7 files changed, 1112 insertions, 0 deletions
diff --git a/testing/web-platform/update/__init__.py b/testing/web-platform/update/__init__.py
new file mode 100644
index 0000000000..47c6d36d95
--- /dev/null
+++ b/testing/web-platform/update/__init__.py
@@ -0,0 +1,40 @@
+#!/usr/bin/env python
+#
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+import imp
+import os
+import sys
+
+from mozlog import structuredlog
+
+here = os.path.split(__file__)[0]
+
+imp.load_source(
+    "localpaths", os.path.join(here, os.pardir, "tests", "tools", "localpaths.py")
+)
+
+from wptrunner.update import WPTUpdate, setup_logging
+from wptrunner.update.base import exit_unclean
+
+from . import updatecommandline
+from .update import UpdateRunner
+
+
+def run_update(logger, **kwargs):
+    updater = WPTUpdate(logger, runner_cls=UpdateRunner, **kwargs)
+    return updater.run()
+
+
+if __name__ == "__main__":
+    args = updatecommandline.parse_args()
+    logger = setup_logging(args, {"mach": sys.stdout})
+    assert structuredlog.get_default_logger() is not None
+
+    rv = run_update(logger, **args)
+    if rv is exit_unclean:
+        sys.exit(1)
+    else:
+        sys.exit(0)
diff --git a/testing/web-platform/update/fetchlogs.py b/testing/web-platform/update/fetchlogs.py
new file mode 100644
index 0000000000..dc8ebae059
--- /dev/null
+++ b/testing/web-platform/update/fetchlogs.py
@@ -0,0 +1,123 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+import argparse
+import os
+
+import requests
+import urlparse
+
+treeherder_base = "https://treeherder.mozilla.org/"
+
+"""Simple script for downloading structured logs from treeherder.
+
+For the moment this is specialised to work with web-platform-tests
+logs; in due course it should move somewhere generic and get hooked
+up to mach or similar"""
+
+# Interpretation of the "job" list from
+# https://github.com/mozilla/treeherder-service/blob/master/treeherder/webapp/api/utils.py#L18
+
+
+def create_parser():
+    parser = argparse.ArgumentParser()
+    parser.add_argument("branch", action="store", help="Branch on which jobs ran")
+    parser.add_argument("commit", action="store", help="Commit hash for push")
+
+    return parser
+
+
+def download(url, prefix, dest, force_suffix=True):
+    if dest is None:
+        dest = "."
+
+    if prefix and not force_suffix:
+        name = os.path.join(dest, prefix + ".log")
+    else:
+        name = None
+    counter = 0
+
+    while not name or os.path.exists(name):
+        counter += 1
+        sep = "" if not prefix else "-"
+        name = os.path.join(dest, prefix + sep + str(counter) + ".log")
+
+    with open(name, "wb") as f:
+        resp = requests.get(url, stream=True)
+        for chunk in resp.iter_content(1024):
+            f.write(chunk)
+
+
+def fetch_json(url, params=None):
+    headers = {
+        "Accept": "application/json",
+        "User-Agent": "wpt-fetchlogs",
+    }
+    response = requests.get(url=url, params=params, headers=headers, timeout=30)
+    response.raise_for_status()
+    return response.json()
+
+
+def get_blobber_url(branch, job):
+    job_guid = job["job_guid"]
+    artifact_url = urlparse.urljoin(treeherder_base, "/api/jobdetail/")
+    artifact_params = {
+        "job_guid": job_guid,
+    }
+    job_data = fetch_json(artifact_url, params=artifact_params)
+
+    if job_data:
+        try:
+            for item in job_data["results"]:
+                if item["value"] == "wpt_raw.log" or item["value"] == "log_raw.log":
+                    return item["url"]
+        except Exception:
+            return None
+
+
+def get_structured_logs(branch, commit, dest=None):
+    resultset_url = urlparse.urljoin(
+        treeherder_base, "/api/project/%s/resultset/" % branch
+    )
+    resultset_params = {
+        "revision": commit,
+    }
+    revision_data = fetch_json(resultset_url, params=resultset_params)
+    result_set = revision_data["results"][0]["id"]
+
+    jobs_url = urlparse.urljoin(treeherder_base, "/api/project/%s/jobs/" % branch)
+    jobs_params = {
+        "result_set_id": result_set,
+        "count": 2000,
+        "exclusion_profile": "false",
+    }
+    job_data = fetch_json(jobs_url, params=jobs_params)
+
+    tasks = []
+
+    for result in job_data["results"]:
+        job_type_name = result["job_type_name"]
+        if (
+            job_type_name.startswith("W3C Web Platform")
+            or job_type_name.startswith("test-")
+            and "-web-platform-tests-" in job_type_name
+        ):
+            url = get_blobber_url(branch, result)
+            if url:
+                prefix = result["platform"]  # platform
