[PATCH] added git-config support for diff.relative setting

[Kelson <kelson@shysecurity.com>]

By default, git-diff shows changes and pathnames relative to the 
repository root.
Setting the diff.relative config option to "true" shows pathnames 
relative to
the current directory and excludes changes outside this directory.
---
  Documentation/diff-config.txt |  6 ++++++
  diff.c                        |  8 ++++++++
  t/t4045-diff-relative.sh      | 21 +++++++++++++++++++++
  3 files changed, 35 insertions(+)

diff --git a/Documentation/diff-config.txt b/Documentation/diff-config.txt
index b001779..10f183f 100644
--- a/Documentation/diff-config.txt
+++ b/Documentation/diff-config.txt
@@ -182,3 +182,9 @@ diff.algorithm::
  	low-occurrence common elements".
  --
  +
+
+diff.relative::
+	By default, linkgit:git-diff[1] shows changes and pathnames
+	relative to the repository root. Setting this variable to
+	`true` shows pathnames relative to the current directory and
+	excludes changes outside this directory.
diff --git a/diff.c b/diff.c
index d1bd534..22daa2f 100644
--- a/diff.c
+++ b/diff.c
@@ -270,6 +270,14 @@ int git_diff_basic_config(const char *var, const 
char *value, void *cb)
  		return 0;
  	}

+	if (!strcmp(var, "diff.relative")) {
+		if (git_config_bool(var, value))
+			DIFF_OPT_SET(&default_diff_options, RELATIVE_NAME);
+		else
+			DIFF_OPT_CLR(&default_diff_options, RELATIVE_NAME);
+		return 0;
+	}
+
  	if (starts_with(var, "submodule."))
  		return parse_submodule_config_option(var, value);

diff --git a/t/t4045-diff-relative.sh b/t/t4045-diff-relative.sh
index 3950f50..8c8fe0b 100755
--- a/t/t4045-diff-relative.sh
+++ b/t/t4045-diff-relative.sh
@@ -29,6 +29,23 @@ test_expect_success "-p $*" "
  "
  }

+check_config() {
+expect=$1; shift
+cat >expected <<EOF
+diff --git a/$expect b/$expect
+new file mode 100644
+index 0000000..25c05ef
+--- /dev/null
++++ b/$expect
+@@ -0,0 +1 @@
++other content
+EOF
+test_expect_success "git-config diff.relative=true in $1" "
+	(cd $1; git -c diff.relative=true diff -p HEAD^ >../actual) &&
+	test_cmp expected actual
+"
+}
+
  check_numstat() {
  expect=$1; shift
  cat >expected <<EOF
@@ -69,5 +86,9 @@ for type in diff numstat stat raw; do
  	check_$type file2 --relative=subdir
  	check_$type dir/file2 --relative=sub
  done
+for type in config; do
+	check_$type file2 subdir/
+	check_$type file2 subdir
+done

  test_done
-- 
1.9.1