We are currently solving the following issue within our repository. Here is the issue text:
--- BEGIN ISSUE ---
mercurial project imported from bitbucket stuck in 'Triggered' state
The docs for pylibftdi are set to be built (via a POST trigger) from https://bitbucket.org/codedstructure/pylibftdi, but builds (https://readthedocs.org/builds/pylibftdi/) are stuck at 'Triggered'.

Based on comments in #435 I set the project up to build against a github mirror, and that worked successfully, so it seems (from #435) that this is likely an hg issue.


--- END ISSUE ---

Below are some code segments, each from a relevant file. One or more of these files may contain bugs.
--- BEGIN FILES ---
Path: `readthedocs/vcs_support/backends/hg.py`
Content:
```
1 import csv
2 from StringIO import StringIO
3 
4 from projects.exceptions import ProjectImportError
5 from vcs_support.base import BaseVCS, VCSVersion
6 
7 
8 class Backend(BaseVCS):
9     supports_tags = True
10     supports_branches = True
11     fallback_branch = 'default'
12 
13     def update(self):
14         super(Backend, self).update()
15         retcode = self.run('hg', 'status')[0]
16         if retcode == 0:
17             return self.pull()
18         else:
19             return self.clone()
20 
21     def pull(self):
22         pull_output = self.run('hg', 'pull')
23         if pull_output[0] != 0:
24             raise ProjectImportError(
25                 ("Failed to get code from '%s' (hg pull): %s"
26                  % (self.repo_url, pull_output[0]))
27             )
28         update_output = self.run('hg', 'update', '-C')[0]
29         if update_output[0] != 0:
30             raise ProjectImportError(
31                 ("Failed to get code from '%s' (hg update): %s"
32                  % (self.repo_url, pull_output[0]))
33             )
34         return update_output
35 
36     def clone(self):
37         output = self.run('hg', 'clone', self.repo_url, '.')
38         if output[0] != 0:
39             raise ProjectImportError(
40                 ("Failed to get code from '%s' (hg clone): %s"
41                  % (self.repo_url, output[0]))
42             )
43         return output
44 
45     @property
46     def branches(self):
47         retcode, stdout = self.run('hg', 'branches', '-q')[:2]
48         # error (or no tags found)
49         if retcode != 0:
50             return []
51         return self.parse_branches(stdout)
52 
53     def parse_branches(self, data):
54         """
55         stable
56         default
57         """
58 
59         names = [name.lstrip() for name in data.splitlines()]
60         return [VCSVersion(self, name, name) for name in names if name]
61 
62     @property
63     def tags(self):
64         retcode, stdout = self.run('hg', 'tags')[:2]
65         # error (or no tags found)
66         if retcode != 0:
67             return []
68         return self.parse_tags(stdout)
69 
70     def parse_tags(self, data):
71         """
72         Parses output of show-ref --tags, eg:
73 
74         tip                              278:c4b2d21db51a
75         0.2.2                            152:6b0364d98837
76         0.2.1                            117:a14b7b6ffa03
77         0.1                               50:30c2c6b3a055
78         """
79         # parse the lines into a list of tuples (commit-hash, tag ref name)
80         raw_tags = csv.reader(StringIO(data), delimiter=' ')
81         vcs_tags = []
82         for row in raw_tags:
83             row = filter(lambda f: f != '', row)
84             if row == []:
85                 continue
86             name, commit = row
87             if name == 'tip':
88                 continue
89             revision, commit_hash = commit.split(':')
90             vcs_tags.append(VCSVersion(self, commit_hash, name))
91         return vcs_tags
92 
93     def checkout(self, identifier=None):
94         super(Backend, self).checkout()
95         if not identifier:
96             identifier = 'tip'
97         retcode = self.run('hg', 'status')[0]
98         if retcode == 0:
99             self.run('hg', 'pull')
100             return self.run('hg', 'update', '-C', identifier)
101         else:
102             self.clone()
103             return self.run('hg', 'update', '-C', identifier)
104
```
--- END FILES ---

Please first localize the bug based on the issue statement, and then generate a patch according to the `git diff` format fenced by three backticks.

Here is an example:

```diff
diff --git a/examples/server_async.py b/examples/server_async.py
--- a/examples/server_async.py
+++ b/examples/server_async.py
@@ -313,4 +313,4 @@
 
 
 if __name__ == "__main__":
-    asyncio.run(run_async_server("."), debug=True)
+    asyncio.run(run_async_server(), debug=True)
diff --git a/examples/server_sync.py b/examples/server_sync.py
--- a/examples/server_sync.py
+++ b/examples/server_sync.py
@@ -313,5 +313,5 @@
 
 
 if __name__ == "__main__":
-    server = run_sync_server(".")
+    server = run_sync_server()
     server.shutdown()

```

diff --git a/readthedocs/vcs_support/backends/hg.py b/readthedocs/vcs_support/backends/hg.py
--- a/readthedocs/vcs_support/backends/hg.py
+++ b/readthedocs/vcs_support/backends/hg.py
@@ -1,6 +1,3 @@
-import csv
-from StringIO import StringIO
-
 from projects.exceptions import ProjectImportError
 from vcs_support.base import BaseVCS, VCSVersion
 
@@ -69,19 +66,24 @@
 
     def parse_tags(self, data):
         """
-        Parses output of show-ref --tags, eg:
+        Parses output of `hg tags`, eg:
+
+            tip                              278:c4b2d21db51a
+            0.2.2                            152:6b0364d98837
+            0.2.1                            117:a14b7b6ffa03
+            0.1                               50:30c2c6b3a055
+            maintenance release 1             10:f83c32fe8126
 
-        tip                              278:c4b2d21db51a
-        0.2.2                            152:6b0364d98837
-        0.2.1                            117:a14b7b6ffa03
-        0.1                               50:30c2c6b3a055
+        Into VCSVersion objects with the tag name as verbose_name and the
+        commit hash as identifier.
         """
-        # parse the lines into a list of tuples (commit-hash, tag ref name)
-        raw_tags = csv.reader(StringIO(data), delimiter=' ')
         vcs_tags = []
-        for row in raw_tags:
-            row = filter(lambda f: f != '', row)
-            if row == []:
+        tag_lines = [line.strip() for line in data.splitlines()]
+        # starting from the rhs of each line, split a single value (changeset)
+        # off at whitespace; the tag name is the string to the left of that
+        tag_pairs = [line.rsplit(None, 1) for line in tag_lines]
+        for row in tag_pairs:
+            if len(row) != 2:
                 continue
             name, commit = row
             if name == 'tip':

