[PATCH] config: Introduce --patience config variable

[Michal Privoznik <mprivozn@redhat.com>]

Some users like the patience diff more than the bare diff. However,
specifying the '--patience' argument every time diff is to be used
is impractical. Moreover, creating an alias doesn't play with other
tools nice, e.g. git-show; Therefore we need a configuration variable
to turn this on/off across whole git tools.
---
Please keep me CC'ed as I am not signed into list.

 Documentation/diff-config.txt |    3 +++
 diff.c                        |    9 +++++++++
 2 files changed, 12 insertions(+), 0 deletions(-)

diff --git a/Documentation/diff-config.txt b/Documentation/diff-config.txt
index 1aed79e..b72b2fd 100644
--- a/Documentation/diff-config.txt
+++ b/Documentation/diff-config.txt
@@ -86,6 +86,9 @@ diff.mnemonicprefix::
 diff.noprefix::
 	If set, 'git diff' does not show any source or destination prefix.
 
+diff.patience:
+    If set, 'git diff' will use patience algorithm.
+
 diff.renameLimit::
 	The number of files to consider when performing the copy/rename
 	detection; equivalent to the 'git diff' option '-l'.
diff --git a/diff.c b/diff.c
index a1c06b5..8940d00 100644
--- a/diff.c
+++ b/diff.c
@@ -33,6 +33,7 @@ static int diff_mnemonic_prefix;
 static int diff_no_prefix;
 static int diff_dirstat_permille_default = 30;
 static struct diff_options default_diff_options;
+static int diff_patience = 0;
 
 static char diff_colors[][COLOR_MAXLEN] = {
 	GIT_COLOR_RESET,
@@ -212,6 +213,11 @@ int git_diff_basic_config(const char *var, const char *value, void *cb)
 	if (!prefixcmp(var, "submodule."))
 		return parse_submodule_config_option(var, value);
 
+    if (!strcmp(var, "diff.patience")) {
+		diff_patience = git_config_bool(var, value);
+		return 0;
+    }
+
 	return git_default_config(var, value, cb);
 }
 
@@ -3202,6 +3208,9 @@ int diff_setup_done(struct diff_options *options)
 		DIFF_OPT_SET(options, EXIT_WITH_STATUS);
 	}
 
+    if (diff_patience)
+		DIFF_XDL_SET(options, PATIENCE_DIFF);
+
 	return 0;
 }
 
-- 
1.7.3.4