+                tasks.append((url, prefix, None))
+
+    for task in tasks:
+        download(*task)
+
+
+def main():
+    parser = create_parser()
+    args = parser.parse_args()
+
+    get_structured_logs(args.branch, args.commit)
+
+
+if __name__ == "__main__":
+    main()
diff --git a/testing/web-platform/update/github.py b/testing/web-platform/update/github.py
new file mode 100644
index 0000000000..819da9ea1a
--- /dev/null
+++ b/testing/web-platform/update/github.py
@@ -0,0 +1,169 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+import json
+
+from six.moves.urllib.parse import urljoin
+
+requests = None
+
+
+class GitHubError(Exception):
+    def __init__(self, status, data):
+        self.status = status
+        self.data = data
+
+
+class GitHub(object):
+    url_base = "https://api.github.com"
+
+    def __init__(self, token):
+        # Defer the import of requests since it isn't installed by default
+        global requests
+        if requests is None:
+            import requests
+
+        self.headers = {"Accept": "application/vnd.github.v3+json"}
+        self.auth = (token, "x-oauth-basic")
+
+    def get(self, path):
+        return self._request("GET", path)
+
+    def post(self, path, data):
+        return self._request("POST", path, data=data)
+
+    def put(self, path, data, headers=None):
+        return self._request("PUT", path, data=data, headers=headers)
+
+    def _request(self, method, path, data=None, headers=None):
+        url = urljoin(self.url_base, path)
+
+        headers_ = self.headers
+        if headers is not None:
+            headers_.update(headers)
+        kwargs = {"headers": headers_, "auth": self.auth}
+        if data is not None:
+            kwargs["data"] = json.dumps(data)
+
+        resp = requests.request(method, url, **kwargs)
+
+        if 200 <= resp.status_code < 300:
+            return resp.json()
+        else:
+            print(method, path, resp.status_code, resp.json())
+            raise GitHubError(resp.status_code, resp.json())
+
+    def repo(self, owner, name):
+        """GitHubRepo for a particular repository.
+
+        :param owner: String repository owner
+        :param name: String repository name
+        """
+        return GitHubRepo.from_name(self, owner, name)
+
+
+class GitHubRepo(object):
+    def __init__(self, github, data):
+        """Object respresenting a GitHub respoitory"""
+        self.gh = github
+        self.owner = data["owner"]
+        self.name = data["name"]
+        self.url = data["ssh_url"]
+        self._data = data
+
+    @classmethod
+    def from_name(cls, github, owner, name):
+        data = github.get("/repos/%s/%s" % (owner, name))
+        return cls(github, data)
+
+    @property
+    def url_base(self):
+        return "/repos/%s/" % (self._data["full_name"])
+
+    def create_pr(self, title, head, base, body):
+        """Create a Pull Request in the repository
+
+        :param title: Pull Request title
+        :param head: ref to the HEAD of the PR branch.
+        :param base: ref to the base branch for the Pull Request
+        :param body: Description of the PR
+        """
+        return PullRequest.create(self, title, head, base, body)
+
+    def load_pr(self, number):
+        """Load an existing Pull Request by number.
+
+        :param number: Pull Request number
+        """
+        return PullRequest.from_number(self, number)
+
+    def path(self, suffix):
+        return urljoin(self.url_base, suffix)
+
+
+class PullRequest(object):
+    def __init__(self, repo, data):
+        """Object representing a Pull Request"""
+
+        self.repo = repo
+        self._data = data
+        self.number = data["number"]
+        self.title = data["title"]
+        self.base = data["base"]["ref"]
+        self.base = data["head"]["ref"]
+        self._issue = None
+
+    @classmethod
+    def from_number(cls, repo, number):
+        data = repo.gh.get(repo.path("pulls/%i" % number))
+        return cls(repo, data)
+
+    @classmethod
+    def create(cls, repo, title, head, base, body):
+        data = repo.gh.post(
+            repo.path("pulls"),
+            {"title": title, "head": head, "base": base, "body": body},
+        )
+        return cls(repo, data)
+
+    def path(self, suffix):
+        return urljoin(self.repo.path("pulls/%i/" % self.number), suffix)
+
+    @property
+    def issue(self):
+        """Issue related to the Pull Request"""
+        if self._issue is None:
+            self._issue = Issue.from_number(self.repo, self.number)
+        return self._issue
+
+    def merge(self):
+        """Merge the Pull Request into its base branch."""
