Auto merge of #56951 - oli-obk:auto_toolstate_issue, r=kennytm

Automatically open an issue when a tool breaks

cc @nikomatsakis

fixes https://github.com/rust-lang-nursery/rust-toolstate/issues/6

documentation about issue opening via the github api: https://developer.github.com/v3/issues/#create-an-issue

src/tools/publish_toolstate.py

@@ -24,6 +24,17 @@ MAINTAINERS = {
     'rust-by-example': '@steveklabnik @marioidival @projektir',
 }
 
+REPOS = {
+    'miri': 'https://github.com/solson/miri',
+    'clippy-driver': 'https://github.com/rust-lang/rust-clippy',
+    'rls': 'https://github.com/rust-lang/rls',
+    'rustfmt': 'https://github.com/rust-lang/rustfmt',
+    'book': 'https://github.com/rust-lang/book',
+    'nomicon': 'https://github.com/rust-lang-nursery/nomicon',
+    'reference': 'https://github.com/rust-lang-nursery/reference',
+    'rust-by-example': 'https://github.com/rust-lang/rust-by-example',
+}
+
 
 def read_current_status(current_commit, path):
     '''Reads build status of `current_commit` from content of `history/*.tsv`
@@ -35,11 +46,48 @@ def read_current_status(current_commit, path):
                 return json.loads(status)
     return {}
 
+def issue(
+    tool,
+    maintainers,
+    relevant_pr_number,
+    relevant_pr_user,
+    pr_reviewer,
+):
+    # Open an issue about the toolstate failure.
+    gh_url = 'https://api.github.com/repos/rust-lang/rust/issues'
+    assignees = [x.strip() for x in maintainers.split('@') if x != '']
+    assignees.append(relevant_pr_user)
+    response = urllib2.urlopen(urllib2.Request(
+        gh_url,
+        json.dumps({
+            'body': textwrap.dedent('''\
+            Hello, this is your friendly neighborhood mergebot.
+            After merging PR {}, I observed that the tool {} no longer builds.
+            A follow-up PR to the repository {} is needed to fix the fallout.
+
+            cc @{}, do you think you would have time to do the follow-up work?
+            If so, that would be great!
+
+            cc @{}, the PR reviewer, and @rust-lang/compiler -- nominating for prioritization.
+
+            ''').format(relevant_pr_number, tool, REPOS[tool], relevant_pr_user, pr_reviewer),
+            'title': '`{}` no longer builds after {}'.format(tool, relevant_pr_number),
+            'assignees': assignees,
+            'labels': ['T-compiler', 'I-nominated'],
+        }),
+        {
+            'Authorization': 'token ' + github_token,
+            'Content-Type': 'application/json',
+        }
+    ))
+    response.read()
 
 def update_latest(
     current_commit,
     relevant_pr_number,
     relevant_pr_url,
+    relevant_pr_user,
+    pr_reviewer,
     current_datetime
 ):
     '''Updates `_data/latest.json` to match build result of the given commit.
@@ -64,19 +112,41 @@ def update_latest(
         for status in latest:
             tool = status['tool']
             changed = False
+            build_failed = False
 
             for os, s in current_status.items():
                 old = status[os]
                 new = s.get(tool, old)
                 status[os] = new
                 if new > old:
+                    # things got fixed or at least the status quo improved
                     changed = True
                     message += '🎉 {} on {}: {} → {} (cc {}, @rust-lang/infra).\n' \
                         .format(tool, os, old, new, MAINTAINERS.get(tool))
                 elif new < old:
+                    # tests or builds are failing and were not failing before
                     changed = True
-                    message += '💔 {} on {}: {} → {} (cc {}, @rust-lang/infra).\n' \
-                        .format(tool, os, old, new, MAINTAINERS.get(tool))
+                    title = '💔 {} on {}: {} → {}' \
+                        .format(tool, os, old, new)
+                    message += '{} (cc {}, @rust-lang/infra).\n' \
+                        .format(title, MAINTAINERS.get(tool))
+                    # only create issues for build failures. Other failures can be spurious
+                    if new == 'build-fail':
+                        build_failed = True
+
+            if build_failed:
+                try:
+                    issue(
+                        tool, MAINTAINERS.get(tool),
+                        relevant_pr_number, relevant_pr_user, pr_reviewer,
+                    )
+                except IOError as (errno, strerror):
+                    # network errors will simply end up not creating an issue, but that's better
+                    # than failing the entire build job
+                    print "I/O error({0}): {1}".format(errno, strerror)
+                except:
+                    print "Unexpected error:", sys.exc_info()[0]
+                    raise
 
             if changed:
                 status['commit'] = current_commit
@@ -99,20 +169,30 @@ if __name__ == '__main__':
     save_message_to_path = sys.argv[3]
     github_token = sys.argv[4]
 
-    relevant_pr_match = re.search('#([0-9]+)', cur_commit_msg)
+    # assume that PR authors are also owners of the repo where the branch lives
+    relevant_pr_match = re.search(
+        'Auto merge of #([0-9]+) - ([^:]+):[^,]+ r=([^\s]+)',
+        cur_commit_msg,
+    )
     if relevant_pr_match:
         number = relevant_pr_match.group(1)
+        relevant_pr_user = relevant_pr_match.group(2)
         relevant_pr_number = 'rust-lang/rust#' + number
         relevant_pr_url = 'https://github.com/rust-lang/rust/pull/' + number
+        pr_reviewer = relevant_pr_match.group(3)
     else:
         number = '-1'
+        relevant_pr_user = '<unknown user>'
         relevant_pr_number = '<unknown PR>'
         relevant_pr_url = '<unknown>'
+        pr_reviewer = '<unknown reviewer>'
 
     message = update_latest(
         cur_commit,
         relevant_pr_number,
         relevant_pr_url,
+        relevant_pr_user,
+        pr_reviewer,
         cur_datetime
     )
     if not message: