$line}[($suffix+1)..$#$line]);
+
+ # If we have a "normal" color specified, then take over the whole line.
+ # Otherwise, we try to just manipulate the highlighted bits.
+ if (defined $theme->[0]) {
+ s/$COLOR//g for ($start, $mid, $end);
+ chomp $end;
+ return join('',
+ $theme->[0], $start, $RESET,
+ $theme->[1], $mid, $RESET,
+ $theme->[0], $end, $RESET,
+ "\n"
+ );
+ } else {
+ return join('',
+ $start,
+ $theme->[1], $mid, $theme->[2],
+ $end
+ );
+ }
+}
+
+# Pairs are interesting to highlight only if we are going to end up
+# highlighting a subset (i.e., not the whole line). Otherwise, the highlighting
+# is just useless noise. We can detect this by finding either a matching prefix
+# or suffix (disregarding boring bits like whitespace and colorization).
+sub is_pair_interesting {
+ my ($a, $pa, $sa, $b, $pb, $sb) = @_;
+ my $prefix_a = join('', @$a[0..($pa-1)]);
+ my $prefix_b = join('', @$b[0..($pb-1)]);
+ my $suffix_a = join('', @$a[($sa+1)..$#$a]);
+ my $suffix_b = join('', @$b[($sb+1)..$#$b]);
+
+ return visible_substr($prefix_a, $graph_indent) !~ /^$COLOR*-$BORING*$/ ||
+ visible_substr($prefix_b, $graph_indent) !~ /^$COLOR*\+$BORING*$/ ||
+ $suffix_a !~ /^$BORING*$/ ||
+ $suffix_b !~ /^$BORING*$/;
+}
diff --git a/contrib/diff-highlight/Makefile b/contrib/diff-highlight/Makefile
new file mode 100644
index 0000000..f2be7cc
--- /dev/null
+++ b/contrib/diff-highlight/Makefile
@@ -0,0 +1,23 @@
+all: diff-highlight
+
+PERL_PATH = /usr/bin/perl
+-include ../../config.mak
+
+PERL_PATH_SQ = $(subst ','\'',$(PERL_PATH))
+
+diff-highlight: shebang.perl DiffHighlight.pm diff-highlight.perl
+ cat $^ >$@+
+ chmod +x $@+
+ mv $@+ $@
+
+shebang.perl: FORCE
+ @echo '#!$(PERL_PATH_SQ)' >$@+
+ @cmp $@+ $@ >/dev/null 2>/dev/null || mv $@+ $@
+
+test: all
+ $(MAKE) -C t
+
+clean:
+ $(RM) diff-highlight
+
+.PHONY: FORCE
diff --git a/contrib/diff-highlight/README b/contrib/diff-highlight/README
new file mode 100644
index 0000000..d4c2343
--- /dev/null
+++ b/contrib/diff-highlight/README
@@ -0,0 +1,223 @@
+diff-highlight
+==============
+
+Line oriented diffs are great for reviewing code, because for most
+hunks, you want to see the old and the new segments of code next to each
+other. Sometimes, though, when an old line and a new line are very
+similar, it's hard to immediately see the difference.
+
+You can use "--color-words" to highlight only the changed portions of
+lines. However, this can often be hard to read for code, as it loses
+the line structure, and you end up with oddly formatted bits.
+
+Instead, this script post-processes the line-oriented diff, finds pairs
+of lines, and highlights the differing segments. It's currently very
+simple and stupid about doing these tasks. In particular:
+
+ 1. It will only highlight hunks in which the number of removed and
+ added lines is the same, and it will pair lines within the hunk by
+ position (so the first removed line is compared to the first added
+ line, and so forth). This is simple and tends to work well in
+ practice. More complex changes don't highlight well, so we tend to
+ exclude them due to the "same number of removed and added lines"
+ restriction. Or even if we do try to highlight them, they end up
+ not highlighting because of our "don't highlight if the whole line
+ would be highlighted" rule.
+
+ 2. It will find the common prefix and suffix of two lines, and
+ consider everything in the middle to be "different". It could
+ instead do a real diff of the characters between the two lines and
+ find common subsequences. However, the point of the highlight is to
+ call attention to a certain area. Even if some small subset of the
+ highlighted area actually didn't change, that's OK. In practice it
+ ends up being more readable to just have a single blob on the line
+ showing the interesting bit.
