1 import os 2 import sys 3 import traceback 4 5 def main(argv): 6 # Only check the history if the build is running on a pull request. 7 # Build could be running on pull request using travis or kokoro. 8 if is_travis_pull_request() or is_kokoro_presubmit_request(): 9 # This function assumes that HEAD^1 is the base branch and HEAD^2 is the 10 # pull request. 11 exit_if_pull_request_has_merge_commits() 12 print 'Checked pull request history: SUCCEEDED' 13 else: 14 print 'Skipped history check.' 15 16 def is_kokoro_presubmit_request(): 17 '''Returns true if KOKORO_GITHUB_PULL_REQUEST_NUMBER is set.''' 18 if 'KOKORO_GITHUB_PULL_REQUEST_NUMBER' in os.environ: 19 return True 20 return False 21 22 def is_travis_pull_request(): 23 '''Returns true if TRAVIS_PULL_REQUEST is set to indicate a pull request.''' 24 if 'TRAVIS_PULL_REQUEST' in os.environ: 25 return os.environ['TRAVIS_PULL_REQUEST'] != 'false' 26 return False 27 28 def exit_if_pull_request_has_merge_commits(): 29 '''Exits with an error if any of the commits added by the pull request are 30 merge commits.''' 31 # Print the parents of each commit added by the pull request. 32 git_command = 'git log --format="%P" HEAD^1..HEAD^2' 33 for line in os.popen(git_command): 34 parents = line.split() 35 assert len(parents) >= 1, line 36 if len(parents) > 1: 37 print 'Pull request contains a merge commit:' 38 print_history() 39 print 'Checked pull request history: FAILED' 40 sys.exit(1) 41 42 def print_history(): 43 os.system('git log HEAD^1 HEAD^2 -30 --graph --oneline --decorate') 44 45 def read_process(command): 46 '''Runs a command and returns everything printed to stdout.''' 47 with os.popen(command, 'r') as fd: 48 return fd.read() 49 50 if __name__ == '__main__': 51 main(sys.argv) 52