{"golden_diff": "diff --git a/readthedocs/vcs_support/backends/hg.py b/readthedocs/vcs_support/backends/hg.py\n--- a/readthedocs/vcs_support/backends/hg.py\n+++ b/readthedocs/vcs_support/backends/hg.py\n@@ -1,6 +1,3 @@\n-import csv\n-from StringIO import StringIO\n-\n from projects.exceptions import ProjectImportError\n from vcs_support.base import BaseVCS, VCSVersion\n \n@@ -69,19 +66,24 @@\n \n     def parse_tags(self, data):\n         \"\"\"\n-        Parses output of show-ref --tags, eg:\n+        Parses output of `hg tags`, eg:\n+\n+            tip                              278:c4b2d21db51a\n+            0.2.2                            152:6b0364d98837\n+            0.2.1                            117:a14b7b6ffa03\n+            0.1                               50:30c2c6b3a055\n+            maintenance release 1             10:f83c32fe8126\n \n-        tip                              278:c4b2d21db51a\n-        0.2.2                            152:6b0364d98837\n-        0.2.1                            117:a14b7b6ffa03\n-        0.1                               50:30c2c6b3a055\n+        Into VCSVersion objects with the tag name as verbose_name and the\n+        commit hash as identifier.\n         \"\"\"\n-        # parse the lines into a list of tuples (commit-hash, tag ref name)\n-        raw_tags = csv.reader(StringIO(data), delimiter=' ')\n         vcs_tags = []\n-        for row in raw_tags:\n-            row = filter(lambda f: f != '', row)\n-            if row == []:\n+        tag_lines = [line.strip() for line in data.splitlines()]\n+        # starting from the rhs of each line, split a single value (changeset)\n+        # off at whitespace; the tag name is the string to the left of that\n+        tag_pairs = [line.rsplit(None, 1) for line in tag_lines]\n+        for row in tag_pairs:\n+            if len(row) != 2:\n                 continue\n             name, commit = row\n             if name == 'tip':\n", "issue": "mercurial project imported from bitbucket stuck in 'Triggered' state\nThe docs for pylibftdi are set to be built (via a POST trigger) from https://bitbucket.org/codedstructure/pylibftdi, but builds (https://readthedocs.org/builds/pylibftdi/) are stuck at 'Triggered'.\n\nBased on comments in #435 I set the project up to build against a github mirror, and that worked successfully, so it seems (from #435) that this is likely an hg issue.\n\n", "before_files": [{"content": "import csv\nfrom StringIO import StringIO\n\nfrom projects.exceptions import ProjectImportError\nfrom vcs_support.base import BaseVCS, VCSVersion\n\n\nclass Backend(BaseVCS):\n    supports_tags = True\n    supports_branches = True\n    fallback_branch = 'default'\n\n    def update(self):\n        super(Backend, self).update()\n        retcode = self.run('hg', 'status')[0]\n        if retcode == 0:\n            return self.pull()\n        else:\n            return self.clone()\n\n    def pull(self):\n        pull_output = self.run('hg', 'pull')\n        if pull_output[0] != 0:\n            raise ProjectImportError(\n                (\"Failed to get code from '%s' (hg pull): %s\"\n                 % (self.repo_url, pull_output[0]))\n            )\n        update_output = self.run('hg', 'update', '-C')[0]\n        if update_output[0] != 0:\n            raise ProjectImportError(\n                (\"Failed to get code from '%s' (hg update): %s\"\n                 % (self.repo_url, pull_output[0]))\n            )\n        return update_output\n\n    def clone(self):\n        output = self.run('hg', 'clone', self.repo_url, '.')\n        if output[0] != 0:\n            raise ProjectImportError(\n                (\"Failed to get code from '%s' (hg clone): %s\"\n                 % (self.repo_url, output[0]))\n            )\n        return output\n\n    @property\n    def branches(self):\n        retcode, stdout = self.run('hg', 'branches', '-q')[:2]\n        # error (or no tags found)\n        if retcode != 0:\n            return []\n        return self.parse_branches(stdout)\n\n    def parse_branches(self, data):\n        \"\"\"\n        stable\n        default\n        \"\"\"\n\n        names = [name.lstrip() for name in data.splitlines()]\n        return [VCSVersion(self, name, name) for name in names if name]\n\n    @property\n    def tags(self):\n        retcode, stdout = self.run('hg', 'tags')[:2]\n        # error (or no tags found)\n        if retcode != 0:\n            return []\n        return self.parse_tags(stdout)\n\n    def parse_tags(self, data):\n        \"\"\"\n        Parses output of show-ref --tags, eg:\n\n        tip                              278:c4b2d21db51a\n        0.2.2                            152:6b0364d98837\n        0.2.1                            