+
+The goal of the script is therefore not to be exact about highlighting
+changes, but to call attention to areas of interest without being
+visually distracting. Non-diff lines and existing diff coloration is
+preserved; the intent is that the output should look exactly the same as
+the input, except for the occasional highlight.
+
+Use
+---
+
+You can try out the diff-highlight program with:
+
+---------------------------------------------
+git log -p --color | /path/to/diff-highlight
+---------------------------------------------
+
+If you want to use it all the time, drop it in your $PATH and put the
+following in your git configuration:
+
+---------------------------------------------
+[pager]
+ log = diff-highlight | less
+ show = diff-highlight | less
+ diff = diff-highlight | less
+---------------------------------------------
+
+
+Color Config
+------------
+
+You can configure the highlight colors and attributes using git's
+config. The colors for "old" and "new" lines can be specified
+independently. There are two "modes" of configuration:
+
+ 1. You can specify a "highlight" color and a matching "reset" color.
+ This will retain any existing colors in the diff, and apply the
+ "highlight" and "reset" colors before and after the highlighted
+ portion.
+
+ 2. You can specify a "normal" color and a "highlight" color. In this
+ case, existing colors are dropped from that line. The non-highlighted
+ bits of the line get the "normal" color, and the highlights get the
+ "highlight" color.
+
+If no "new" colors are specified, they default to the "old" colors. If
+no "old" colors are specified, the default is to reverse the foreground
+and background for highlighted portions.
+
+Examples:
+
+---------------------------------------------
+# Underline highlighted portions
+[color "diff-highlight"]
+oldHighlight = ul
+oldReset = noul
+---------------------------------------------
+
+---------------------------------------------
+# Varying background intensities
+[color "diff-highlight"]
+oldNormal = "black #f8cbcb"
+oldHighlight = "black #ffaaaa"
+newNormal = "black #cbeecb"
+newHighlight = "black #aaffaa"
+---------------------------------------------
+
+
+Using diff-highlight as a module
+--------------------------------
+
+If you want to pre- or post- process the highlighted lines as part of
+another perl script, you can use the DiffHighlight module. You can
+either "require" it or just cat the module together with your script (to
+avoid run-time dependencies).
+
+Your script may set up one or more of the following variables:
+
+ - $DiffHighlight::line_cb - this should point to a function which is
+ called whenever DiffHighlight has lines (which may contain
+ highlights) to output. The default function prints each line to
+ stdout. Note that the function may be called with multiple lines.
+
+ - $DiffHighlight::flush_cb - this should point to a function which
+ flushes the output (because DiffHighlight believes it has completed
+ processing a logical chunk of input). The default function flushes
+ stdout.
+
+The script may then feed lines, one at a time, to DiffHighlight::handle_line().
+When lines are done processing, they will be fed to $line_cb. Note that
+DiffHighlight may queue up many input lines (to analyze a whole hunk)
+before calling $line_cb. After providing all lines, call
+DiffHighlight::flush() to flush any unprocessed lines.
+
+If you just want to process stdin, DiffHighlight::highlight_stdin()
+is a convenience helper which will loop and flush for you.
+
+
+Bugs
+----
+
+Because diff-highlight relies on heuristics to guess which parts of
+changes are important, there are some cases where the highlighting is
+more distracting than useful. Fortunately, these cases are rare in
+practice, and when they do occur, the worst case is simply a little
+extra highlighting. This section documents some cases known to be
+sub-optimal, in case somebody feels like working on improving the
+heuristics.
+
+1. Two changes on the same line get highlighted in a blob. For example,
+ highlighting:
+
+----------------------------------------------
+-foo(buf, size);
++foo(obj->buf, obj->size);
+----------------------------------------------
+
+ yields (where the inside of "+{}" would be highlighted):
+
+----------------------------------------------
+-foo(buf, size);
++foo(+{obj->buf, obj->}size);
+----------------------------------------------
+
+ whereas a more semantically meaningful output would be:
+
+----------------------------------------------
+-foo(buf, size);
++foo(+{obj->}buf, +{obj->}size);
+----------------------------------------------
+
+ Note that doing this right would probably involve a set of
+ content-specific boundary patterns, similar to word-diff. Otherwise
+ you get junk like:
+
+-----------------------------------------------------
+-this line has some -{i}nt-{ere}sti-{ng} text on it
++this line has some +{fa}nt+{a}sti+{c} text on it
+-----------------------------------------------------
+
+ which is less readable than the current output.
