view tests/test-wsgirequest.py @ 44118:f81c17ec303c

hgdemandimport: apply lazy module loading to sys.meta_path finders

Python's `sys.meta_path` finders are the primary objects whose job it
is to find a module at import time. When `import` is called, Python
iterates objects in this list and calls `o.find_spec(...)` to find
a `ModuleSpec` (or None if the module couldn't be found by that
finder). If no meta path finder can find a module, import fails.

One of the default meta path finders is `PathFinder`. Its job is to
import modules from the filesystem and is probably the most important
importer. This finder looks at `sys.path` and `sys.path_hooks` to do
its job.

The `ModuleSpec` returned by `MetaPathImporter.find_spec()` has a
`loader` attribute, which defines the concrete module loader to use.
`sys.path_hooks` is a hook point for teaching `PathFinder` to
instantiate custom loader types.

Previously, we injected a custom `sys.path_hook` that told `PathFinder`
to wrap the default loaders with a loader that creates a module object
that is lazy.

This approach worked. But its main limitation was that it only applied
to the `PathFinder` meta path importer. There are other meta path
importers that are registered. And in the case of PyOxidizer loading
modules from memory, `PathFinder` doesn't come into play since
PyOxidizer's own meta path importer was handling all imports.

This commit changes our approach to lazy module loading by proxying
all meta path importers. Specifically, we overload the `find_spec()`
method to swap in a wrapped loader on the `ModuleSpec` before it
is returned. The end result of this is all meta path importers should
be lazy.

As much as I would have loved to utilize .__class__ manipulation to
achieve this, some meta path importers are implemented in C/Rust
in such a way that they cannot be monkeypatched. This is why we
use __getattribute__ to define a proxy.

Also, this change could theoretically open us up to regressions in
meta path importers whose loader is creating module objects which
can't be monkeypatched. But I'm not aware of any of these in the
wild. So I think we'll be safe.

According to hyperfine, this change yields a decent startup time win of
5-6ms:

```
Benchmark #1: ~/.pyenv/versions/3.6.10/bin/python ./hg version
  Time (mean ± σ):      86.8 ms ±   0.5 ms    [User: 78.0 ms, System: 8.7 ms]
  Range (min … max):    86.0 ms …  89.1 ms    50 runs

  Time (mean ± σ):      81.1 ms ±   2.7 ms    [User: 74.5 ms, System: 6.5 ms]
  Range (min … max):    77.8 ms …  90.5 ms    50 runs

Benchmark #2: ~/.pyenv/versions/3.7.6/bin/python ./hg version
  Time (mean ± σ):      78.9 ms ±   0.6 ms    [User: 70.2 ms, System: 8.7 ms]
  Range (min … max):    78.1 ms …  81.2 ms    50 runs

  Time (mean ± σ):      73.4 ms ±   0.6 ms    [User: 65.3 ms, System: 8.0 ms]
  Range (min … max):    72.4 ms …  75.7 ms    50 runs

Benchmark #3: ~/.pyenv/versions/3.8.1/bin/python ./hg version
  Time (mean ± σ):      78.1 ms ±   0.6 ms    [User: 70.2 ms, System: 7.9 ms]
  Range (min … max):    77.4 ms …  80.9 ms    50 runs

  Time (mean ± σ):      72.1 ms ±   0.4 ms    [User: 64.4 ms, System: 7.6 ms]
  Range (min … max):    71.4 ms …  74.1 ms    50 runs
```

