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Merge branch 'ad/blame-diff-algorithm' into seen
"git blame" learns "--diff-algorithm=<algo>" option. * ad/blame-diff-algorithm: blame: make diff algorithm configurable
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‎Documentation/diff-algorithm-option.adoc‎

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`--diff-algorithm=(patience|minimal|histogram|myers)`::
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Choose a diff algorithm. The variants are as follows:
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+
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--
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`default`;;
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`myers`;;
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The basic greedy diff algorithm. Currently, this is the default.
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`minimal`;;
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Spend extra time to make sure the smallest possible diff is
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produced.
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`patience`;;
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Use "patience diff" algorithm when generating patches.
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`histogram`;;
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This algorithm extends the patience algorithm to "support
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low-occurrence common elements".
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--
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+
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For instance, if you configured the `diff.algorithm` variable to a
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non-default value and want to use the default one, then you
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have to use `--diff-algorithm=default` option.

‎Documentation/diff-options.adoc‎

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@@ -197,26 +197,7 @@ and starts with _<text>_, this algorithm attempts to prevent it from
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appearing as a deletion or addition in the output. It uses the "patience
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diff" algorithm internally.
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`--diff-algorithm=(patience|minimal|histogram|myers)`::
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Choose a diff algorithm. The variants are as follows:
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+
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--
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`default`;;
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`myers`;;
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The basic greedy diff algorithm. Currently, this is the default.
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`minimal`;;
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Spend extra time to make sure the smallest possible diff is
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produced.
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`patience`;;
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Use "patience diff" algorithm when generating patches.
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`histogram`;;
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This algorithm extends the patience algorithm to "support
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low-occurrence common elements".
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--
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+
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For instance, if you configured the `diff.algorithm` variable to a
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non-default value and want to use the default one, then you
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have to use `--diff-algorithm=default` option.
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include::diff-algorithm-option.adoc[]
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`--stat[=<width>[,<name-width>[,<count>]]]`::
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Generate a diffstat. By default, as much space as necessary

‎Documentation/git-blame.adoc‎

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@@ -85,6 +85,8 @@ include::blame-options.adoc[]
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Ignore whitespace when comparing the parent's version and
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the child's to find where the lines came from.
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include::diff-algorithm-option.adoc[]
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--abbrev=<n>::
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Instead of using the default 7+1 hexadecimal digits as the
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abbreviated object name, use <m>+1 digits, where <m> is at

‎builtin/blame.c‎

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Original file line numberDiff line numberDiff line change
@@ -779,6 +779,19 @@ static int git_blame_config(const char *var, const char *value,
779779
}
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}
781781

782+
if (!strcmp(var, "diff.algorithm")) {
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long diff_algorithm;
784+
if (!value)
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return config_error_nonbool(var);
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diff_algorithm = parse_algorithm_value(value);
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if (diff_algorithm < 0)
788+
return error(_("unknown value for config '%s': %s"),
789+
var, value);
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xdl_opts &= ~XDF_DIFF_ALGORITHM_MASK;
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xdl_opts |= diff_algorithm;
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return 0;
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}
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782795
if (git_diff_heuristic_config(var, value, cb) < 0)
783796
return -1;
784797
if (userdiff_config(var, value) < 0)
@@ -824,6 +837,38 @@ static int blame_move_callback(const struct option *option, const char *arg, int
824837
return 0;
825838
}
826839

