Added repo cherry-pick command
It is undesired to have the same Change-Id:-line for two separate
commits, and when cherry-picking, the user must manually change it.
If this is not done, bad things may happen (such as when the user
is uploading the cherry-picked commit to Gerrit, it will instead
see it as a new patch-set for the original change, or worse).
repo cherry-pick works the same was as git cherry-pick, except that
it replaces the Change-Id with a new one and adds a reference
back to the commit from where it was picked.
On failures (when git can not successfully apply the cherry-picked
commit), instructions will be written to the user.
Change-Id: I5a38b89839f91848fad43386d43cae2f6cdabf83
diff --git a/subcmds/cherry_pick.py b/subcmds/cherry_pick.py
new file mode 100644
index 0000000..8da3a75
--- /dev/null
+++ b/subcmds/cherry_pick.py
@@ -0,0 +1,114 @@
+#
+# Copyright (C) 2010 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import sys, re, string, random, os
+from command import Command
+from git_command import GitCommand
+
+CHANGE_ID_RE = re.compile(r'^\s*Change-Id: I([0-9a-f]{40})\s*$')
+
+class CherryPick(Command):
+ common = True
+ helpSummary = "Cherry-pick a change."
+ helpUsage = """
+%prog <sha1>
+"""
+ helpDescription = """
+'%prog' cherry-picks a change from one branch to another.
+The change id will be updated, and a reference to the old
+change id will be added.
+"""
+
+ def _Options(self, p):
+ pass
+
+ def Execute(self, opt, args):
+ if len(args) != 1:
+ self.Usage()
+
+ reference = args[0]
+
+ p = GitCommand(None,
+ ['rev-parse', '--verify', reference],
+ capture_stdout = True,
+ capture_stderr = True)
+ if p.Wait() != 0:
+ print >>sys.stderr, p.stderr
+ sys.exit(1)
+ sha1 = p.stdout.strip()
+
+ p = GitCommand(None, ['cat-file', 'commit', sha1], capture_stdout=True)
+ if p.Wait() != 0:
+ print >>sys.stderr, "error: Failed to retrieve old commit message"
+ sys.exit(1)
+ old_msg = self._StripHeader(p.stdout)
+
+ p = GitCommand(None,
+ ['cherry-pick', sha1],
+ capture_stdout = True,
+ capture_stderr = True)
+ status = p.Wait()
+
+ print >>sys.stdout, p.stdout
+ print >>sys.stderr, p.stderr
+
+ if status == 0:
+ # The cherry-pick was applied correctly. We just need to edit the
+ # commit message.
+ new_msg = self._Reformat(old_msg, sha1)
+
+ p = GitCommand(None, ['commit', '--amend', '-F', '-'],
+ provide_stdin = True,
+ capture_stdout = True,
+ capture_stderr = True)
+ p.stdin.write(new_msg)
+ if p.Wait() != 0:
+ print >>sys.stderr, "error: Failed to update commit message"
+ sys.exit(1)
+
+ else:
+ print >>sys.stderr, """\
+NOTE: When committing (please see above) and editing the commit message,
+please remove the old Change-Id-line and add:
+"""
+ print >>sys.stderr, self._GetReference(sha1)
+ print >>sys.stderr
+
+ def _IsChangeId(self, line):
+ return CHANGE_ID_RE.match(line)
+
+ def _GetReference(self, sha1):
+ return "(cherry picked from commit %s)" % sha1
+
+ def _StripHeader(self, commit_msg):
+ lines = commit_msg.splitlines()
+ return "\n".join(lines[lines.index("")+1:])
+
+ def _Reformat(self, old_msg, sha1):
+ new_msg = []
+
+ for line in old_msg.splitlines():
+ if not self._IsChangeId(line):
+ new_msg.append(line)
+
+ # Add a blank line between the message and the change id/reference
+ try:
+ if new_msg[-1].strip() != "":
+ new_msg.append("")
+ except IndexError:
+ pass
+
+ new_msg.append(self._GetReference(sha1))
+ return "\n".join(new_msg)
