Bibisect: mergeranges: Allow merge into existing branch

This commit adds functionality to the 'mergeranges' script. It give us
the ability to add bibisect commits to an existing branch in a
repository. Previously, we could only start the merge process by
creating a new branch.

Change-Id: I436ac6490de6993ed57135b72c793f46150f7b07
Reviewed-on: https://gerrit.libreoffice.org/6921
Reviewed-by: Björn Michaelsen <bjoern.michaelsen@canonical.com>
Tested-by: Björn Michaelsen <bjoern.michaelsen@canonical.com>

1 files changed, 15 insertions, 2 deletions

diff --git a/bibisect/mergeranges b/bibisect/mergeranges
index 5d9b14a1..b35e9514 100755
--- a/bibisect/mergeranges
+++ b/bibisect/mergeranges
@@ -7,8 +7,22 @@ def justrunit(arglist):
     print(subprocess.check_output(arglist).decode('utf-8'))
 
 def init_branch(startpoint):
-    justrunit(['git', 'checkout', '-b', 'mergeranges', startpoint])
+    global initBranch, branchName
 
+    try:
+        justrunit(['git', 'checkout', branchName])
+    except CalledProcessError as e:
+        # If the branch does not exist, we need to create it.
+        justrunit(['git', 'checkout', '-b', branchName, startpoint])
+        print("Creating branch " + branchName)
+    else:
+        # If the branch already existed, we want to cherry-pick the
+        # 'startpoint' commit.
+        cherry_pick_theirs(startpoint)
+
+    initBranch = True
+
+# Pull a commit into the git repository.
 def cherry_pick_theirs(revision):
     try:
         justrunit(['git', 'rm', '-rf', '.'])
@@ -26,6 +40,5 @@ for line in open(sys.argv[1]).readlines():
     for revision in revisions:
         if not initBranch:
             init_branch(revision)
-            initBranch = True
         else:
             cherry_pick_theirs(revision)