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Junio C Hamano  committed b51c9a2 Merge with conflicts

Merge branch 'mp/diff-algo-config' into pu

Add diff.algorithm configuration so that the user does not type
"diff --histogram".

Looking better; may want tests to protect it from future breakages,
but otherwise it looks ready for 'next'.

Expecting a follow-up to add tests.

* 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

Conflicts:
Documentation/diff-config.txt

  • Participants
  • Parent commits e024abc, 07924d4
  • Branches pu

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Files changed (6)

File Documentation/diff-config.txt

 	that a corresponding difftool.<tool>.cmd variable is defined.
 
 include::mergetools-diff.txt[]
+
+diff.algorithm::
+	Choose a diff algorithm.  The variants are as follows:
++
+--
+`default`, `myers`;;
+	The basic greedy diff algorithm. Currently, this is the default.
+`minimal`;;
+	Spend extra time to make sure the smallest possible diff is
+	produced.
+`patience`;;
+	Use "patience diff" algorithm when generating patches.
+`histogram`;;
+	This algorithm extends the patience algorithm to "support
+	low-occurrence common elements".
+--
++

File Documentation/diff-options.txt

 --histogram::
 	Generate a diff using the "histogram diff" algorithm.
 
+--diff-algorithm={patience|minimal|histogram|myers}::
+	Choose a diff algorithm. The variants are as follows:
++
+--
+`default`, `myers`;;
+	The basic greedy diff algorithm. Currently, this is the default.
+`minimal`;;
+	Spend extra time to make sure the smallest possible diff is
+	produced.
+`patience`;;
+	Use "patience diff" algorithm when generating patches.
+`histogram`;;
+	This algorithm extends the patience algorithm to "support
+	low-occurrence common elements".
+--
++
+For instance, if you configured diff.algorithm variable to a
+non-default value and want to use the default one, then you
+have to use `--diff-algorithm=default` option.
+
 --stat[=<width>[,<name-width>[,<count>]]]::
 	Generate a diffstat. By default, as much space as necessary
 	will be used for the filename part, and the rest for the graph

File contrib/completion/git-completion.bash

 	__gitcomp_nl "$(__git_refs)"
 }
 
+__git_diff_algorithms="myers minimal patience histogram"
+
 __git_diff_common_options="--stat --numstat --shortstat --summary
 			--patch-with-stat --name-only --name-status --color
 			--no-color --color-words --no-renames --check
 			--no-ext-diff
 			--no-prefix --src-prefix= --dst-prefix=
 			--inter-hunk-context=
-			--patience
+			--patience --histogram --minimal
 			--raw
 			--dirstat --dirstat= --dirstat-by-file
 			--dirstat-by-file= --cumulative
+			--diff-algorithm=
 "
 
 _git_diff ()
 	__git_has_doubledash && return
 
 	case "$cur" in
+	--diff-algorithm=*)
+		__gitcomp "$__git_diff_algorithms" "" "${cur##--diff-algorithm=}"
+		return
+		;;
 	--*)
 		__gitcomp "--cached --staged --pickaxe-all --pickaxe-regex
 			--base --ours --theirs --no-index
 		diff.suppressBlankEmpty
 		diff.tool
 		diff.wordRegex
+		diff.algorithm
 		difftool.
 		difftool.prompt
 		fetch.recurseSubmodules
 			" "" "${cur#*=}"
 		return
 		;;
+	--diff-algorithm=*)
+		__gitcomp "$__git_diff_algorithms" "" "${cur##--diff-algorithm=}"
+		return
+		;;
 	--*)
 		__gitcomp "--pretty= --format= --abbrev-commit --oneline
 			$__git_diff_common_options
 static int diff_stat_graph_width;
 static int diff_dirstat_permille_default = 30;
 static struct diff_options default_diff_options;
+static long diff_algorithm;
 
 static char diff_colors[][COLOR_MAXLEN] = {
 	GIT_COLOR_RESET,
 	return git_config_bool(var,value) ? DIFF_DETECT_RENAME : 0;
 }
 
+long parse_algorithm_value(const char *value)
+{
+	if (!value)
+		return -1;
+	else if (!strcasecmp(value, "myers") || !strcasecmp(value, "default"))
+		return 0;
+	else if (!strcasecmp(value, "minimal"))
+		return XDF_NEED_MINIMAL;
+	else if (!strcasecmp(value, "patience"))
+		return XDF_PATIENCE_DIFF;
+	else if (!strcasecmp(value, "histogram"))
+		return XDF_HISTOGRAM_DIFF;
+	return -1;
+}
+
 /*
  * These are to give UI layer defaults.
  * The core-level commands such as git-diff-files should
 		return 0;
 	}
 
+	if (!strcmp(var, "diff.algorithm")) {
+		diff_algorithm = parse_algorithm_value(value);
+		if (diff_algorithm < 0)
+			return -1;
+		return 0;
+	}
+
 	if (git_color_config(var, value, cb) < 0)
 		return -1;
 
 	options->add_remove = diff_addremove;
 	options->use_color = diff_use_color_default;
 	options->detect_rename = diff_detect_rename_default;
+	options->xdl_opts |= diff_algorithm;
 
 	if (diff_no_prefix) {
 		options->a_prefix = options->b_prefix = "";
 		options->xdl_opts = DIFF_WITH_ALG(options, PATIENCE_DIFF);
 	else if (!strcmp(arg, "--histogram"))
 		options->xdl_opts = DIFF_WITH_ALG(options, HISTOGRAM_DIFF);
+	else if (!prefixcmp(arg, "--diff-algorithm=")) {
+		long value = parse_algorithm_value(arg+17);
+		if (value < 0)
+			return error("option diff-algorithm accepts \"myers\", "
+				     "\"minimal\", \"patience\" and \"histogram\"");
+		/* clear out previous settings */
+		DIFF_XDL_CLR(options, NEED_MINIMAL);
+		options->xdl_opts &= ~XDF_DIFF_ALGORITHM_MASK;
+		options->xdl_opts |= value;
+	}
 
 	/* flags options */
 	else if (!strcmp(arg, "--binary")) {
 
 extern int parse_rename_score(const char **cp_p);
 
+extern long parse_algorithm_value(const char *value);
+
 extern int print_stat_summary(FILE *fp, int files,
 			      int insertions, int deletions);
 extern void setup_diff_pager(struct diff_options *);

File merge-recursive.c

 		o->xdl_opts = DIFF_WITH_ALG(o, PATIENCE_DIFF);
 	else if (!strcmp(s, "histogram"))
 		o->xdl_opts = DIFF_WITH_ALG(o, HISTOGRAM_DIFF);
+	else if (!strcmp(s, "diff-algorithm=")) {
+		long value = parse_algorithm_value(s+15);
+		if (value < 0)
+			return -1;
+		/* clear out previous settings */
+		DIFF_XDL_CLR(o, NEED_MINIMAL);
+		o->xdl_opts &= ~XDF_DIFF_ALGORITHM_MASK;
+		o->xdl_opts |= value;
+	}
 	else if (!strcmp(s, "ignore-space-change"))
 		o->xdl_opts |= XDF_IGNORE_WHITESPACE_CHANGE;
 	else if (!strcmp(s, "ignore-all-space"))