+        self.repo.gh.put(
+            self.path("merge"),
+            {"merge_method": "merge"},
+            headers={"Accept": "application/vnd.github.polaris-preview+json"},
+        )
+
+
+class Issue(object):
+    def __init__(self, repo, data):
+        """Object representing a GitHub Issue"""
+        self.repo = repo
+        self._data = data
+        self.number = data["number"]
+
+    @classmethod
+    def from_number(cls, repo, number):
+        data = repo.gh.get(repo.path("issues/%i" % number))
+        return cls(repo, data)
+
+    def path(self, suffix):
+        return urljoin(self.repo.path("issues/%i/" % self.number), suffix)
+
+    def add_comment(self, message):
+        """Add a comment to the issue
+
+        :param message: The text of the comment
+        """
+        self.repo.gh.post(self.path("comments"), {"body": message})
diff --git a/testing/web-platform/update/tree.py b/testing/web-platform/update/tree.py
new file mode 100644
index 0000000000..48197c74b6
--- /dev/null
+++ b/testing/web-platform/update/tree.py
@@ -0,0 +1,196 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+import re
+import tempfile
+
+from wptrunner import update as wptupdate
+from wptrunner.update.tree import Commit, CommitMessage, get_unique_name
+
+
+class HgTree(wptupdate.tree.HgTree):
+    def __init__(self, *args, **kwargs):
+        self.commit_cls = kwargs.pop("commit_cls", Commit)
+        wptupdate.tree.HgTree.__init__(self, *args, **kwargs)
+
+    # TODO: The extra methods for upstreaming patches from a
+    # hg checkout
+
+
+class GitTree(wptupdate.tree.GitTree):
+    def __init__(self, *args, **kwargs):
+        """Extension of the basic GitTree with extra methods for
+        transfering patches"""
+        commit_cls = kwargs.pop("commit_cls", Commit)
+        wptupdate.tree.GitTree.__init__(self, *args, **kwargs)
+        self.commit_cls = commit_cls
+
+    def rev_from_hg(self, rev):
+        return self.git("cinnabar", "hg2git", rev).strip()
+
+    def rev_to_hg(self, rev):
+        return self.git("cinnabar", "git2hg", rev).strip()
+
+    def create_branch(self, name, ref=None):
+        """Create a named branch,
+
+        :param name: String representing the branch name.
+        :param ref: None to use current HEAD or rev that the branch should point to"""
+
+        args = []
+        if ref is not None:
+            if hasattr(ref, "sha1"):
+                ref = ref.sha1
+            args.append(ref)
+        self.git("branch", name, *args)
+
+    def commits_by_message(self, message, path=None):
+        """List of commits with messages containing a given string.
+
+        :param message: The string that must be contained in the message.
+        :param path: Path to a file or directory the commit touches
+        """
+        args = ["--pretty=format:%H", "--reverse", "-z", "--grep=%s" % message]
+        if path is not None:
+            args.append("--")
+            args.append(path)
+        data = self.git("log", *args)
+        return [self.commit_cls(self, sha1) for sha1 in data.split("\0")]
+
+    def log(self, base_commit=None, path=None):
+        """List commits touching a certian path from a given base commit.
+
+        :base_param commit: Commit object for the base commit from which to log
+        :param path: Path that the commits must touch
+        """
+        args = ["--pretty=format:%H", "--reverse", "-z"]
+        if base_commit is not None:
+            args.append("%s.." % base_commit.sha1)
+        if path is not None:
+            args.append("--")
+            args.append(path)
+        data = self.git("log", *args)
+        return [self.commit_cls(self, sha1) for sha1 in data.split("\0") if sha1]
+
+    def import_patch(self, patch):
+        """Import a patch file into the tree and commit it
+
+        :param patch: a Patch object containing the patch to import
+        """
+
+        with tempfile.NamedTemporaryFile() as f:
+            f.write(patch.diff)
+            f.flush()
+            f.seek(0)
+            self.git("apply", "--index", f.name)
+        self.git("commit", "-m", patch.message.text, "--author=%s" % patch.full_author)
+
+    def rebase(self, ref, continue_rebase=False):
+        """Rebase the current branch onto another commit.
