merge_spark_pr.py

#!/usr/bin/python

#
# Licensed to the Apache Software Foundation (ASF) under one or more
# contributor license agreements.  See the NOTICE file distributed with
# this work for additional information regarding copyright ownership.
# The ASF licenses this file to You 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.
#

# Utility for creating well-formed pull request merges and pushing them to Apache.
#   usage: ./apache-pr-merge.py    (see config env vars below)
#
# This utility assumes you already have local a Spark git folder and that you
# have added remotes corresponding to both (i) the github apache Spark 
# mirror and (ii) the apache git repo.

import json
import os
import re
import subprocess
import sys
import tempfile
import urllib2

try:
  import jira.client
  JIRA_IMPORTED=True
except ImportError:
  JIRA_IMPORTED=False

# Location of your Spark git development area
SPARK_HOME = os.environ.get("SPARK_HOME", "/home/patrick/Documents/spark")
# Remote name which points to the Gihub site
PR_REMOTE_NAME = os.environ.get("PR_REMOTE_NAME", "apache-github")
# Remote name which points to Apache git
PUSH_REMOTE_NAME = os.environ.get("PUSH_REMOTE_NAME", "apache")
# ASF JIRA username
JIRA_USERNAME = os.environ.get("JIRA_USERNAME", "pwendell")
# ASF JIRA password
JIRA_PASSWORD = os.environ.get("JIRA_PASSWORD", "1234")

GITHUB_BASE = "https://github.com/apache/spark/pull"
GITHUB_API_BASE = "https://api.github.com/repos/apache/spark"
JIRA_BASE = "https://issues.apache.org/jira/browse"
JIRA_API_BASE = "https://issues.apache.org/jira"
# Prefix added to temporary branches
BRANCH_PREFIX = "PR_TOOL"

os.chdir(SPARK_HOME)

def get_json(url):
  try:
    return json.load(urllib2.urlopen(url))
  except urllib2.HTTPError as e:
    print "Unable to fetch URL, exiting: %s" % url
    sys.exit(-1)

def fail(msg):
  print msg
  clean_up()
  sys.exit(-1)

def run_cmd(cmd):
  if isinstance(cmd, list):
    return subprocess.check_output(cmd)
  else:
    return subprocess.check_output(cmd.split(" "))

def continue_maybe(prompt):
  result = raw_input("\n%s (y/n): " % prompt)
  if result.lower() != "y":
    fail("Okay, exiting")

original_head = run_cmd("git rev-parse HEAD")[:8]

def clean_up():
  print "Restoring head pointer to %s" % original_head
  run_cmd("git checkout %s" % original_head)

  branches = run_cmd("git branch").replace(" ", "").split("\n")

  for branch in filter(lambda x: x.startswith(BRANCH_PREFIX), branches):
    print "Deleting local branch %s" % branch
    run_cmd("git branch -D %s" % branch)

# merge the requested PR and return the merge hash
def merge_pr(pr_num, target_ref):
  pr_branch_name = "%s_MERGE_PR_%s" % (BRANCH_PREFIX, pr_num)
  target_branch_name = "%s_MERGE_PR_%s_%s" % (BRANCH_PREFIX, pr_num, target_ref.upper())
  run_cmd("git fetch %s pull/%s/head:%s" % (PR_REMOTE_NAME, pr_num, pr_branch_name))
  run_cmd("git fetch %s %s:%s" % (PUSH_REMOTE_NAME, target_ref, target_branch_name))
  run_cmd("git checkout %s" % target_branch_name)
  
  had_conflicts = False
  try:
    run_cmd(['git', 'merge', pr_branch_name, '--squash'])
  except Exception as e:
    msg = "Error merging: %s\nWould you like to manually fix-up this merge?" % e
    continue_maybe(msg)
    msg = "Okay, please fix any conflicts and 'git add' conflicting files... Finished?"
    continue_maybe(msg)
    had_conflicts = True

  commit_authors = run_cmd(['git', 'log', 'HEAD..%s' % pr_branch_name, 
    '--pretty=format:%an <%ae>']).split("\n")
  distinct_authors = sorted(set(commit_authors), key=lambda x: commit_authors.count(x), 
    reverse=True)
  primary_author = distinct_authors[0]
  commits = run_cmd(['git', 'log', 'HEAD..%s' % pr_branch_name, 
    '--pretty=format:%h [%an] %s']).split("\n\n")

  merge_message_flags = []

  for p in [title, body]:
    merge_message_flags += ["-m", p]

  authors = "\n".join(["Author: %s" % a for a in distinct_authors])

  merge_message_flags += ["-m", authors]

  if had_conflicts:
    committer_name = run_cmd("git config --get user.name").strip()
    committer_email = run_cmd("git config --get user.email").strip()
    message = "This patch had conflicts when merged, resolved by\nCommitter: %s <%s>" % (
      committer_name, committer_email)
    merge_message_flags += ["-m", message]