+
+2. The multi-line matching assumes that lines in the pre- and post-image
+ match by position. This is often the case, but can be fooled when a
+ line is removed from the top and a new one added at the bottom (or
+ vice versa). Unless the lines in the middle are also changed, diffs
+ will show this as two hunks, and it will not get highlighted at all
+ (which is good). But if the lines in the middle are changed, the
+ highlighting can be misleading. Here's a pathological case:
+
+-----------------------------------------------------
+-one
+-two
+-three
+-four
++two 2
++three 3
++four 4
++five 5
+-----------------------------------------------------
+
+ which gets highlighted as:
+
+-----------------------------------------------------
+-one
+-t-{wo}
+-three
+-f-{our}
++two 2
++t+{hree 3}
++four 4
++f+{ive 5}
+-----------------------------------------------------
+
+ because it matches "two" to "three 3", and so forth. It would be
+ nicer as:
+
+-----------------------------------------------------
+-one
+-two
+-three
+-four
++two +{2}
++three +{3}
++four +{4}
++five 5
+-----------------------------------------------------
+
+ which would probably involve pre-matching the lines into pairs
+ according to some heuristic.
diff --git a/contrib/diff-highlight/diff-highlight.perl b/contrib/diff-highlight/diff-highlight.perl
new file mode 100644
index 0000000..9b3e9c1
--- /dev/null
+++ b/contrib/diff-highlight/diff-highlight.perl
@@ -0,0 +1,8 @@
+package main;
+
+# Some scripts may not realize that SIGPIPE is being ignored when launching the
+# pager--for instance scripts written in Python.
+$SIG{PIPE} = 'DEFAULT';
+
+DiffHighlight::highlight_stdin();
+exit 0;
diff --git a/contrib/diff-highlight/t/.gitignore b/contrib/diff-highlight/t/.gitignore
new file mode 100644
index 0000000..7dcbb23
--- /dev/null
+++ b/contrib/diff-highlight/t/.gitignore
@@ -0,0 +1,2 @@
+/trash directory*
+/test-results
diff --git a/contrib/diff-highlight/t/Makefile b/contrib/diff-highlight/t/Makefile
new file mode 100644
index 0000000..5ff5275
--- /dev/null
+++ b/contrib/diff-highlight/t/Makefile
@@ -0,0 +1,22 @@
+-include ../../../config.mak.autogen
+-include ../../../config.mak
+
+# copied from ../../t/Makefile
+SHELL_PATH ?= $(SHELL)
+SHELL_PATH_SQ = $(subst ','\'',$(SHELL_PATH))
+T = $(wildcard t[0-9][0-9][0-9][0-9]-*.sh)
+
+all: test
+test: $(T)
+
+.PHONY: help clean all test $(T)
+
+help:
+ @echo 'Run "$(MAKE) test" to launch test scripts'
+ @echo 'Run "$(MAKE) clean" to remove trash folders'
+
+$(T):
+ @echo "*** $@ ***"; '$(SHELL_PATH_SQ)' $@ $(GIT_TEST_OPTS)
+
+clean:
+ $(RM) -r 'trash directory'.*
diff --git a/contrib/diff-highlight/t/t9400-diff-highlight.sh b/contrib/diff-highlight/t/t9400-diff-highlight.sh
new file mode 100755
index 0000000..f6f5195
--- /dev/null
+++ b/contrib/diff-highlight/t/t9400-diff-highlight.sh
@@ -0,0 +1,341 @@
+#!/bin/sh
+
+test_description='Test diff-highlight'
+
+CURR_DIR=$(pwd)
+TEST_OUTPUT_DIRECTORY=$(pwd)
+TEST_DIRECTORY="$CURR_DIR"/../../../t
+DIFF_HIGHLIGHT="$CURR_DIR"/../diff-highlight
+
+CW="$(printf "\033[7m")" # white
+CR="$(printf "\033[27m")" # reset
+
+. "$TEST_DIRECTORY"/test-lib.sh
+
+if ! test_have_prereq PERL
+then
+ skip_all='skipping diff-highlight tests; perl not available'
+ test_done
+fi
+
+# dh_test is a test helper function which takes 3 file names as parameters. The
+# first 2 files are used to generate diff and commit output, which is then
+# piped through diff-highlight. The 3rd file should contain the expected output
+# of diff-highlight (minus the diff/commit header, ie. everything after and
+# including the first @@ line).
