Merge pull request #1759 from Carreau/mpr

Add git-mpr, to merge PR(s) from github just by number(s).

Inspired by git-mrb and test_pr, I thougth it would be usefull to be able to merge PR only by giving their number. Hence `git merge-pull-request`or `git-mpr`.

usage: 
```bash
$ git mpr -h                                                                          ~/ipython/tools
usage: git-mpr [-h] [-l | -a | -m [pr-number [pr-number ...]]]

Merge (one|many) github pull request by their number. If pull request can't be
merge as is, cancel merge, and continue to the next if any.

optional arguments:
  -h, --help            show this help message and exit
  -l, --list            list PR, their number and their mergeability
  -a, --merge-all       try to merge as many PR as possible, one by one
  -m [pr-number [pr-number ...]], --merge [pr-number [pr-number ...]]
                        The pull request numbers
```

examples :
```bash
$ git mpr --list  
*  #1758 [√]:  test_pr, fallback on http if git protocol fail, and SSL errors...
*  #1755 [√]:  test for pygments before running qt tests
*  #1715 [√]:  Fix for  #1688, traceback-unicode issue
[...]
*  #1493 [√]:  Selenium web tests proof-of-concept
*  #1471 [ ]:  simplify IPython.parallel connections and enable Controller Resume
*  #1343 [ ]:  Add prototype shutdown button to Notebook dashboard
*  #1285 [√]:  Implementation of grepping the input history using several patterns
*  #1215 [√]:  updated %quickref to show short-hand for %sc and %sx
```
PR number, mergeability and title
Quite slow, as it does 1 api call by PR, since api does not give mergeability anymore if you ask for the list of all PRs at once.

merge one or more PR (skip the ones with conflict and present a nice list to copy and past to do it by hand) 

```bash
$ git mpr --merge [pr-number [pr-number ...]]]
[...]
*************************************************************************************
the following branch have not been merged automatically, considere doing it by hand :
PR 1630: git pull https://github.com/minrk/ipython.git mergekernel
PR 1343: git pull https://github.com/takluyver/ipython.git notebook-shutdown
PR 1715: git pull https://github.com/jstenar/ipython.git ultratb-pycolorize-unicode
PR 1732: git pull https://github.com/fperez/ipython.git cellmagics
PR 1471: git pull https://github.com/minrk/ipython.git connection
PR 1674: git pull https://github.com/mdboom/ipython.git notebook-carriage-return
*************************************************************************************
```

And last, 
```
git mpr --merge-all
```

That is pretty self explainatory

tools/git-mpr.py

@@ -0,0 +1,127 b''
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+"""
+Usage:
+    python git-mpr.py -m 1657
+"""
+from __future__ import print_function
+
+import argparse
+from subprocess import check_call, CalledProcessError
+
+import gh_api
+
+ipy_repository = 'git://github.com/ipython/ipython.git'
+gh_project = "ipython/ipython"
+not_merged = {}
+
+def merge_branch(repo, branch ):
+    """try to merge the givent branch into the current one
+    
+    If something does not goes smoothly, merge is aborted
+    
+    Returns True if merge sucessfull, False otherwise
+    """
+    # Delete the branch first
+    try :
+        check_call(['git', 'pull', '--no-edit', repo, branch])
+    except CalledProcessError :
+        check_call(['git', 'merge', '--abort'])
+        return False
+    return True
+
+
+def merge_pr(num, github_api=3):
+    """ try to merge the branch of PR `num` into current branch
+    
+    github_api : use github api v2 (to bypass https and issues with proxy) to find the
+             remote branch that should be merged by it's number
+    """
+    # Get Github authorisation first, so that the user is prompted straight away
+    # if their login is needed.
+    
+    pr = gh_api.get_pull_request(gh_project, num, github_api)
+    if github_api == 2:
+        repo = pr['head']['repository']['url']
+    elif github_api == 3 :
+        repo = pr['head']['repo']['clone_url']
+
+
+    branch = pr['head']['ref']
+    mergeable = merge_branch(repo=repo, 
+                 branch=branch,
+              )
+    if not mergeable :
+        cmd = "git pull "+repo+" "+branch
+        not_merged[str(num)] = cmd
+        print("==============================================================================")
+        print("Something went wrong merging this branch, you can try it manually by runngin :")
+        print(cmd)
+        print("==============================================================================")
+        
+    
+def main(*args):
+    parser = argparse.ArgumentParser(
+            description="""
+                Merge (one|many) github pull request by their number.\
+                
+                If pull request can't be merge as is, cancel merge,
+                and continue to the next if any.
+                """
+            )
+    parser.add_argument('-v2', '--githubapiv2', action='store_const', const=2)
+
+    grp = parser.add_mutually_exclusive_group()
+    grp.add_argument(
+            '-l',
+            '--list',
+            action='store_const',
+            const=True,
+            help='list PR, their number and their mergeability')
+    grp.add_argument('-a',
+            '--merge-all',
+            action='store_const',
+            const=True ,
+            help='try to merge as many PR as possible, one by one')
+    grp.add_argument('-m',
+            '--merge',
+            type=int,
+            help="The pull request numbers",
+            nargs='*',
+            metavar='pr-number')
+    args = parser.parse_args()
+    if args.githubapiv2 == 2 :
+        github_api = 2
+    else  :
+        github_api = 3
+
+    if(args.list):
+        pr_list = gh_api.get_pulls_list(gh_project, github_api)
+        for pr in pr_list :
+            mergeable = gh_api.get_pull_request(gh_project, pr['number'], github_api=github_api)['mergeable']
+
+            ismgb = u"√" if mergeable else " "
+            print(u"* #{number} [{ismgb}]:  {title}".format(
+                number=pr['number'],
+                title=pr['title'],
+                ismgb=ismgb))
+
+    if(args.merge_all):
+        pr_list = gh_api.get_pulls_list(gh_project)
+        for pr in pr_list :
+            merge_pr(pr['number'])
+
+
+    elif args.merge:
+        for num in args.merge :
+            merge_pr(num, github_api=github_api)
+
+    if not_merged :
+        print('*************************************************************************************')
+        print('the following branch have not been merged automatically, considere doing it by hand :')
+        for num, cmd in not_merged.items() :
+            print( "PR {num}: {cmd}".format(num=num, cmd=cmd))
+        print('*************************************************************************************')
+
+if __name__ == '__main__':
+    main()

