git-commit: Allow to amend a merge commit that does not change the tree

diff --git a/t/t7501-commit.sh b/t/t7501-commit.sh
index 9dba104b1f8bf9125f1a947a2fd115b684a94095..2e7bcb016ac94f150423446b2fbce2d61eb7bced 100755 (executable)
--- a/t/t7501-commit.sh
+++ b/t/t7501-commit.sh
@@ -79,7 +79,8 @@ test_expect_success \
 
 cat >editor <<\EOF
 #!/bin/sh
-sed -i -e "s/a file/an amend commit/g" $1
+sed -e "s/a file/an amend commit/g" < $1 > $1-
+mv $1- $1
 EOF
 chmod 755 editor
 
@@ -98,7 +99,8 @@ test_expect_success \
 
 cat >editor <<\EOF
 #!/bin/sh
-sed -i -e "s/amend/older/g" $1
+sed -e "s/amend/older/g"  < $1 > $1-
+mv $1- $1
 EOF
 chmod 755 editor
 
@@ -242,4 +244,36 @@ test_expect_success 'multiple -m' '
 
 '
 
+test_expect_success 'same tree (single parent)' '
+
+       if git commit -m empty
+       then
+               echo oops -- should have complained
+               false
+       else
+               : happy
+       fi
+
+'
+
+test_expect_success 'same tree (merge and amend merge)' '
+
+       git checkout -b side HEAD^ &&
+       echo zero >zero &&
+       git add zero &&
+       git commit -m "add zero" &&
+       git checkout master &&
+
+       git merge -s ours side -m "empty ok" &&
+       git diff HEAD^ HEAD >actual &&
+       : >expected &&
+       diff -u expected actual &&
+
+       git commit --amend -m "empty really ok" &&
+       git diff HEAD^ HEAD >actual &&
+       : >expected &&
+       diff -u expected actual
+
+'
+
 test_done