+
+        :param ref: A Commit object for the commit to rebase onto
+        :param continue_rebase: Continue an in-progress rebase"""
+        if continue_rebase:
+            args = ["--continue"]
+        else:
+            if hasattr(ref, "sha1"):
+                ref = ref.sha1
+            args = [ref]
+        self.git("rebase", *args)
+
+    def push(self, remote, local_ref, remote_ref, force=False):
+        """Push local changes to a remote.
+
+        :param remote: URL of the remote to push to
+        :param local_ref: Local branch to push
+        :param remote_ref: Name of the remote branch to push to
+        :param force: Do a force push
+        """
+        args = []
+        if force:
+            args.append("-f")
+        args.extend([remote, "%s:%s" % (local_ref, remote_ref)])
+        self.git("push", *args)
+
+    def unique_branch_name(self, prefix):
+        """Get an unused branch name in the local tree
+
+        :param prefix: Prefix to use at the start of the branch name"""
+        branches = [
+            ref[len("refs/heads/") :]
+            for sha1, ref in self.list_refs()
+            if ref.startswith("refs/heads/")
+        ]
+        return get_unique_name(branches, prefix)
+
+
+class Patch(object):
+    def __init__(self, author, email, message, diff):
+        self.author = author
+        self.email = email
+        if isinstance(message, CommitMessage):
+            self.message = message
+        else:
+            self.message = GeckoCommitMessage(message)
+        self.diff = diff
+
+    def __repr__(self):
+        return "<Patch (%s)>" % self.message.full_summary
+
+    @property
+    def full_author(self):
+        return "%s <%s>" % (self.author, self.email)
+
+    @property
+    def empty(self):
+        return bool(self.diff.strip())
+
+
+class GeckoCommitMessage(CommitMessage):
+    """Commit message following the Gecko conventions for identifying bug number
+    and reviewer"""
+
+    # c.f. http://hg.mozilla.org/hgcustom/version-control-tools/file/tip/hghooks/mozhghooks/commit-message.py # noqa E501
+    # which has the regexps that are actually enforced by the VCS hooks. These are
+    # slightly different because we need to parse out specific parts of the message rather
+    # than just enforce a general pattern.
+
+    _bug_re = re.compile(
+        "^Bug (\d+)[^\w]*(?:Part \d+[^\w]*)?(.*?)\s*(?:r=(\w*))?$", re.IGNORECASE
+    )
+
+    _backout_re = re.compile(
+        "^(?:Back(?:ing|ed)\s+out)|Backout|(?:Revert|(?:ed|ing))", re.IGNORECASE
+    )
+    _backout_sha1_re = re.compile("(?:\s|\:)(0-9a-f){12}")
+
+    def _parse_message(self):
+        CommitMessage._parse_message(self)
+
+        if self._backout_re.match(self.full_summary):
+            self.backouts = self._backout_re.findall(self.full_summary)
+        else:
+            self.backouts = []
+
+        m = self._bug_re.match(self.full_summary)
+        if m is not None:
+            self.bug, self.summary, self.reviewer = m.groups()
+        else:
+            self.bug, self.summary, self.reviewer = None, self.full_summary, None
+
+
+class GeckoCommit(Commit):
+    msg_cls = GeckoCommitMessage
+
+    def export_patch(self, path=None):
+        """Convert a commit in the tree to a Patch with the bug number and
+        reviewer stripped from the message"""
+        args = ["--binary", "--patch", "--format=format:", "%s" % (self.sha1,)]
+        if path is not None:
+            args.append("--")
+            args.append(path)
+
+        diff = self.git("show", *args)
+
+        return Patch(self.author, self.email, self.message, diff)
diff --git a/testing/web-platform/update/update.py b/testing/web-platform/update/update.py
new file mode 100644
index 0000000000..68d3293fb7
--- /dev/null
+++ b/testing/web-platform/update/update.py
@@ -0,0 +1,51 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+import os
+
+from wptrunner.update.base import Step, StepRunner
+from wptrunner.update.tree import NoVCSTree
+from wptrunner.update.update import (
+    LoadConfig,
+    RemoveObsolete,
+    SyncFromUpstream,
+    UpdateMetadata,
+)
+
+from .tree import GeckoCommit, GitTree, HgTree
+from .upstream import SyncToUpstream
+
+
+class LoadTrees(Step):
+    """Load gecko tree and sync tree containing web-platform-tests"""
+
+    provides = ["local_tree", "sync_tree"]
+
+    def create(self, state):
+        if os.path.exists(state.sync["path"]):
+            sync_tree = GitTree(root=state.sync["path"])
+        else:
+            sync_tree = None
+
+        if GitTree.is_type():
+            local_tree = GitTree(commit_cls=GeckoCommit)
+        elif HgTree.is_type():
+            local_tree = HgTree(commit_cls=GeckoCommit)
+        else:
+            local_tree = NoVCSTree()
+
+        state.update({"local_tree": local_tree, "sync_tree": sync_tree})
+
+
+class UpdateRunner(StepRunner):
+    """Overall runner for updating web-platform-tests in Gecko."""