117:a14b7b6ffa03\n        0.1                               50:30c2c6b3a055\n        \"\"\"\n        # parse the lines into a list of tuples (commit-hash, tag ref name)\n        raw_tags = csv.reader(StringIO(data), delimiter=' ')\n        vcs_tags = []\n        for row in raw_tags:\n            row = filter(lambda f: f != '', row)\n            if row == []:\n                continue\n            name, commit = row\n            if name == 'tip':\n                continue\n            revision, commit_hash = commit.split(':')\n            vcs_tags.append(VCSVersion(self, commit_hash, name))\n        return vcs_tags\n\n    def checkout(self, identifier=None):\n        super(Backend, self).checkout()\n        if not identifier:\n            identifier = 'tip'\n        retcode = self.run('hg', 'status')[0]\n        if retcode == 0:\n            self.run('hg', 'pull')\n            return self.run('hg', 'update', '-C', identifier)\n        else:\n            self.clone()\n            return self.run('hg', 'update', '-C', identifier)\n", "path": "readthedocs/vcs_support/backends/hg.py"}], "after_files": [{"content": "from projects.exceptions import ProjectImportError\nfrom vcs_support.base import BaseVCS, VCSVersion\n\n\nclass Backend(BaseVCS):\n    supports_tags = True\n    supports_branches = True\n    fallback_branch = 'default'\n\n    def update(self):\n        super(Backend, self).update()\n        retcode = self.run('hg', 'status')[0]\n        if retcode == 0:\n            return self.pull()\n        else:\n            return self.clone()\n\n    def pull(self):\n        pull_output = self.run('hg', 'pull')\n        if pull_output[0] != 0:\n            raise ProjectImportError(\n                (\"Failed to get code from '%s' (hg pull): %s\"\n                 % (self.repo_url, pull_output[0]))\n            )\n        update_output = self.run('hg', 'update', '-C')[0]\n        if update_output[0] != 0:\n            raise ProjectImportError(\n                (\"Failed to get code from '%s' (hg update): %s\"\n                 % (self.repo_url, pull_output[0]))\n            )\n        return update_output\n\n    def clone(self):\n        output = self.run('hg', 'clone', self.repo_url, '.')\n        if output[0] != 0:\n            raise ProjectImportError(\n                (\"Failed to get code from '%s' (hg clone): %s\"\n                 % (self.repo_url, output[0]))\n            )\n        return output\n\n    @property\n    def branches(self):\n        retcode, stdout = self.run('hg', 'branches', '-q')[:2]\n        # error (or no tags found)\n        if retcode != 0:\n            return []\n        return self.parse_branches(stdout)\n\n    def parse_branches(self, data):\n        \"\"\"\n        stable\n        default\n        \"\"\"\n\n        names = [name.lstrip() for name in data.splitlines()]\n        return [VCSVersion(self, name, name) for name in names if name]\n\n    @property\n    def tags(self):\n        retcode, stdout = self.run('hg', 'tags')[:2]\n        # error (or no tags found)\n        if retcode != 0:\n            return []\n        return self.parse_tags(stdout)\n\n    def parse_tags(self, data):\n        \"\"\"\n        Parses output of `hg tags`, eg:\n\n            tip                              278:c4b2d21db51a\n            0.2.2                            152:6b0364d98837\n            0.2.1                            117:a14b7b6ffa03\n            0.1                               50:30c2c6b3a055\n            maintenance release 1             10:f83c32fe8126\n\n        Into VCSVersion objects with the tag name as verbose_name and the\n        commit hash as identifier.\n        \"\"\"\n        vcs_tags = []\n        tag_lines = [line.strip() for line in data.splitlines()]\n        # starting from the rhs of each line, split a single value (changeset)\n        # off at whitespace; the tag name is the string to the left of that\n        tag_pairs = [line.rsplit(None, 1) for line in tag_lines]\n        for row in tag_pairs:\n            if len(row) != 2:\n                continue\n            name, commit = row\n            if name == 'tip':\n                continue\n            revision, commit_hash = commit.split(':')\n            vcs_tags.append(VCSVersion(self, commit_hash, name))\n        return vcs_tags\n\n    def checkout(self, identifier=None):\n        super(Backend, self).checkout()\n        if not identifier:\n            identifier = 'tip'\n        retcode = self.run('hg', 'status')[0]\n        if retcode == 0:\n            self.run('hg', 'pull')\n            return self.run('hg', 'update', '-C', identifier)\n        else:\n            self.clone()\n            return self.run('hg', 'update', '-C', identifier)\n", "path": "readthedocs/vcs_support/backends/hg.py"}]}