840+
static int blame_diff_algorithm_minimal(const struct option *option,
841+
const char *arg, int unset)
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{
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int *opt = option->value;
844+
845+
BUG_ON_OPT_NEG(unset);
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BUG_ON_OPT_ARG(arg);
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848+
*opt &= ~XDF_DIFF_ALGORITHM_MASK;
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*opt |= XDF_NEED_MINIMAL;
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851+
return 0;
852+
}
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854+
static int blame_diff_algorithm_callback(const struct option *option,
855+
const char *arg, int unset)
856+
{
857+
int *opt = option->value;
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long value = parse_algorithm_value(arg);
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860+
BUG_ON_OPT_NEG(unset);
861+
862+
if (value < 0)
863+
return error(_("option diff-algorithm accepts \"myers\", "
864+
"\"minimal\", \"patience\" and \"histogram\""));
865+
866+
*opt &= ~(XDF_NEED_MINIMAL | XDF_DIFF_ALGORITHM_MASK);
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*opt |= value;
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869+
return 0;
870+
}
871+
827872
static int is_a_rev(const char *name)
828873
{
829874
struct object_id oid;
@@ -915,11 +960,17 @@ int cmd_blame(int argc,
915960
OPT_BIT('s', NULL, &output_option, N_("suppress author name and timestamp (Default: off)"), OUTPUT_NO_AUTHOR),
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OPT_BIT('e', "show-email", &output_option, N_("show author email instead of name (Default: off)"), OUTPUT_SHOW_EMAIL),
917962
OPT_BIT('w', NULL, &xdl_opts, N_("ignore whitespace differences"), XDF_IGNORE_WHITESPACE),
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OPT_CALLBACK_F(0, "diff-algorithm", &xdl_opts, N_("<algorithm>"),
964+
N_("choose a diff algorithm"),
965+
PARSE_OPT_NONEG, blame_diff_algorithm_callback),
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OPT_STRING_LIST(0, "ignore-rev", &ignore_rev_list, N_("rev"), N_("ignore <rev> when blaming")),
919967
OPT_STRING_LIST(0, "ignore-revs-file", &ignore_revs_file_list, N_("file"), N_("ignore revisions from <file>")),
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OPT_BIT(0, "color-lines", &output_option, N_("color redundant metadata from previous line differently"), OUTPUT_COLOR_LINE),
921969
OPT_BIT(0, "color-by-age", &output_option, N_("color lines by age"), OUTPUT_SHOW_AGE_WITH_COLOR),
922-
OPT_BIT(0, "minimal", &xdl_opts, N_("spend extra cycles to find better match"), XDF_NEED_MINIMAL),
970+
OPT_CALLBACK_F(0, "minimal", &xdl_opts, NULL,
971+
N_("spend extra cycles to find better match"),
972+
PARSE_OPT_NONEG | PARSE_OPT_NOARG,
973+
blame_diff_algorithm_minimal),
923974
OPT_STRING('S', NULL, &revs_file, N_("file"), N_("use revisions from <file> instead of calling git-rev-list")),
924975
OPT_STRING(0, "contents", &contents_from, N_("file"), N_("use <file>'s contents as the final image")),
925976
OPT_CALLBACK_F('C', NULL, &opt, N_("score"), N_("find line copies within and across files"), PARSE_OPT_OPTARG, blame_copy_callback),

‎t/meson.build‎

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@@ -960,6 +960,7 @@ integration_tests = [
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't8012-blame-colors.sh',
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't8013-blame-ignore-revs.sh',
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't8014-blame-ignore-fuzzy.sh',
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't8015-blame-diff-algorithm.sh',
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't8020-last-modified.sh',
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't9001-send-email.sh',
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't9002-column.sh',

