branch: optionally setup branch.*.merge from upstream local branches

"git branch" and "git checkout -b" now honor --track option even when
the upstream branch is local.  Previously --track was silently ignored
when forking from a local branch.  Also the command did not error out
when --track was explicitly asked for but the forked point specified
was not an existing branch (i.e. when there is no way to set up the
tracking configuration), but now it correctly does.

The configuration setting branch.autosetupmerge can now be set to
"always", which is equivalent to using --track from the command line.
Setting branch.autosetupmerge to "true" will retain the former behavior
of only setting up branch.*.merge for remote upstream branches.

Includes test cases for the new functionality.

Signed-off-by: Jay Soffian <jaysoffian@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

2 files changed, 45 insertions, 1 deletions

diff --git a/t/t3200-branch.sh b/t/t3200-branch.sh
index ef1eeb7d8a..900d814627 100755
--- a/t/t3200-branch.sh
+++ b/t/t3200-branch.sh
@@ -15,6 +15,9 @@ test_expect_success \
     'echo Hello > A &&
      git update-index --add A &&
      git-commit -m "Initial commit." &&
+     echo World >> A &&
+     git update-index --add A &&
+     git-commit -m "Second commit." &&
      HEAD=$(git rev-parse --verify HEAD)'
 
 test_expect_failure \
@@ -169,7 +172,9 @@ test_expect_success 'test overriding tracking setup via --no-track' \
      ! test "$(git config branch.my2.merge)" = refs/heads/master'
 
 test_expect_success 'no tracking without .fetch entries' \
-    'git branch --track my6 s &&
+    'git config branch.autosetupmerge true &&
+     git branch my6 s &&
+     git config branch.automsetupmerge false &&
      test -z "$(git config branch.my6.remote)" &&
      test -z "$(git config branch.my6.merge)"'
 
@@ -190,6 +195,21 @@ test_expect_success 'test deleting branch without config' \
     'git branch my7 s &&
      test "$(git branch -d my7 2>&1)" = "Deleted branch my7."'
 
+test_expect_success 'test --track without .fetch entries' \
+    'git branch --track my8 &&
+     test "$(git config branch.my8.remote)" &&
+     test "$(git config branch.my8.merge)"'
+
+test_expect_success \
+    'branch from non-branch HEAD w/autosetupmerge=always' \
+    'git config branch.autosetupmerge always &&
+     git branch my9 HEAD^ &&
+     git config branch.autosetupmerge false'
+
+test_expect_success \
+    'branch from non-branch HEAD w/--track causes failure' \
+    '!(git branch --track my10 HEAD^)'
+
 # Keep this test last, as it changes the current branch
 cat >expect <<EOF
 0000000000000000000000000000000000000000 $HEAD $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> 1117150200 +0000	branch: Created from master
diff --git a/t/t7201-co.sh b/t/t7201-co.sh
index 5492f21c7e..17cff8d515 100755
--- a/t/t7201-co.sh
+++ b/t/t7201-co.sh
@@ -263,4 +263,28 @@ test_expect_success 'checkout with ambiguous tag/branch names' '
 
 '
 
+test_expect_success \
+    'checkout w/--track sets up tracking' '
+    git config branch.autosetupmerge false &&
+    git checkout master &&
+    git checkout --track -b track1 &&
+    test "$(git config branch.track1.remote)" &&
+    test "$(git config branch.track1.merge)"'
+
+test_expect_success \
+    'checkout w/autosetupmerge=always sets up tracking' '
+    git config branch.autosetupmerge always &&
+    git checkout master &&
+    git checkout -b track2 &&
+    test "$(git config branch.track2.remote)" &&
+    test "$(git config branch.track2.merge)"
+    git config branch.autosetupmerge false'
+
+test_expect_success \
+    'checkout w/--track from non-branch HEAD fails' '
+    git checkout -b delete-me master &&
+    rm .git/refs/heads/delete-me &&
+    test refs/heads/delete-me = "$(git symbolic-ref HEAD)" &&
+    !(git checkout --track -b track)'
+
 test_done