add --no-ff to git pull in test_pr

fast-forward could result in the subsequent `git commit` call failing with nothing to commit.

tools/test_pr.py

@@ -1,244 +1,244 b''
 #!/usr/bin/env python
 """
 This is a script for testing pull requests for IPython. It merges the pull
 request with current master, installs and tests on all available versions of
 Python, and posts the results to Gist if any tests fail.
 
 Usage:
     python test_pr.py 1657
 """
 from __future__ import print_function
 
 import errno
 from glob import glob
 import io
 import json
 import os
 import pickle
 import re
 import requests
 import shutil
 import time
 from subprocess import call, check_call, check_output, PIPE, STDOUT, CalledProcessError
 import sys
 
 import gh_api
 
 basedir = os.path.join(os.path.expanduser("~"), ".ipy_pr_tests")
 repodir = os.path.join(basedir, "ipython")
 ipy_repository = 'git://github.com/ipython/ipython.git'
 gh_project="ipython/ipython"
 
 supported_pythons = ['python2.6', 'python2.7', 'python3.1', 'python3.2']
 unavailable_pythons = []
 
 def available_python_versions():
     """Get the executable names of available versions of Python on the system.
     """
     del unavailable_pythons[:]
     for py in supported_pythons:
         try:
             check_call([py, '-c', 'import nose'], stdout=PIPE)
             yield py
         except (OSError, CalledProcessError):
             unavailable_pythons.append(py)
 
 venvs = []
 
 def setup():
     """Prepare the repository and virtualenvs."""
     global venvs
     
     try:
         os.mkdir(basedir)
     except OSError as e:
         if e.errno != errno.EEXIST:
             raise
     os.chdir(basedir)
     
     # Delete virtualenvs and recreate
     for venv in glob('venv-*'):
         shutil.rmtree(venv)
     for py in available_python_versions():
         check_call(['virtualenv', '-p', py, '--system-site-packages', 'venv-%s' % py])
         venvs.append((py, 'venv-%s' % py))
     
     # Check out and update the repository
     if not os.path.exists('ipython'):
         check_call(['git', 'clone', ipy_repository])
     os.chdir(repodir)
     check_call(['git', 'checkout', 'master'])
     check_call(['git', 'pull', ipy_repository, 'master'])
     os.chdir(basedir)
 
 missing_libs_re = re.compile(r"Tools and libraries NOT available at test time:\n"
                              r"\s*(.*?)\n")
 def get_missing_libraries(log):
     m = missing_libs_re.search(log)
     if m:
         return m.group(1)
 
 def get_branch(repo, branch, owner, mergeable):
     os.chdir(repodir)
     if mergeable:
         merged_branch = "%s-%s" % (owner, branch)
         # Delete the branch first
         call(['git', 'branch', '-D', merged_branch])
         check_call(['git', 'checkout', '-b', merged_branch])
-        check_call(['git', 'pull', '--no-commit', repo, branch])
+        check_call(['git', 'pull', '--no-ff', '--no-commit', repo, branch])
         check_call(['git', 'commit', '-m', "merge %s/%s" % (repo, branch)])
     else:
         # Fetch the branch without merging it.
         check_call(['git', 'fetch', repo, branch])
         check_call(['git', 'checkout', 'FETCH_HEAD'])
     os.chdir(basedir)
 
 def run_tests(venv):
     py = os.path.join(basedir, venv, 'bin', 'python')
     print(py)
     os.chdir(repodir)
     # cleanup build-dir
     if os.path.exists('build'):
         shutil.rmtree('build')
     check_call([py, 'setup.py', 'install'])
     os.chdir(basedir)
     
     iptest = os.path.join(basedir, venv, 'bin', 'iptest')
     if not os.path.exists(iptest):
         iptest = os.path.join(basedir, venv, 'bin', 'iptest3')
         
     print("\nRunning tests, this typically takes a few minutes...")
     try:
         return True, check_output([iptest], stderr=STDOUT).decode('utf-8')
     except CalledProcessError as e:
         return False, e.output.decode('utf-8')
 
 def markdown_format(pr, results_urls):
     def format_result(py, passed, gist_url, missing_libraries):
         s = "* %s: " % py
         if passed:
             s += "OK"
         else:
             s += "Failed, log at %s" % gist_url
         if missing_libraries:
             s += " (libraries not available: " + missing_libraries + ")"
         return s
     
