diff: introduce diff.submodule configuration variable

diff --git a/t/t4041-diff-submodule-option.sh b/t/t4041-diff-submodule-option.sh
index 6c01d0c056e2608393ed16eea29dd45fc79d786c..876800ff246a999f06a66a8e6c36594a92fe08c1 100755 (executable)
--- a/t/t4041-diff-submodule-option.sh
+++ b/t/t4041-diff-submodule-option.sh
@@ -33,6 +33,7 @@ test_create_repo sm1 &&
 add_file . foo >/dev/null
 
 head1=$(add_file sm1 foo1 foo2)
+fullhead1=$(cd sm1; git rev-list --max-count=1 $head1)
 
 test_expect_success 'added submodule' "
        git add sm1 &&
@@ -43,6 +44,33 @@ EOF
        test_cmp expected actual
 "
 
+test_expect_success 'added submodule, set diff.submodule' "
+       git config diff.submodule log &&
+       git add sm1 &&
+       git diff --cached >actual &&
+       cat >expected <<-EOF &&
+Submodule sm1 0000000...$head1 (new submodule)
+EOF
+       git config --unset diff.submodule &&
+       test_cmp expected actual
+"
+
+test_expect_success '--submodule=short overrides diff.submodule' "
+       test_config diff.submodule log &&
+       git add sm1 &&
+       git diff --submodule=short --cached >actual &&
+       cat >expected <<-EOF &&
+diff --git a/sm1 b/sm1
+new file mode 160000
+index 0000000..a2c4dab
+--- /dev/null
++++ b/sm1
+@@ -0,0 +1 @@
++Subproject commit $fullhead1
+EOF
+       test_cmp expected actual
+"
+
 commit_file sm1 &&
 head2=$(add_file sm1 foo3)
 
@@ -73,7 +101,6 @@ EOF
        test_cmp expected actual
 "
 
-fullhead1=$(cd sm1; git rev-list --max-count=1 $head1)
 fullhead2=$(cd sm1; git rev-list --max-count=1 $head2)
 test_expect_success 'modified submodule(forward) --submodule=short' "
        git diff --submodule=short >actual &&