WPT sync is busted

[jdm]

Error running mach:
    ['update-wpt', '--sync', '--no-upstream', '--patch']
The error occurred in code that was called by the mach command. This is either
a bug in the called code itself or in the way that mach is calling it.
You can invoke |./mach busted| to check if this issue is already on file. If it
isn't, please use |./mach busted file| to report it. If |./mach busted| is
misbehaving, you can also inspect the dependencies of bug 1543241.
If filing a bug, please include the full output of mach, including this error
message.
The details of the failure are as follows:
IOError: [Errno 2] No such file or directory: u'/element-timing/observe-svg-image.html'
  File "/repo/python/servo/testing_commands.py", line 514, in update_wpt
    return run_globals["update_tests"](**kwargs)
  File "/repo/tests/wpt/update.py", line 23, in update_tests
    rv = update.run_update(logger, **kwargs)
  File "/repo/tests/wpt/update/__init__.py", line 26, in run_update
    return updater.run()
  File "/repo/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/update/update.py", line 184, in run
    rv = update_runner.run()
  File "/repo/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/update/base.py", line 61, in run
    rv = step(self.logger).run(step_index, self.state)
  File "/repo/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/update/base.py", line 32, in run
    self.create(state)
  File "/repo/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/update/update.py", line 77, in create
    runner.run()
  File "/repo/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/update/base.py", line 61, in run
    rv = step(self.logger).run(step_index, self.state)
  File "/repo/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/update/base.py", line 32, in run
    self.create(state)
  File "/repo/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/update/sync.py", line 111, in create
    update.update(state.sync["path"], state.test_manifest)
  File "/repo/tests/wpt/sync/tools/manifest/update.py", line 38, in update
    return manifest.update(tree, parallel)
  File "/repo/tests/wpt/sync/tools/manifest/manifest.py", line 249, in update
    for result in results:
  File "/usr/lib/python2.7/multiprocessing/pool.py", line 289, in <genexpr>
    return (item for chunk in result for item in chunk)
  File "/usr/lib/python2.7/multiprocessing/pool.py", line 673, in next
    raise value

I suspect web-platform-tests/wpt#23733.

[jdm]

<jgraham> jdm: Can you try setting parallel=False on the manifest update and see f you get a useful error message that way

IOError: [Errno 2] No such file or directory: u'/svg/historical.html'

  File "/Users/jdm/src/servo-tmp/python/servo/testing_commands.py", line 514, in update_wpt
    return run_globals["update_tests"](**kwargs)
  File "/Users/jdm/src/servo-tmp/tests/wpt/update.py", line 23, in update_tests
    rv = update.run_update(logger, **kwargs)
  File "/Users/jdm/src/servo-tmp/tests/wpt/update/__init__.py", line 26, in run_update
    return updater.run()
  File "/Users/jdm/src/servo-tmp/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/update/update.py", line 184, in run
    rv = update_runner.run()
  File "/Users/jdm/src/servo-tmp/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/update/base.py", line 61, in run
    rv = step(self.logger).run(step_index, self.state)
  File "/Users/jdm/src/servo-tmp/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/update/base.py", line 32, in run
    self.create(state)
  File "/Users/jdm/src/servo-tmp/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/update/update.py", line 77, in create
    runner.run()
  File "/Users/jdm/src/servo-tmp/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/update/base.py", line 61, in run
    rv = step(self.logger).run(step_index, self.state)
  File "/Users/jdm/src/servo-tmp/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/update/base.py", line 32, in run
    self.create(state)
  File "/Users/jdm/src/servo-tmp/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/update/sync.py", line 111, in create
    update.update(state.sync["path"], state.test_manifest, parallel=False)
  File "/Users/jdm/src/servo-tmp/tests/wpt/sync/tools/manifest/update.py", line 38, in update
    return manifest.update(tree, parallel)
  File "/Users/jdm/src/servo-tmp/tests/wpt/sync/tools/manifest/manifest.py", line 249, in update
    for result in results:
  File "/Users/jdm/src/servo-tmp/tests/wpt/sync/tools/manifest/manifest.py", line 83, in compute_manifest_items
    new_type, manifest_items = source_file.manifest_items()
  File "/Users/jdm/src/servo-tmp/tests/wpt/sync/tools/manifest/sourcefile.py", line 1017, in manifest_items
    elif self.content_is_css_manual and not self.name_is_reference:
  File "/Users/jdm/src/servo-tmp/tests/wpt/sync/tools/manifest/utils.py", line 91, in __get__
    rv = obj.__dict__[self.name] = self.func(obj)
  File "/Users/jdm/src/servo-tmp/tests/wpt/sync/tools/manifest/sourcefile.py", line 831, in content_is_css_manual
    if self.root is None:
  File "/Users/jdm/src/servo-tmp/tests/wpt/sync/tools/manifest/utils.py", line 91, in __get__
    rv = obj.__dict__[self.name] = self.func(obj)
  File "/Users/jdm/src/servo-tmp/tests/wpt/sync/tools/manifest/sourcefile.py", line 458, in root
    with self.open() as f:
  File "/Users/jdm/src/servo-tmp/tests/wpt/sync/tools/manifest/sourcefile.py", line 275, in open
    file_obj = open(self.path, 'rb')

[jdm]

@jgraham I'm finding it difficult to figure out what I can do next here, since this only seems to trigger when I do the sync from upstream, and the code that's causing problems is part of that upstream sync so I can't modify it to add helpful debugging prints.

[jdm]

Ok, I discovered that I can comment out most of https://github.com/web-platform-tests/wpt/blob/ce7bfaec86b1c6c926bdb0f2150e33a3a1bf1f54/tools/wptrunner/wptrunner/update/sync.py#L150-L155 and still reproduce it without overwriting my local changes. So the sourcefile in question has a tests_root of / and a rel_path of svg/historical.html. And the manifest has a tests_root of / and url_base of /.

[jgraham]

class LoadManifest(Step):
    """Load the test manifest"""

    provides = ["manifest_path", "test_manifest"]

    def create(self, state):
        from manifest import manifest
        state.manifest_path = os.path.join(state.metadata_path, "MANIFEST.json")
        state.test_manifest = manifest.Manifest("/")

in sync.py needs to be updated to pass in the tests_root as the first argument to the manifest.