+
+    steps = [
+        LoadConfig,
+        LoadTrees,
+        SyncToUpstream,
+        SyncFromUpstream,
+        RemoveObsolete,
+        UpdateMetadata,
+    ]
diff --git a/testing/web-platform/update/updatecommandline.py b/testing/web-platform/update/updatecommandline.py
new file mode 100644
index 0000000000..9e8cd8673e
--- /dev/null
+++ b/testing/web-platform/update/updatecommandline.py
@@ -0,0 +1,58 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+
+def create_parser():
+    from wptrunner import wptcommandline
+
+    parser = wptcommandline.create_parser_update()
+    parser.add_argument(
+        "--upstream",
+        dest="upstream",
+        action="store_true",
+        default=None,
+        help="Push local changes to upstream repository even when not syncing",
+    )
+    parser.add_argument(
+        "--no-upstream",
+        dest="upstream",
+        action="store_false",
+        default=None,
+        help="Dont't push local changes to upstream repository when syncing",
+    )
+    parser.add_argument(
+        "--token-file",
+        action="store",
+        type=wptcommandline.abs_path,
+        help="Path to file containing github token",
+    )
+    parser.add_argument("--token", action="store", help="GitHub token to use")
+    return parser
+
+
+def check_args(kwargs):
+    from wptrunner import wptcommandline
+
+    kwargs = wptcommandline.check_args_update(kwargs)
+    kwargs["upstream"] = (
+        kwargs["upstream"] if kwargs["upstream"] is not None else kwargs["sync"]
+    )
+
+    if kwargs["upstream"]:
+        if kwargs["rev"]:
+            raise ValueError("Setting --rev with --upstream isn't supported")
+        if kwargs["token"] is None:
+            if kwargs["token_file"] is None:
+                raise ValueError("Must supply either a token file or a token")
+            with open(kwargs["token_file"]) as f:
+                token = f.read().strip()
+                kwargs["token"] = token
+    del kwargs["token_file"]
+    return kwargs
+
+
+def parse_args():
+    parser = create_parser()
+    kwargs = vars(parser.parse_args())
+    return check_args(kwargs)
diff --git a/testing/web-platform/update/upstream.py b/testing/web-platform/update/upstream.py
new file mode 100644
index 0000000000..21efc72a13
--- /dev/null
+++ b/testing/web-platform/update/upstream.py
@@ -0,0 +1,475 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+import os
+import re
+import subprocess
+import sys
+import tempfile
+
+from six.moves import input
+from six.moves.urllib import parse as urlparse
+from wptrunner.update.base import Step, StepRunner, exit_clean, exit_unclean
+from wptrunner.update.tree import get_unique_name
+
+from .github import GitHub
+from .tree import Commit, GitTree, Patch
+
+
+def rewrite_patch(patch, strip_dir):
+    """Take a Patch and convert to a different repository by stripping a prefix from the
+    file paths. Also rewrite the message to remove the bug number and reviewer, but add
+    a bugzilla link in the summary.
+
+    :param patch: the Patch to convert
+    :param strip_dir: the path prefix to remove
+    """
+
+    if not strip_dir.startswith("/"):
+        strip_dir = "/%s" % strip_dir
+
+    new_diff = []
+    line_starts = [
+        ("diff ", True),
+        ("+++ ", True),
+        ("--- ", True),
+        ("rename from ", False),
+        ("rename to ", False),
+    ]
+    for line in patch.diff.split("\n"):
+        for start, leading_slash in line_starts:
+            strip = strip_dir if leading_slash else strip_dir[1:]
+            if line.startswith(start):
+                new_diff.append(line.replace(strip, "").encode("utf8"))
+                break
+        else:
+            new_diff.append(line)
+
+    new_diff = "\n".join(new_diff)
+
+    assert new_diff != patch
+
+    return Patch(patch.author, patch.email, rewrite_message(patch), new_diff)
+
+
+def rewrite_message(patch):
+    if patch.message.bug is not None:
+        return "\n".join(
+            [
+                patch.message.summary,
+                patch.message.body,
+                "",
+                "Upstreamed from https://bugzilla.mozilla.org/show_bug.cgi?id=%s [ci skip]"
+                % patch.message.bug,  # noqa E501
+            ]
+        )
+
+    return "\n".join(
+        [patch.message.full_summary, "%s\n[ci skip]\n" % patch.message.body]
+    )
+
+
+class SyncToUpstream(Step):
+    """Sync local changes to upstream"""
+
+    def create(self, state):
+        if not state.kwargs["upstream"]:
+            return
+
+        if not isinstance(state.local_tree, GitTree):
+            self.logger.error("Cannot sync with upstream from a non-Git checkout.")
