get files list in backport_pr

fixes omission of new files in backport commits

tools/backport_pr.py

@@ -19,7 +19,7 b' import sys'
 from subprocess import Popen, PIPE, check_call, check_output
 from urllib import urlopen
 
-from gh_api import get_pull_request
+from gh_api import get_pull_request, get_pull_request_files
 
 def find_rejects(root='.'):
     for dirname, dirs, files in os.walk(root):
@@ -37,7 +37,8 b" def backport_pr(branch, num, project='ipython/ipython'):"
     current_branch = get_current_branch()
     if branch != current_branch:
         check_call(['git', 'checkout', branch])
-    pr = get_pull_request(project, num)
+    pr = get_pull_request(project, num, auth=True)
+    files = get_pull_request_files(project, num, auth=True)
     patch_url = pr['patch_url']
     title = pr['title']
     description = pr['body']
@@ -65,9 +66,16 b" def backport_pr(branch, num, project='ipython/ipython'):"
     
     p = Popen(['git', 'apply'], stdin=PIPE)
     a,b = p.communicate(patch)
+    
+    filenames = [ f['filename'] for f in files ]
+    add = Popen(['git', 'add'] + filenames)
+    add.wait()
+    if add.returncode:
+        print("git add %s failed!" % filenames)
+        return 1
 
-    commit = Popen(['git', 'commit', '-a', '-m', msg])
-    commit.communicate()
+    commit = Popen(['git', 'commit', '-m', msg])
+    commit.wait()
     if commit.returncode:
         print("commit failed!")
         return 1

tools/gh_api.py

@@ -107,6 +107,15 b' def get_pull_request(project, num, auth=False):'
     response.raise_for_status()
     return json.loads(response.text, object_hook=Obj)
 
+def get_pull_request_files(project, num, auth=False):
+    """get list of files in a pull request"""
+    url = "https://api.github.com/repos/{project}/pulls/{num}/files".format(project=project, num=num)
+    if auth:
+        header = make_auth_header()
+    else:
+        header = None
+    return get_paged_request(url, headers=header)
+
 element_pat = re.compile(r'<(.+?)>')
 rel_pat = re.compile(r'rel=[\'"](\w+)[\'"]')