tools/gh_api.py

@@ -1,80 +1,104 b''
 """Functions for Github authorisation."""
 from __future__ import print_function
 
 try:
     input = raw_input
 except NameError:
     pass
 
 import requests
 import getpass
 import json
 
 # Keyring stores passwords by a 'username', but we're not storing a username and
 # password
 fake_username = 'ipython_tools'
 
 token = None
 def get_auth_token():
     global token
     
     if token is not None:
         return token
     
     import keyring
     token = keyring.get_password('github', fake_username)
     if token is not None:
         return token
     
     print("Please enter your github username and password. These are not "
            "stored, only used to get an oAuth token. You can revoke this at "
            "any time on Github.")
     user = input("Username: ")
     pw = getpass.getpass("Password: ")
     
     auth_request = {
       "scopes": [
         "public_repo",
         "gist"
       ],
       "note": "IPython tools",
       "note_url": "https://github.com/ipython/ipython/tree/master/tools",
     }
     response = requests.post('https://api.github.com/authorizations',
                             auth=(user, pw), data=json.dumps(auth_request))
     response.raise_for_status()
     token = json.loads(response.text)['token']
     keyring.set_password('github', fake_username, token)
     return token
 
 def make_auth_header():
     return {'Authorization': 'token ' + get_auth_token()}
 
 def post_issue_comment(project, num, body):
     url = 'https://api.github.com/repos/{project}/issues/{num}/comments'.format(project=project, num=num)
     payload = json.dumps({'body': body})
     r = requests.post(url, data=payload, headers=make_auth_header())
 
 def post_gist(content, description='', filename='file', auth=False):
     """Post some text to a Gist, and return the URL."""
     post_data = json.dumps({
       "description": description,
       "public": True,
       "files": {
         filename: {
           "content": content
         }
       }
     }).encode('utf-8')
     
     headers = make_auth_header() if auth else {}
     response = requests.post("https://api.github.com/gists", data=post_data, headers=headers)
     response.raise_for_status()
     response_data = json.loads(response.text)
     return response_data['html_url']
     
-def get_pull_request(project, num):
-    url = "https://api.github.com/repos/{project}/pulls/{num}".format(project=project, num=num)
+def get_pull_request(project, num, github_api=3):
+    """get pull request info  by number
+
+    github_api : version of github api to use
+    """
+    if github_api==2 :
+        url = "http://github.com/api/v2/json/pulls/{project}/{num}".format(project=project, num=num)
+    elif github_api == 3:
+        url = "https://api.github.com/repos/{project}/pulls/{num}".format(project=project, num=num)
+    response = requests.get(url)
+    response.raise_for_status()
+    if github_api == 2 :
+        return json.loads(response.text)['pull']
+    return json.loads(response.text)
+
+def get_pulls_list(project, github_api=3):
+    """get pull request list
+
+    github_api : version of github api to use
+    """
+    if github_api == 3 :
+        url = "https://api.github.com/repos/{project}/pulls".format(project=project)
+    else :
+        url = "http://github.com/api/v2/json/pulls/{project}".format(project=project)
     response = requests.get(url)
     response.raise_for_status()
+    if github_api == 2 :
+        return json.loads(response.text)['pulls']
     return json.loads(response.text)