+            return exit_clean
+
+        try:
+            import requests  # noqa F401
+        except ImportError:
+            self.logger.error(
+                "Upstream sync requires the requests module to be installed"
+            )
+            return exit_clean
+
+        if not state.sync_tree:
+            os.makedirs(state.sync["path"])
+            state.sync_tree = GitTree(root=state.sync["path"])
+
+        kwargs = state.kwargs
+        with state.push(
+            ["local_tree", "sync_tree", "tests_path", "metadata_path", "sync"]
+        ):
+            state.token = kwargs["token"]
+            runner = SyncToUpstreamRunner(self.logger, state)
+            runner.run()
+
+
+class GetLastSyncData(Step):
+    """Find the gecko commit at which we last performed a sync with upstream and the upstream
+    commit that was synced."""
+
+    provides = ["sync_data_path", "last_sync_commit", "old_upstream_rev"]
+
+    def create(self, state):
+        self.logger.info("Looking for last sync commit")
+        state.sync_data_path = os.path.join(state.metadata_path, "mozilla-sync")
+        items = {}
+        with open(state.sync_data_path) as f:
+            for line in f.readlines():
+                key, value = [item.strip() for item in line.split(":", 1)]
+                items[key] = value
+
+        state.last_sync_commit = Commit(
+            state.local_tree, state.local_tree.rev_from_hg(items["local"])
+        )
+        state.old_upstream_rev = items["upstream"]
+
+        if not state.local_tree.contains_commit(state.last_sync_commit):
+            self.logger.error(
+                "Could not find last sync commit %s" % state.last_sync_commit.sha1
+            )
+            return exit_clean
+
+        self.logger.info(
+            "Last sync to web-platform-tests happened in %s"
+            % state.last_sync_commit.sha1
+        )
+
+
+class CheckoutBranch(Step):
+    """Create a branch in the sync tree pointing at the last upstream sync commit
+    and check it out"""
+
+    provides = ["branch"]
+
+    def create(self, state):
+        self.logger.info("Updating sync tree from %s" % state.sync["remote_url"])
+        state.branch = state.sync_tree.unique_branch_name(
+            "outbound_update_%s" % state.old_upstream_rev
+        )
+        state.sync_tree.update(
+            state.sync["remote_url"], state.sync["branch"], state.branch
+        )
+        state.sync_tree.checkout(state.old_upstream_rev, state.branch, force=True)
+
+
+class GetBaseCommit(Step):
+    """Find the latest upstream commit on the branch that we are syncing with"""
+
+    provides = ["base_commit"]
+
+    def create(self, state):
+        state.base_commit = state.sync_tree.get_remote_sha1(
+            state.sync["remote_url"], state.sync["branch"]
+        )
+        self.logger.debug("New base commit is %s" % state.base_commit.sha1)
+
+
+class LoadCommits(Step):
+    """Get a list of commits in the gecko tree that need to be upstreamed"""
+
+    provides = ["source_commits", "has_backouts"]
+
+    def create(self, state):
+        state.source_commits = state.local_tree.log(
+            state.last_sync_commit, state.tests_path
+        )
+
+        update_regexp = re.compile(
+            "Bug \d+ - Update web-platform-tests to revision [0-9a-f]{40}"
+        )
+
+        state.has_backouts = False
+
+        for i, commit in enumerate(state.source_commits[:]):
+            if update_regexp.match(commit.message.text):
+                # This is a previous update commit so ignore it
+                state.source_commits.remove(commit)
+                continue
+
+            elif commit.message.backouts:
+                # TODO: Add support for collapsing backouts
+                state.has_backouts = True
+
+            elif not commit.message.bug:
+                self.logger.error(
+                    "Commit %i (%s) doesn't have an associated bug number."