Differential Revision: https://phab.mercurial-scm.org/D7954

from __future__ import absolute_import, print_function

import unittest

from mercurial.hgweb import request as requestmod
from mercurial import error

DEFAULT_ENV = {
    'REQUEST_METHOD': 'GET',
    'SERVER_NAME': 'testserver',
    'SERVER_PORT': '80',
    'SERVER_PROTOCOL': 'http',
    'wsgi.version': (1, 0),
    'wsgi.url_scheme': 'http',
    'wsgi.input': None,
    'wsgi.errors': None,
    'wsgi.multithread': False,
    'wsgi.multiprocess': True,
    'wsgi.run_once': False,
}


def parse(env, reponame=None, altbaseurl=None, extra=None):
    env = dict(env)
    env.update(extra or {})

    return requestmod.parserequestfromenv(
        env, reponame=reponame, altbaseurl=altbaseurl
    )


class ParseRequestTests(unittest.TestCase):
    def testdefault(self):
        r = parse(DEFAULT_ENV)
        self.assertEqual(r.url, b'http://testserver')
        self.assertEqual(r.baseurl, b'http://testserver')
        self.assertEqual(r.advertisedurl, b'http://testserver')
        self.assertEqual(r.advertisedbaseurl, b'http://testserver')
        self.assertEqual(r.urlscheme, b'http')
        self.assertEqual(r.method, b'GET')
        self.assertIsNone(r.remoteuser)
        self.assertIsNone(r.remotehost)
        self.assertEqual(r.apppath, b'')
        self.assertEqual(r.dispatchparts, [])
        self.assertIsNone(r.dispatchpath)
        self.assertIsNone(r.reponame)
        self.assertEqual(r.querystring, b'')
        self.assertEqual(len(r.qsparams), 0)
        self.assertEqual(len(r.headers), 0)

    def testcustomport(self):
        r = parse(DEFAULT_ENV, extra={'SERVER_PORT': '8000',})

        self.assertEqual(r.url, b'http://testserver:8000')
        self.assertEqual(r.baseurl, b'http://testserver:8000')
        self.assertEqual(r.advertisedurl, b'http://testserver:8000')
        self.assertEqual(r.advertisedbaseurl, b'http://testserver:8000')

        r = parse(
            DEFAULT_ENV,
            extra={'SERVER_PORT': '4000', 'wsgi.url_scheme': 'https',},
        )

        self.assertEqual(r.url, b'https://testserver:4000')
        self.assertEqual(r.baseurl, b'https://testserver:4000')
        self.assertEqual(r.advertisedurl, b'https://testserver:4000')
        self.assertEqual(r.advertisedbaseurl, b'https://testserver:4000')

    def testhttphost(self):
        r = parse(DEFAULT_ENV, extra={'HTTP_HOST': 'altserver',})

        self.assertEqual(r.url, b'http://altserver')
        self.assertEqual(r.baseurl, b'http://altserver')
        self.assertEqual(r.advertisedurl, b'http://testserver')
        self.assertEqual(r.advertisedbaseurl, b'http://testserver')

    def testscriptname(self):
        r = parse(DEFAULT_ENV, extra={'SCRIPT_NAME': '',})

        self.assertEqual(r.url, b'http://testserver')
        self.assertEqual(r.baseurl, b'http://testserver')
        self.assertEqual(r.advertisedurl, b'http://testserver')
        self.assertEqual(r.advertisedbaseurl, b'http://testserver')
        self.assertEqual(r.apppath, b'')
        self.assertEqual(r.dispatchparts, [])
        self.assertIsNone(r.dispatchpath)

        r = parse(DEFAULT_ENV, extra={'SCRIPT_NAME': '/script',})

        self.assertEqual(r.url, b'http://testserver/script')
        self.assertEqual(r.baseurl, b'http://testserver')
        self.assertEqual(r.advertisedurl, b'http://testserver/script')
        self.assertEqual(r.advertisedbaseurl, b'http://testserver')
        self.assertEqual(r.apppath, b'/script')
        self.assertEqual(r.dispatchparts, [])
        self.assertIsNone(r.dispatchpath)

        r = parse(DEFAULT_ENV, extra={'SCRIPT_NAME': '/multiple words',})