+dh_test () {
+ a="$1" b="$2" &&
+
+ cat >patch.exp &&
+
+ {
+ cat "$a" >file &&
+ git add file &&
+ git commit -m "Add a file" &&
+
+ cat "$b" >file &&
+ git diff file >diff.raw &&
+ git commit -a -m "Update a file" &&
+ git show >commit.raw
+ } >/dev/null &&
+
+ "$DIFF_HIGHLIGHT" <diff.raw | test_strip_patch_header >diff.act &&
+ "$DIFF_HIGHLIGHT" <commit.raw | test_strip_patch_header >commit.act &&
+ test_cmp patch.exp diff.act &&
+ test_cmp patch.exp commit.act
+}
+
+test_strip_patch_header () {
+ sed -n '/^@@/,$p' $*
+}
+
+# dh_test_setup_history generates a contrived graph such that we have at least
+# 1 nesting (E) and 2 nestings (F).
+#
+# A---B master
+# /
+# D---E---F branch
+#
+# git log --all --graph
+# * commit
+# | B
+# | * commit
+# | | F
+# * | commit
+# | | A
+# | * commit
+# |/
+# | E
+# * commit
+# D
+#
+dh_test_setup_history () {
+ echo file1 >file &&
+ git add file &&
+ test_tick &&
+ git commit -m "D" &&
+
+ git checkout -b branch &&
+ echo file2 >file &&
+ test_tick &&
+ git commit -a -m "E" &&
+
+ git checkout master &&
+ echo file2 >file &&
+ test_tick &&
+ git commit -a -m "A" &&
+
+ git checkout branch &&
+ echo file3 >file &&
+ test_tick &&
+ git commit -a -m "F" &&
+
+ git checkout master &&
+ echo file3 >file &&
+ test_tick &&
+ git commit -a -m "B"
+}
+
+left_trim () {
+ "$PERL_PATH" -pe 's/^\s+//'
+}
+
+trim_graph () {
+ # graphs start with * or |
+ # followed by a space or / or \
+ "$PERL_PATH" -pe 's@^((\*|\|)( |/|\\))+@@'
+}
+
+test_expect_success 'diff-highlight highlights the beginning of a line' '
+ cat >a <<-\EOF &&
+ aaa
+ bbb
+ ccc
+ EOF
+
+ cat >b <<-\EOF &&
+ aaa
+ 0bb
+ ccc
+ EOF
+
+ dh_test a b <<-EOF
+ @@ -1,3 +1,3 @@
+ aaa
+ -${CW}b${CR}bb
+ +${CW}0${CR}bb
+ ccc
+ EOF
+'
+
+test_expect_success 'diff-highlight highlights the end of a line' '
+ cat >a <<-\EOF &&
+ aaa
+ bbb
+ ccc
+ EOF
+
+ cat >b <<-\EOF &&
+ aaa
+ bb0
+ ccc
+ EOF
+
+ dh_test a b <<-EOF
+ @@ -1,3 +1,3 @@
+ aaa
+ -bb${CW}b${CR}
+ +bb${CW}0${CR}
+ ccc
+ EOF
+'
+
+test_expect_success 'diff-highlight highlights the middle of a line' '
+ cat >a <<-\EOF &&
+ aaa
+ bbb
+ ccc
+ EOF
+
+ cat >b <<-\EOF &&
+ aaa
+ b0b
+ ccc
+ EOF
+
+ dh_test a b <<-EOF
+ @@ -1,3 +1,3 @@
+ aaa
+ -b${CW}b${CR}b
+ +b${CW}0${CR}b
+ ccc
+ EOF
+'
+
+test_expect_success 'diff-highlight does not highlight whole line' '
+ cat >a <<-\EOF &&
+ aaa
+ bbb
+ ccc
+ EOF
+
+ cat >b <<-\EOF &&
+ aaa
+ 000
+ ccc
+ EOF
+
+ dh_test a b <<-EOF
+ @@ -1,3 +1,3 @@
+ aaa
+ -bbb
+ +000
+ ccc
+ EOF
+'
+
+test_expect_failure 'diff-highlight highlights mismatched hunk size' '
+ cat >a <<-\EOF &&
+ aaa
+ bbb
+ EOF
+
+ cat >b <<-\EOF &&
+ aaa
+ b0b
+ ccc
+ EOF
+
+ dh_test a b <<-EOF
+ @@ -1,3 +1,3 @@
+ aaa
+ -b${CW}b${CR}b
+ +b${CW}0${CR}b
+ +ccc
+ EOF
+'
+
+# These two code points share the same leading byte in UTF-8 representation;
+# a naive byte-wise diff would highlight only the second byte.
