[PATCH v3 1/2] git-config support for diff.relative setting

[kelson@shysecurity.com]

By default, git-diff shows changes and pathnames relative to the 
repository root.
Setting diff.relative to "true" shows pathnames relative to the current 
directory
and excludes changes outside this directory.
---
  Documentation/diff-config.txt |  5 +++++
  diff.c                        |  8 ++++++++
  t/t4045-diff-relative.sh      | 21 +++++++++++++++++++++
  3 files changed, 34 insertions(+)

diff --git a/Documentation/diff-config.txt b/Documentation/diff-config.txt
index b001779..496e9b0 100644
--- a/Documentation/diff-config.txt
+++ b/Documentation/diff-config.txt
@@ -103,6 +103,11 @@ diff.orderfile::
      one shell glob pattern per line.
      Can be overridden by the '-O' option to linkgit:git-diff[1].

+diff.relative::
+    Show pathnames relative to the current directory and exclude
+    changes outside this directory; equivalent to the 'git diff'
+    option '--relative'.
+
  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 d1bd534..03697a9 100644
--- a/diff.c
+++ b/diff.c
@@ -223,6 +223,14 @@ int git_diff_ui_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 (git_color_config(var, value, cb) < 0)
          return -1;

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