        self.assertEqual(r.url, b'http://testserver/multiple%20words')
        self.assertEqual(r.baseurl, b'http://testserver')
        self.assertEqual(r.advertisedurl, b'http://testserver/multiple%20words')
        self.assertEqual(r.advertisedbaseurl, b'http://testserver')
        self.assertEqual(r.apppath, b'/multiple words')
        self.assertEqual(r.dispatchparts, [])
        self.assertIsNone(r.dispatchpath)

    def testpathinfo(self):
        r = parse(DEFAULT_ENV, extra={'PATH_INFO': '',})

        self.assertEqual(r.url, b'http://testserver')
        self.assertEqual(r.baseurl, b'http://testserver')
        self.assertEqual(r.advertisedurl, b'http://testserver')
        self.assertEqual(r.advertisedbaseurl, b'http://testserver')
        self.assertEqual(r.apppath, b'')
        self.assertEqual(r.dispatchparts, [])
        self.assertEqual(r.dispatchpath, b'')

        r = parse(DEFAULT_ENV, extra={'PATH_INFO': '/pathinfo',})

        self.assertEqual(r.url, b'http://testserver/pathinfo')
        self.assertEqual(r.baseurl, b'http://testserver')
        self.assertEqual(r.advertisedurl, b'http://testserver/pathinfo')
        self.assertEqual(r.advertisedbaseurl, b'http://testserver')
        self.assertEqual(r.apppath, b'')
        self.assertEqual(r.dispatchparts, [b'pathinfo'])
        self.assertEqual(r.dispatchpath, b'pathinfo')

        r = parse(DEFAULT_ENV, extra={'PATH_INFO': '/one/two/',})

        self.assertEqual(r.url, b'http://testserver/one/two/')
        self.assertEqual(r.baseurl, b'http://testserver')
        self.assertEqual(r.advertisedurl, b'http://testserver/one/two/')
        self.assertEqual(r.advertisedbaseurl, b'http://testserver')
        self.assertEqual(r.apppath, b'')
        self.assertEqual(r.dispatchparts, [b'one', b'two'])
        self.assertEqual(r.dispatchpath, b'one/two')

    def testscriptandpathinfo(self):
        r = parse(
            DEFAULT_ENV,
            extra={'SCRIPT_NAME': '/script', 'PATH_INFO': '/pathinfo',},
        )

        self.assertEqual(r.url, b'http://testserver/script/pathinfo')
        self.assertEqual(r.baseurl, b'http://testserver')
        self.assertEqual(r.advertisedurl, b'http://testserver/script/pathinfo')
        self.assertEqual(r.advertisedbaseurl, b'http://testserver')
        self.assertEqual(r.apppath, b'/script')
        self.assertEqual(r.dispatchparts, [b'pathinfo'])
        self.assertEqual(r.dispatchpath, b'pathinfo')

        r = parse(
            DEFAULT_ENV,
            extra={
                'SCRIPT_NAME': '/script1/script2',
                'PATH_INFO': '/path1/path2',
            },
        )

        self.assertEqual(
            r.url, b'http://testserver/script1/script2/path1/path2'
        )
        self.assertEqual(r.baseurl, b'http://testserver')
        self.assertEqual(
            r.advertisedurl, b'http://testserver/script1/script2/path1/path2'
        )
        self.assertEqual(r.advertisedbaseurl, b'http://testserver')
        self.assertEqual(r.apppath, b'/script1/script2')
        self.assertEqual(r.dispatchparts, [b'path1', b'path2'])
        self.assertEqual(r.dispatchpath, b'path1/path2')

        r = parse(
            DEFAULT_ENV,
            extra={
                'HTTP_HOST': 'hostserver',
                'SCRIPT_NAME': '/script',
                'PATH_INFO': '/pathinfo',
            },
        )

        self.assertEqual(r.url, b'http://hostserver/script/pathinfo')
        self.assertEqual(r.baseurl, b'http://hostserver')
        self.assertEqual(r.advertisedurl, b'http://testserver/script/pathinfo')
        self.assertEqual(r.advertisedbaseurl, b'http://testserver')
        self.assertEqual(r.apppath, b'/script')
        self.assertEqual(r.dispatchparts, [b'pathinfo'])
        self.assertEqual(r.dispatchpath, b'pathinfo')

    if not getattr(unittest.TestCase, 'assertRaisesRegex', False):
        # Python 3.7 deprecates the regex*p* version, but 2.7 lacks
        # the regex version.
        assertRaisesRegex = (  # camelcase-required
            unittest.TestCase.assertRaisesRegexp
        )

    def testreponame(self):
        """repository path components get stripped from URL."""

