Merge branch 'tc/merge-default-to-upstream-leakfix' into jch

Leakfix.

* tc/merge-default-to-upstream-leakfix:
  merge: fix leak with merge.defaultToUpstream

diff --cc builtin/merge.c
Simple merge

diff --cc t/t7600-merge.sh
index 7f2a1db16da0c381478e52286cf017a3a9d2ff32,b3a2164e0836cd57b1ecf84aafcde9f8c5592e8a..e31d261f9d3d7f8c1a0c4072d051203e0d8bc879
--- 1/t/t7600-merge.sh
--- 2/t/t7600-merge.sh
+++ b/t/t7600-merge.sh
@@@ -1163,7 -1162,24 +1163,24 @@@ test_expect_success 'merge suggests mat
  test_expect_success 'suggested names are not ambiguous' '
        git update-ref refs/heads/origin/not-local HEAD &&
        test_must_fail git merge not-local 2>stderr &&
 -      grep remotes/origin/not-local stderr
 +      test_grep remotes/origin/not-local stderr
  '
  
+ test_expect_success 'merge with no argument defaults to upstream' '
+       test_when_finished "rm -rf upstream downstream" &&
+       git init upstream &&
+       (
+               cd upstream &&
+               test_commit one &&
+               test_commit two
+       ) &&
+       git clone upstream downstream &&
+       (
+               cd downstream &&
+               git reset --hard HEAD^ &&
+               git merge &&
+               test_cmp_rev origin/main HEAD
+       )
+ '
+ 
  test_done