+#
+# - U+00f3 ("o" with acute)
+o_accent=$(printf '\303\263')
+# - U+00f8 ("o" with stroke)
+o_stroke=$(printf '\303\270')
+
+test_expect_success 'diff-highlight treats multibyte utf-8 as a unit' '
+ echo "unic${o_accent}de" >a &&
+ echo "unic${o_stroke}de" >b &&
+ dh_test a b <<-EOF
+ @@ -1 +1 @@
+ -unic${CW}${o_accent}${CR}de
+ +unic${CW}${o_stroke}${CR}de
+ EOF
+'
+
+# Unlike the UTF-8 above, these are combining code points which are meant
+# to modify the character preceding them:
+#
+# - U+0301 (combining acute accent)
+combine_accent=$(printf '\314\201')
+# - U+0302 (combining circumflex)
+combine_circum=$(printf '\314\202')
+
+test_expect_failure 'diff-highlight treats combining code points as a unit' '
+ echo "unico${combine_accent}de" >a &&
+ echo "unico${combine_circum}de" >b &&
+ dh_test a b <<-EOF
+ @@ -1 +1 @@
+ -unic${CW}o${combine_accent}${CR}de
+ +unic${CW}o${combine_circum}${CR}de
+ EOF
+'
+
+test_expect_success 'diff-highlight works with the --graph option' '
+ dh_test_setup_history &&
+
+ # date-order so that the commits are interleaved for both
+ # trim graph elements so we can do a diff
+ # trim leading space because our trim_graph is not perfect
+ git log --branches -p --date-order |
+ "$DIFF_HIGHLIGHT" | left_trim >graph.exp &&
+ git log --branches -p --date-order --graph |
+ "$DIFF_HIGHLIGHT" | trim_graph | left_trim >graph.act &&
+ test_cmp graph.exp graph.act
+'
+
+# Just reuse the previous graph test, but with --color. Our trimming
+# doesn't know about color, so just sanity check that something got
+# highlighted.
+test_expect_success 'diff-highlight works with color graph' '
+ git log --branches -p --date-order --graph --color |
+ "$DIFF_HIGHLIGHT" | trim_graph | left_trim >graph &&
+ grep "\[7m" graph
+'
+
+# Most combined diffs won't meet diff-highlight's line-number filter. So we
+# create one here where one side drops a line and the other modifies it. That
+# should result in a diff like:
+#
+# - modified content
+# ++resolved content
+#
+# which naively looks like one side added "+resolved".
+test_expect_success 'diff-highlight ignores combined diffs' '
+ echo "content" >file &&
+ git add file &&
+ git commit -m base &&
+
+ >file &&
+ git commit -am master &&
+
+ git checkout -b other HEAD^ &&
+ echo "modified content" >file &&
+ git commit -am other &&
+
+ test_must_fail git merge master &&
+ echo "resolved content" >file &&
+ git commit -am resolved &&
+
+ cat >expect <<-\EOF &&
+ --- a/file
+ +++ b/file
+ @@@ -1,1 -1,0 +1,1 @@@
+ - modified content
+ ++resolved content
+ EOF
+
+ git show -c | "$DIFF_HIGHLIGHT" >actual.raw &&
+ sed -n "/^---/,\$p" <actual.raw >actual &&
+ test_cmp expect actual
+'
+
+test_expect_success 'diff-highlight handles --graph with leading dash' '
+ cat >file <<-\EOF &&
+ before
+ the old line
+ -leading dash
+ EOF
+ git add file &&
+ git commit -m before &&
+
+ sed s/old/new/ <file >file.tmp &&
+ mv file.tmp file &&
+ git add file &&
+ git commit -m after &&
+
+ cat >expect <<-EOF &&
+ --- a/file
+ +++ b/file
+ @@ -1,3 +1,3 @@
+ before
+ -the ${CW}old${CR} line
+ +the ${CW}new${CR} line
+ -leading dash
+ EOF
+ git log --graph -p -1 | "$DIFF_HIGHLIGHT" >actual.raw &&
+ trim_graph <actual.raw | sed -n "/^---/,\$p" >actual &&
+ test_cmp expect actual
+'
+
+test_done