+                    % (i + 1, commit.sha1)
+                )
+                return exit_unclean
+
+        self.logger.debug("Source commits: %s" % state.source_commits)
+
+
+class SelectCommits(Step):
+    """Provide a UI to select which commits to upstream"""
+
+    def create(self, state):
+        while True:
+            commits = state.source_commits[:]
+            for i, commit in enumerate(commits):
+                print("{}:\t{}".format(i, commit.message.summary))
+
+            remove = input(
+                "Provide a space-separated list of any commits numbers "
+                "to remove from the list to upstream:\n"
+            ).strip()
+            remove_idx = set()
+            for item in remove.split(" "):
+                try:
+                    item = int(item)
+                except ValueError:
+                    continue
+                if item < 0 or item >= len(commits):
+                    continue
+                remove_idx.add(item)
+
+            keep_commits = [
+                (i, cmt) for i, cmt in enumerate(commits) if i not in remove_idx
+            ]
+            # TODO: consider printed removed commits
+            print("Selected the following commits to keep:")
+            for i, commit in keep_commits:
+                print("{}:\t{}".format(i, commit.message.summary))
+            confirm = input("Keep the above commits? y/n\n").strip().lower()
+
+            if confirm == "y":
+                state.source_commits = [item[1] for item in keep_commits]
+                break
+
+
+class MovePatches(Step):
+    """Convert gecko commits into patches against upstream and commit these to the sync tree."""
+
+    provides = ["commits_loaded"]
+
+    def create(self, state):
+        if not hasattr(state, "commits_loaded"):
+            state.commits_loaded = 0
+
+        strip_path = os.path.relpath(state.tests_path, state.local_tree.root)
+        self.logger.debug("Stripping patch %s" % strip_path)
+
+        if not hasattr(state, "patch"):
+            state.patch = None
+
+        for commit in state.source_commits[state.commits_loaded :]:
+            i = state.commits_loaded + 1
+            self.logger.info("Moving commit %i: %s" % (i, commit.message.full_summary))
+            stripped_patch = None
+            if state.patch:
+                filename, stripped_patch = state.patch
+                if not os.path.exists(filename):
+                    stripped_patch = None
+                else:
+                    with open(filename) as f:
+                        stripped_patch.diff = f.read()
+            state.patch = None
+            if not stripped_patch:
+                patch = commit.export_patch(state.tests_path)
+                stripped_patch = rewrite_patch(patch, strip_path)
+            if not stripped_patch.diff:
+                self.logger.info("Skipping empty patch")
+                state.commits_loaded = i
+                continue
+            try:
+                state.sync_tree.import_patch(stripped_patch)
+            except Exception:
+                with tempfile.NamedTemporaryFile(delete=False, suffix=".diff") as f:
+                    f.write(stripped_patch.diff)
+                    print(
+                        """Patch failed to apply. Diff saved in {}
+Fix this file so it applies and run with --continue""".format(
+                            f.name
+                        )
+                    )
+                    state.patch = (f.name, stripped_patch)
+                    print(state.patch)
+                sys.exit(1)
+            state.commits_loaded = i
+        input("Check for differences with upstream")
+
+
+class RebaseCommits(Step):
+    """Rebase commits from the current branch on top of the upstream destination branch.
+
+    This step is particularly likely to fail if the rebase generates merge conflicts.
+    In that case the conflicts can be fixed up locally and the sync process restarted
+    with --continue.
+    """
+
+    def create(self, state):
+        self.logger.info("Rebasing local commits")
+        continue_rebase = False
+        # Check if there's a rebase in progress
+        if os.path.exists(
+            os.path.join(state.sync_tree.root, ".git", "rebase-merge")
+        ) or os.path.exists(os.path.join(state.sync_tree.root, ".git", "rebase-apply")):
+            continue_rebase = True
+
+        try:
+            state.sync_tree.rebase(state.base_commit, continue_rebase=continue_rebase)
+        except subprocess.CalledProcessError:
+            self.logger.info(
+                "Rebase failed, fix merge and run %s again with --continue"
+                % sys.argv[0]
+            )
+            raise
+        self.logger.info("Rebase successful")
+
+
+class CheckRebase(Step):
+    """Check if there are any commits remaining after rebase"""
+
+    provides = ["rebased_commits"]
+
+    def create(self, state):
+        state.rebased_commits = state.sync_tree.log(state.base_commit)
+        if not state.rebased_commits:
+            self.logger.info("Nothing to upstream, exiting")
+            return exit_clean
+
+
+class MergeUpstream(Step):
+    """Run steps to push local commits as seperate PRs and merge upstream."""