‎t/t8015-blame-diff-algorithm.sh‎

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#!/bin/sh
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test_description='git blame with specific diff algorithm'
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. ./test-lib.sh
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test_expect_success setup '
8+
cat >file.c <<-\EOF &&
9+
int f(int x, int y)
10+
{
11+
if (x == 0)
12+
{
13+
return y;
14+
}
15+
return x;
16+
}
17+
18+
int g(size_t u)
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{
20+
while (u < 30)
21+
{
22+
u++;
23+
}
24+
return u;
25+
}
26+
EOF
27+
test_write_lines x x x x >file.txt &&
28+
git add file.c file.txt &&
29+
GIT_AUTHOR_NAME=Commit_1 git commit -m Commit_1 &&
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cat >file.c <<-\EOF &&
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int g(size_t u)
33+
{
34+
while (u < 30)
35+
{
36+
u++;
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}
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return u;
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}
40+
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int h(int x, int y, int z)
42+
{
43+
if (z == 0)
44+
{
45+
return x;
46+
}
47+
return y;
48+
}
49+
EOF
50+
test_write_lines x x x A B C D x E F G >file.txt &&
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git add file.c file.txt &&
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GIT_AUTHOR_NAME=Commit_2 git commit -m Commit_2
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'
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55+
test_expect_success 'blame uses Myers diff algorithm by default for now' '
56+
cat >expected <<-\EOF &&
57+
Commit_2 int g(size_t u)
58+
Commit_1 {
59+
Commit_2 while (u < 30)
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Commit_1 {
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Commit_2 u++;
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Commit_1 }
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Commit_2 return u;
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Commit_1 }
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Commit_1
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Commit_2 int h(int x, int y, int z)
67+
Commit_1 {
68+
Commit_2 if (z == 0)
69+
Commit_1 {
70+
Commit_2 return x;
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Commit_1 }
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Commit_2 return y;
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Commit_1 }
74+
EOF
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76+
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git blame file.c | \
78+
sed -e "s/^[^ ]* (\([^ ]*\) [^)]*)/\1/g" | \
79+
sed -e "s/ *$//g" > actual &&
80+
test_cmp expected actual
81+
'
82+
83+
test_expect_success 'blame honors --diff-algorithm option' '
84+
cat >expected <<-\EOF &&
85+
Commit_1 int g(size_t u)
86+
Commit_1 {
87+
Commit_1 while (u < 30)
88+
Commit_1 {
89+
Commit_1 u++;
90+
Commit_1 }
91+
Commit_1 return u;
92+
Commit_1 }
93+
Commit_2
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Commit_2 int h(int x, int y, int z)
95+
Commit_2 {
96+
Commit_2 if (z == 0)
97+
Commit_2 {
98+
Commit_2 return x;
99+
Commit_2 }
100+
Commit_2 return y;
101+
Commit_2 }
102+
EOF
103+
104+
git blame file.c --diff-algorithm histogram | \
105+
sed -e "s/^[^ ]* (\([^ ]*\) [^)]*)/\1/g" | \
106+
sed -e "s/ *$//g" > actual &&
107+
test_cmp expected actual
108+
'
109+
110+
test_expect_success 'blame honors diff.algorithm config variable' '
111+
cat >expected <<-\EOF &&
112+
Commit_1 int g(size_t u)
113+
Commit_1 {
114+
Commit_1 while (u < 30)
115+
Commit_1 {
116+
Commit_1 u++;
117+
Commit_1 }
118+
Commit_1 return u;
119+
Commit_1 }
120+
Commit_2
121+
Commit_2 int h(int x, int y, int z)
122+
Commit_2 {
123+
Commit_2 if (z == 0)
124+
Commit_2 {
125+
Commit_2 return x;
126+
Commit_2 }
127+
Commit_2 return y;
128+
Commit_2 }
129+
EOF
130+
131+
git config diff.algorithm histogram &&
132+
git blame file.c | \
133+
sed -e "s/^[^ ]* (\([^ ]*\) [^)]*)/\1/g" | \
134+
sed -e "s/ *$//g" > actual &&
135+
test_cmp expected actual
136+
'
137+
138+
test_expect_success 'blame gives priority to --diff-algorithm over diff.algorithm' '
139+
cat >expected <<-\EOF &&
140+
Commit_1 int g(size_t u)
141+
Commit_1 {
142+
Commit_1 while (u < 30)
143+
Commit_1 {
144+
Commit_1 u++;
145+
Commit_1 }
146+
Commit_1 return u;
147+
Commit_1 }
148+
Commit_2
149+
Commit_2 int h(int x, int y, int z)
150+
Commit_2 {
151+
Commit_2 if (z == 0)
152+
Commit_2 {
153+
Commit_2 return x;
154+
Commit_2 }
155+
Commit_2 return y;
156+
Commit_2 }
157+
EOF
158+
159+
git config diff.algorithm myers &&
160+
git blame file.c --diff-algorithm histogram | \
161+
sed -e "s/^[^ ]* (\([^ ]*\) [^)]*)/\1/g" | \
162+
sed -e "s/ *$//g" > actual &&
163+
test_cmp expected actual
164+
'
165+
test_expect_success 'blame honors --minimal option' '
166+
cat >expected <<-\EOF &&
167+
Commit_1 x
168+
Commit_1 x
169+
Commit_1 x
170+
Commit_2 A
171+
Commit_2 B
172+
Commit_2 C
173+
Commit_2 D
174+
Commit_1 x
175+
Commit_2 E
176+
Commit_2 F
177+
Commit_2 G
178+
EOF
179+
180+
git blame file.txt --minimal | \
181+
sed -e "s/^[^ ]* (\([^ ]*\) [^)]*)/\1/g" > actual &&
182+
test_cmp expected actual
183+
'
184+
185+
test_expect_success 'blame respects the order of diff options' '
186+
cat >expected <<-\EOF &&
187+
Commit_1 x
188+
Commit_1 x
189+
Commit_1 x
190+
Commit_2 A
191+
Commit_2 B
192+
Commit_2 C
193+
Commit_2 D
194+
Commit_2 x
195+
Commit_2 E
196+
Commit_2 F
197+
Commit_2 G
198+
EOF
199+
200+
git blame file.txt --minimal --diff-algorithm myers | \
201+
sed -e "s/^[^ ]* (\([^ ]*\) [^)]*)/\1/g" > actual &&
202+
test_cmp expected actual
203+
'
204+
205+
206+
test_done

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