  # The string "Closes #%s" string is required for GitHub to correctly close the PR
  merge_message_flags += ["-m",
    "Closes #%s from %s and squashes the following commits:" % (pr_num, pr_repo_desc)]
  for c in commits:
    merge_message_flags += ["-m", c]

  run_cmd(['git', 'commit', '--author="%s"' % primary_author] + merge_message_flags)

  continue_maybe("Merge complete (local ref %s). Push to %s?" % (
    target_branch_name, PUSH_REMOTE_NAME))

  try:
    run_cmd('git push %s %s:%s' % (PUSH_REMOTE_NAME, target_branch_name, target_ref))
  except Exception as e:
    clean_up()
    fail("Exception while pushing: %s" % e)
  
  merge_hash = run_cmd("git rev-parse %s" % target_branch_name)[:8]
  clean_up()
  print("Pull request #%s merged!" % pr_num)
  print("Merge hash: %s" % merge_hash)
  return merge_hash


def cherry_pick(pr_num, merge_hash, default_branch):
  pick_ref = raw_input("Enter a branch name [%s]: " % default_branch)
  if pick_ref == "":
    pick_ref = default_branch

  pick_branch_name = "%s_PICK_PR_%s_%s" % (BRANCH_PREFIX, pr_num, pick_ref.upper())

  run_cmd("git fetch %s %s:%s" % (PUSH_REMOTE_NAME, pick_ref, pick_branch_name))
  run_cmd("git checkout %s" % pick_branch_name)
  run_cmd("git cherry-pick -sx %s" % merge_hash)
  
  continue_maybe("Pick complete (local ref %s). Push to %s?" % (
    pick_branch_name, PUSH_REMOTE_NAME))

  try:
    run_cmd('git push %s %s:%s' % (PUSH_REMOTE_NAME, pick_branch_name, pick_ref))
  except Exception as e:
    clean_up()
    fail("Exception while pushing: %s" % e)

  pick_hash = run_cmd("git rev-parse %s" % pick_branch_name)[:8]
  clean_up()

  print("Pull request #%s picked into %s!" % (pr_num, pick_ref))
  print("Pick hash: %s" % pick_hash)
  return pick_ref

def fix_version_from_branch(branch, versions):
  # Note: Assumes this is a sorted (newest->oldest) list of un-released versions
  if branch == "master":
    return versions[0]
  else:
    branch_ver = branch.replace("branch-", "")
    return filter(lambda x: x.name.startswith(branch_ver), versions)[-1]

def resolve_jira(title, merge_branches, comment):
  asf_jira = jira.client.JIRA({'server': JIRA_API_BASE},
    basic_auth=(JIRA_USERNAME, JIRA_PASSWORD))

  default_jira_id = ""
  search = re.findall("SPARK-[0-9]{4,5}", title)
  if len(search) > 0:
    default_jira_id = search[0]

  jira_id = raw_input("Enter a JIRA id [%s]: " % default_jira_id)
  if jira_id == "":
    jira_id = default_jira_id

  try:
    issue = asf_jira.issue(jira_id)
  except Exception as e:
    fail("ASF JIRA could not find %s\n%s" % (jira_id, e))

  cur_status = issue.fields.status.name
  cur_summary = issue.fields.summary
  cur_assignee = issue.fields.assignee
  if cur_assignee == None:
    cur_assignee = "NOT ASSIGNED!!!"
  else:
    cur_assignee = cur_assignee.displayName

  if cur_status == "Resolved" or cur_status == "Closed":
    fail("JIRA issue %s already has status '%s'" % (jira_id, cur_status))
  print ("=== JIRA %s ===" % jira_id)
  print ("summary\t\t%s\nassignee\t%s\nstatus\t\t%s\nurl\t\t%s/%s\n" % (
    cur_summary, cur_assignee, cur_status, JIRA_BASE, jira_id))