        with self.assertRaisesRegex(
            error.ProgrammingError, 'reponame requires PATH_INFO'
        ):
            parse(DEFAULT_ENV, reponame=b'repo')

        with self.assertRaisesRegex(
            error.ProgrammingError, 'PATH_INFO does not begin with repo ' 'name'
        ):
            parse(
                DEFAULT_ENV,
                reponame=b'repo',
                extra={'PATH_INFO': '/pathinfo',},
            )

        with self.assertRaisesRegex(
            error.ProgrammingError, 'reponame prefix of PATH_INFO'
        ):
            parse(
                DEFAULT_ENV,
                reponame=b'repo',
                extra={'PATH_INFO': '/repoextra/path',},
            )

        r = parse(
            DEFAULT_ENV,
            reponame=b'repo',
            extra={'PATH_INFO': '/repo/path1/path2',},
        )

        self.assertEqual(r.url, b'http://testserver/repo/path1/path2')
        self.assertEqual(r.baseurl, b'http://testserver')
        self.assertEqual(r.advertisedurl, b'http://testserver/repo/path1/path2')
        self.assertEqual(r.advertisedbaseurl, b'http://testserver')
        self.assertEqual(r.apppath, b'/repo')
        self.assertEqual(r.dispatchparts, [b'path1', b'path2'])
        self.assertEqual(r.dispatchpath, b'path1/path2')
        self.assertEqual(r.reponame, b'repo')

        r = parse(
            DEFAULT_ENV,
            reponame=b'prefix/repo',
            extra={'PATH_INFO': '/prefix/repo/path1/path2',},
        )

        self.assertEqual(r.url, b'http://testserver/prefix/repo/path1/path2')
        self.assertEqual(r.baseurl, b'http://testserver')
        self.assertEqual(
            r.advertisedurl, b'http://testserver/prefix/repo/path1/path2'
        )
        self.assertEqual(r.advertisedbaseurl, b'http://testserver')
        self.assertEqual(r.apppath, b'/prefix/repo')
        self.assertEqual(r.dispatchparts, [b'path1', b'path2'])
        self.assertEqual(r.dispatchpath, b'path1/path2')
        self.assertEqual(r.reponame, b'prefix/repo')

    def testaltbaseurl(self):
        # Simple hostname remap.
        r = parse(DEFAULT_ENV, altbaseurl=b'http://altserver')

        self.assertEqual(r.url, b'http://testserver')
        self.assertEqual(r.baseurl, b'http://testserver')
        self.assertEqual(r.advertisedurl, b'http://altserver')
        self.assertEqual(r.advertisedbaseurl, b'http://altserver')
        self.assertEqual(r.urlscheme, b'http')
        self.assertEqual(r.apppath, b'')
        self.assertEqual(r.dispatchparts, [])
        self.assertIsNone(r.dispatchpath)
        self.assertIsNone(r.reponame)

        # With a custom port.
        r = parse(DEFAULT_ENV, altbaseurl=b'http://altserver:8000')
        self.assertEqual(r.url, b'http://testserver')
        self.assertEqual(r.baseurl, b'http://testserver')
        self.assertEqual(r.advertisedurl, b'http://altserver:8000')
        self.assertEqual(r.advertisedbaseurl, b'http://altserver:8000')
        self.assertEqual(r.urlscheme, b'http')
        self.assertEqual(r.apppath, b'')
        self.assertEqual(r.dispatchparts, [])
        self.assertIsNone(r.dispatchpath)
        self.assertIsNone(r.reponame)