     if pr['mergeable']:
         com = pr['head']['sha'][:7] + " merged into master"
     else:
         com = pr['head']['sha'][:7] + " (can't merge cleanly)"
     lines = ["**Test results for commit %s**" % com,
              "Platform: " + sys.platform,
              ""] + \
             [format_result(*r) for r in results_urls] + \
             ["",
              "Not available for testing: " + ", ".join(unavailable_pythons)] 
     return "\n".join(lines)
 
 def post_results_comment(pr, results, num):
     body = markdown_format(pr, results)
     gh_api.post_issue_comment(gh_project, num, body)
 
 def print_results(pr, results_urls):
     print("\n")
     if pr['mergeable']:
         print("**Test results for commit %s merged into master**" % pr['head']['sha'][:7])
     else:
         print("**Test results for commit %s (can't merge cleanly)**" % pr['head']['sha'][:7])
     print("Platform:", sys.platform)
     for py, passed, gist_url, missing_libraries in results_urls:
         if passed:
             print(py, ":", "OK")
         else:
             print(py, ":", "Failed")
             print("    Test log:", gist_url)
         if missing_libraries:
             print("    Libraries not available:", missing_libraries)
     print("Not available for testing:", ", ".join(unavailable_pythons))
 
 def dump_results(num, results, pr):
     with open(os.path.join(basedir, 'lastresults.pkl'), 'wb') as f:
         pickle.dump((num, results, pr), f)
 
 def load_results():
     with open(os.path.join(basedir, 'lastresults.pkl'), 'rb') as f:
         return pickle.load(f)
 
 def save_logs(results, pr):
     results_paths = []
     for py, passed, log, missing_libraries in results:
         if passed:
             results_paths.append((py, passed, None, missing_libraries))
         else:
             
             result_locn = os.path.abspath(os.path.join('venv-%s' % py,
                                         pr['head']['sha'][:7]+".log"))
             with io.open(result_locn, 'w', encoding='utf-8') as f:
                 f.write(log)
         
             results_paths.append((py, False, result_locn, missing_libraries))
     
     return results_paths
 
 def post_logs(results):
     results_urls = []
     for py, passed, log, missing_libraries in results:
         if passed:
             results_urls.append((py, passed, None, missing_libraries))
         else:
             result_locn = gh_api.post_gist(log, description='IPython test log',
                                             filename="results.log", auth=True)
             results_urls.append((py, False, result_locn, missing_libraries))
     
     return results_urls
 
 def test_pr(num, post_results=True):
     # Get Github authorisation first, so that the user is prompted straight away
     # if their login is needed.
     if post_results:
         gh_api.get_auth_token()
     
     setup()
     pr = gh_api.get_pull_request(gh_project, num)
     get_branch(repo=pr['head']['repo']['clone_url'], 
                  branch=pr['head']['ref'],
                  owner=pr['head']['repo']['owner']['login'],
                  mergeable=pr['mergeable'],
               )
     
     results = []
     for py, venv in venvs:
         tic = time.time()
         passed, log = run_tests(venv)
         elapsed = int(time.time() - tic)
         print("Ran tests with %s in %is" % (py, elapsed))
         missing_libraries = get_missing_libraries(log)
         if passed:
             results.append((py, True, None, missing_libraries))
         else:
             results.append((py, False, log, missing_libraries))
     
     dump_results(num, results, pr)
     
     results_paths = save_logs(results, pr)
     print_results(pr, results_paths)
     
     if post_results:
         results_urls = post_logs(results)
         post_results_comment(pr, results_urls, num)
         print("(Posted to Github)")
     else:
         post_script = os.path.join(os.path.dirname(sys.argv[0]), "post_pr_test.py")
         print("To post the results to Github, run", post_script)
     
 
 if __name__ == '__main__':
     import argparse
     parser = argparse.ArgumentParser(description="Test an IPython pull request")
     parser.add_argument('-p', '--publish', action='store_true',
                         help="Publish the results to Github")
     parser.add_argument('number', type=int, help="The pull request number")
     
     args = parser.parse_args()
     test_pr(args.number, post_results=args.publish)