  versions = asf_jira.project_versions("SPARK")
  versions = sorted(versions, key = lambda x: x.name, reverse=True)
  versions = filter(lambda x: x.raw['released'] == False, versions)

  default_fix_versions = map(lambda x: fix_version_from_branch(x, versions).name, merge_branches)
  for v in default_fix_versions:
    # Handles the case where we have forked a release branch but not yet made the release.
    # In this case, if the PR is committed to the master branch and the release branch, we
    # only consider the release branch to be the fix version. E.g. it is not valid to have
    # both 1.1.0 and 1.0.0 as fix versions.
    (major, minor, patch) = v.split(".")
    if patch == "0":
      previous = "%s.%s.%s" % (major, int(minor) - 1, 0)
      if previous in default_fix_versions:
        default_fix_versions = filter(lambda x: x != v, default_fix_versions)
  default_fix_versions = ",".join(default_fix_versions)

  fix_versions = raw_input("Enter comma-separated fix version(s) [%s]: " % default_fix_versions)
  if fix_versions == "":
    fix_versions = default_fix_versions
  fix_versions = fix_versions.replace(" ", "").split(",")

  def get_version_json(version_str):
    return filter(lambda v: v.name == version_str, versions)[0].raw
  jira_fix_versions = map(lambda v: get_version_json(v), fix_versions)

  resolve = filter(lambda a: a['name'] == "Resolve Issue", asf_jira.transitions(jira_id))[0]
  asf_jira.transition_issue(jira_id, resolve["id"], fixVersions=jira_fix_versions, comment=comment)

  print "Succesfully resolved %s with fixVersions=%s!" % (jira_id, fix_versions)

branches = get_json("%s/branches" % GITHUB_API_BASE)
branch_names = filter(lambda x: x.startswith("branch-"), [x['name'] for x in branches])
# Assumes branch names can be sorted lexicographically
latest_branch = sorted(branch_names, reverse=True)[0]

pr_num = raw_input("Which pull request would you like to merge? (e.g. 34): ")
pr = get_json("%s/pulls/%s" % (GITHUB_API_BASE, pr_num))

url = pr["url"]
title = pr["title"]
body = pr["body"]
target_ref = pr["base"]["ref"]
user_login = pr["user"]["login"]
base_ref = pr["head"]["ref"]
pr_repo_desc = "%s/%s" % (user_login, base_ref)

if pr["merged"] == True:
  print "Pull request %s has already been merged, assuming you want to backport" % pr_num
  merge_commit_desc = run_cmd(['git', 'log', '--merges', '--first-parent', 
    '--grep=pull request #%s' % pr_num, '--oneline']).split("\n")[0]
  if merge_commit_desc == "":
    fail("Couldn't find any merge commit for #%s, you may need to update HEAD." % pr_num)

  merge_hash = merge_commit_desc[:7]  
  message = merge_commit_desc[8:]
  
  print "Found: %s" % message
  maybe_cherry_pick(pr_num, merge_hash, latest_branch)
  sys.exit(0)

if not bool(pr["mergeable"]):
  msg = "Pull request %s is not mergeable in its current form.\n" % pr_num + \
    "Continue? (experts only!)"
  continue_maybe(msg)

print ("\n=== Pull Request #%s ===" % pr_num)
print ("title\t%s\nsource\t%s\ntarget\t%s\nurl\t%s" % (
  title, pr_repo_desc, target_ref, url))
continue_maybe("Proceed with merging pull request #%s?" % pr_num)

merged_refs = [target_ref]

merge_hash = merge_pr(pr_num, target_ref)

pick_prompt = "Would you like to pick %s into another branch?" % merge_hash
while raw_input("\n%s (y/n): " % pick_prompt).lower() == "y":
  merged_refs = merged_refs + [cherry_pick(pr_num, merge_hash, latest_branch)]

if JIRA_IMPORTED:
  continue_maybe("Would you like to update an associated JIRA?")
  jira_comment = "Issue resolved by pull request %s\n[%s/%s]" % (pr_num, GITHUB_BASE, pr_num)
  resolve_jira(title, merged_refs, jira_comment)
else:
  print "Could not find jira-python library. Run 'sudo pip install jira-python' to install."
  print "Exiting without trying to close the associated JIRA."