        # With a changed protocol.
        r = parse(DEFAULT_ENV, altbaseurl=b'https://altserver')
        self.assertEqual(r.url, b'http://testserver')
        self.assertEqual(r.baseurl, b'http://testserver')
        self.assertEqual(r.advertisedurl, b'https://altserver')
        self.assertEqual(r.advertisedbaseurl, b'https://altserver')
        # URL scheme is defined as the actual scheme, not advertised.
        self.assertEqual(r.urlscheme, b'http')
        self.assertEqual(r.apppath, b'')
        self.assertEqual(r.dispatchparts, [])
        self.assertIsNone(r.dispatchpath)
        self.assertIsNone(r.reponame)

        # Need to specify explicit port number for proper https:// alt URLs.
        r = parse(DEFAULT_ENV, altbaseurl=b'https://altserver:443')
        self.assertEqual(r.url, b'http://testserver')
        self.assertEqual(r.baseurl, b'http://testserver')
        self.assertEqual(r.advertisedurl, b'https://altserver')
        self.assertEqual(r.advertisedbaseurl, b'https://altserver')
        self.assertEqual(r.urlscheme, b'http')
        self.assertEqual(r.apppath, b'')
        self.assertEqual(r.dispatchparts, [])
        self.assertIsNone(r.dispatchpath)
        self.assertIsNone(r.reponame)

        # With only PATH_INFO defined.
        r = parse(
            DEFAULT_ENV,
            altbaseurl=b'http://altserver',
            extra={'PATH_INFO': '/path1/path2',},
        )
        self.assertEqual(r.url, b'http://testserver/path1/path2')
        self.assertEqual(r.baseurl, b'http://testserver')
        self.assertEqual(r.advertisedurl, b'http://altserver/path1/path2')
        self.assertEqual(r.advertisedbaseurl, b'http://altserver')
        self.assertEqual(r.urlscheme, b'http')
        self.assertEqual(r.apppath, b'')
        self.assertEqual(r.dispatchparts, [b'path1', b'path2'])
        self.assertEqual(r.dispatchpath, b'path1/path2')
        self.assertIsNone(r.reponame)

        # Path on alt URL.
        r = parse(DEFAULT_ENV, altbaseurl=b'http://altserver/altpath')
        self.assertEqual(r.url, b'http://testserver')
        self.assertEqual(r.baseurl, b'http://testserver')
        self.assertEqual(r.advertisedurl, b'http://altserver/altpath')
        self.assertEqual(r.advertisedbaseurl, b'http://altserver')
        self.assertEqual(r.urlscheme, b'http')
        self.assertEqual(r.apppath, b'/altpath')
        self.assertEqual(r.dispatchparts, [])
        self.assertIsNone(r.dispatchpath)
        self.assertIsNone(r.reponame)

        # With a trailing slash.
        r = parse(DEFAULT_ENV, altbaseurl=b'http://altserver/altpath/')
        self.assertEqual(r.url, b'http://testserver')
        self.assertEqual(r.baseurl, b'http://testserver')
        self.assertEqual(r.advertisedurl, b'http://altserver/altpath/')
        self.assertEqual(r.advertisedbaseurl, b'http://altserver')
        self.assertEqual(r.urlscheme, b'http')
        self.assertEqual(r.apppath, b'/altpath/')
        self.assertEqual(r.dispatchparts, [])
        self.assertIsNone(r.dispatchpath)
        self.assertIsNone(r.reponame)

        # PATH_INFO + path on alt URL.
        r = parse(
            DEFAULT_ENV,
            altbaseurl=b'http://altserver/altpath',
            extra={'PATH_INFO': '/path1/path2',},
        )
        self.assertEqual(r.url, b'http://testserver/path1/path2')
        self.assertEqual(r.baseurl, b'http://testserver')
        self.assertEqual(
            r.advertisedurl, b'http://altserver/altpath/path1/path2'
        )
        self.assertEqual(r.advertisedbaseurl, b'http://altserver')
        self.assertEqual(r.urlscheme, b'http')
        self.assertEqual(r.apppath, b'/altpath')
        self.assertEqual(r.dispatchparts, [b'path1', b'path2'])
        self.assertEqual(r.dispatchpath, b'path1/path2')
        self.assertIsNone(r.reponame)