+
+    provides = ["merge_index", "gh_repo"]
+
+    def create(self, state):
+        gh = GitHub(state.token)
+        if "merge_index" not in state:
+            state.merge_index = 0
+
+        org, name = urlparse.urlsplit(state.sync["remote_url"]).path[1:].split("/")
+        if name.endswith(".git"):
+            name = name[:-4]
+        state.gh_repo = gh.repo(org, name)
+        for commit in state.rebased_commits[state.merge_index :]:
+            with state.push(["gh_repo", "sync_tree"]):
+                state.commit = commit
+                pr_merger = PRMergeRunner(self.logger, state)
+                rv = pr_merger.run()
+                if rv is not None:
+                    return rv
+            state.merge_index += 1
+
+
+class UpdateLastSyncData(Step):
+    """Update the gecko commit at which we last performed a sync with upstream."""
+
+    provides = []
+
+    def create(self, state):
+        self.logger.info("Updating last sync commit")
+        data = {
+            "local": state.local_tree.rev_to_hg(state.local_tree.rev),
+            "upstream": state.sync_tree.rev,
+        }
+        with open(state.sync_data_path, "w") as f:
+            for key, value in data.iteritems():
+                f.write("%s: %s\n" % (key, value))
+        # This gets added to the patch later on
+
+
+class MergeLocalBranch(Step):
+    """Create a local branch pointing at the commit to upstream"""
+
+    provides = ["local_branch"]
+
+    def create(self, state):
+        branch_prefix = "sync_%s" % state.commit.sha1
+        local_branch = state.sync_tree.unique_branch_name(branch_prefix)
+
+        state.sync_tree.create_branch(local_branch, state.commit)
+        state.local_branch = local_branch
+
+
+class MergeRemoteBranch(Step):
+    """Get an unused remote branch name to use for the PR"""
+
+    provides = ["remote_branch"]
+
+    def create(self, state):
+        remote_branch = "sync_%s" % state.commit.sha1
+        branches = [
+            ref[len("refs/heads/") :]
+            for sha1, ref in state.sync_tree.list_remote(state.gh_repo.url)
+            if ref.startswith("refs/heads")
+        ]
+        state.remote_branch = get_unique_name(branches, remote_branch)
+
+
+class PushUpstream(Step):
+    """Push local branch to remote"""
+
+    def create(self, state):
+        self.logger.info("Pushing commit upstream")
+        state.sync_tree.push(state.gh_repo.url, state.local_branch, state.remote_branch)
+
+
+class CreatePR(Step):
+    """Create a PR for the remote branch"""
+
+    provides = ["pr"]
+
+    def create(self, state):
+        self.logger.info("Creating a PR")
+        commit = state.commit
+        state.pr = state.gh_repo.create_pr(
+            commit.message.full_summary,
+            state.remote_branch,
+            "master",
+            commit.message.body if commit.message.body else "",
+        )
+
+
+class PRAddComment(Step):
+    """Add an issue comment indicating that the code has been reviewed already"""
+
+    def create(self, state):
+        state.pr.issue.add_comment("Code reviewed upstream.")
+
+
+class MergePR(Step):
+    """Merge the PR"""
+
+    def create(self, state):
+        self.logger.info("Merging PR")
+        state.pr.merge()
+
+
+class PRDeleteBranch(Step):
+    """Delete the remote branch"""
+
+    def create(self, state):
+        self.logger.info("Deleting remote branch")
+        state.sync_tree.push(state.gh_repo.url, "", state.remote_branch)
+
+
+class SyncToUpstreamRunner(StepRunner):
+    """Runner for syncing local changes to upstream"""
+
+    steps = [
+        GetLastSyncData,
+        CheckoutBranch,
+        GetBaseCommit,
+        LoadCommits,
+        SelectCommits,
+        MovePatches,
+        RebaseCommits,
+        CheckRebase,
+        MergeUpstream,
+        UpdateLastSyncData,
+    ]
+
+
+class PRMergeRunner(StepRunner):
+    """(Sub)Runner for creating and merging a PR"""
+
+    steps = [
+        MergeLocalBranch,
+        MergeRemoteBranch,
+        PushUpstream,
+        CreatePR,
+        PRAddComment,
+        MergePR,
+        PRDeleteBranch,
+    ]