        # PATH_INFO + path on alt URL with trailing slash.
        r = parse(
            DEFAULT_ENV,
            altbaseurl=b'http://altserver/altpath/',
            extra={'PATH_INFO': '/path1/path2',},
        )
        self.assertEqual(r.url, b'http://testserver/path1/path2')
        self.assertEqual(r.baseurl, b'http://testserver')
        self.assertEqual(
            r.advertisedurl, b'http://altserver/altpath//path1/path2'
        )
        self.assertEqual(r.advertisedbaseurl, b'http://altserver')
        self.assertEqual(r.urlscheme, b'http')
        self.assertEqual(r.apppath, b'/altpath/')
        self.assertEqual(r.dispatchparts, [b'path1', b'path2'])
        self.assertEqual(r.dispatchpath, b'path1/path2')
        self.assertIsNone(r.reponame)

        # Local SCRIPT_NAME is ignored.
        r = parse(
            DEFAULT_ENV,
            altbaseurl=b'http://altserver',
            extra={'SCRIPT_NAME': '/script', 'PATH_INFO': '/path1/path2',},
        )
        self.assertEqual(r.url, b'http://testserver/script/path1/path2')
        self.assertEqual(r.baseurl, b'http://testserver')
        self.assertEqual(r.advertisedurl, b'http://altserver/path1/path2')
        self.assertEqual(r.advertisedbaseurl, b'http://altserver')
        self.assertEqual(r.urlscheme, b'http')
        self.assertEqual(r.apppath, b'')
        self.assertEqual(r.dispatchparts, [b'path1', b'path2'])
        self.assertEqual(r.dispatchpath, b'path1/path2')
        self.assertIsNone(r.reponame)

        # Use remote's path for script name, app path
        r = parse(
            DEFAULT_ENV,
            altbaseurl=b'http://altserver/altroot',
            extra={'SCRIPT_NAME': '/script', 'PATH_INFO': '/path1/path2',},
        )
        self.assertEqual(r.url, b'http://testserver/script/path1/path2')
        self.assertEqual(r.baseurl, b'http://testserver')
        self.assertEqual(
            r.advertisedurl, b'http://altserver/altroot/path1/path2'
        )
        self.assertEqual(r.advertisedbaseurl, b'http://altserver')
        self.assertEqual(r.urlscheme, b'http')
        self.assertEqual(r.apppath, b'/altroot')
        self.assertEqual(r.dispatchparts, [b'path1', b'path2'])
        self.assertEqual(r.dispatchpath, b'path1/path2')
        self.assertIsNone(r.reponame)

        # reponame is factored in properly.
        r = parse(
            DEFAULT_ENV,
            reponame=b'repo',
            altbaseurl=b'http://altserver/altroot',
            extra={'SCRIPT_NAME': '/script', 'PATH_INFO': '/repo/path1/path2',},
        )

        self.assertEqual(r.url, b'http://testserver/script/repo/path1/path2')
        self.assertEqual(r.baseurl, b'http://testserver')
        self.assertEqual(
            r.advertisedurl, b'http://altserver/altroot/repo/path1/path2'
        )
        self.assertEqual(r.advertisedbaseurl, b'http://altserver')
        self.assertEqual(r.apppath, b'/altroot/repo')
        self.assertEqual(r.dispatchparts, [b'path1', b'path2'])
        self.assertEqual(r.dispatchpath, b'path1/path2')
        self.assertEqual(r.reponame, b'repo')


if __name__ == '__main__':
    import silenttestrunner

    silenttestrunner.main(__name__)