view tests/test-verify-repo-operations.py @ 44950:f9734b2d59cc

py3: make stdout line-buffered if connected to a TTY Status messages that are to be shown on the terminal should be written to the file descriptor before anything further is done, to keep the user updated. One common way to achieve this is to make stdout line-buffered if it is connected to a TTY. This is done on Python 2 (except on Windows, where libc, which the CPython 2 streams depend on, does not properly support this). Python 3 rolls it own I/O streams. On Python 3, buffered binary streams can't be set line-buffered. The previous code (added in 227ba1afcb65) incorrectly assumed that on Python 3, pycompat.stdout (sys.stdout.buffer) is already line-buffered. However the interpreter initializes it with a block-buffered stream or an unbuffered stream (when the -u option or the PYTHONUNBUFFERED environment variable is set), never with a line-buffered stream. One example where the current behavior is unacceptable is when running `hg pull https://www.mercurial-scm.org/repo/hg` on Python 3, where the line "pulling from https://www.mercurial-scm.org/repo/hg" does not appear on the terminal before the hg process blocks while waiting for the server. Various approaches to fix this problem are possible, including: 1. Weaken the contract of procutil.stdout to not give any guarantees about buffering behavior. In this case, users of procutil.stdout need to be changed to do enough flushes. In particular, 1. either ui must insert enough flushes for ui.write() and friends, or 2. ui.write() and friends get split into flushing and fully buffered methods, or 3. users of ui.write() and friends must flush explicitly. 2. Make stdout unbuffered. 3. Make stdout line-buffered. Since Python 3 does not natively support that for binary streams, we must implement it ourselves. (2.) is problematic because using unbuffered I/O changes the performance characteristics significantly compared to line-buffered (which is used on Python 2) and this would be a regression. (1.2.) and (1.3) are a substantial amount of work. It’s unclear whether the added complexity would be justified, given that raw performance doesn’t matter that much when writing to a terminal much faster than the user could read it. (1.1.) pushes complexity into the ui class instead of separating the concern of how stdout is buffered. Other users of procutil.stdout would still need to take care of the flushes. This patch implements (3.). The general performance considerations are very similar to (1.1.). The extra method invocation and method forwarding add a little more overhead if the class is used. In exchange, it doesn’t add overhead if not used. For the benchmarks, I compared the previous implementation (incorrect on Python 3), (1.1.), (3.) and (2.). The command was chosen so that the streams were configured as if they were writing to a TTY, but actually write to a pager, which is also the default: HGRCPATH=/dev/null python3 ./hg --cwd ~/vcs/mozilla-central --time --pager yes --config pager.pager='cat > /dev/null' status --all previous: time: real 7.880 secs (user 7.290+0.050 sys 0.580+0.170) time: real 7.830 secs (user 7.220+0.070 sys 0.590+0.140) time: real 7.800 secs (user 7.210+0.050 sys 0.570+0.170) (1.1.) using Yuya Nishihara’s patch: time: real 9.860 secs (user 8.670+0.350 sys 1.160+0.830) time: real 9.540 secs (user 8.430+0.370 sys 1.100+0.770) time: real 9.830 secs (user 8.630+0.370 sys 1.180+0.840) (3.) using this patch: time: real 9.580 secs (user 8.480+0.350 sys 1.090+0.770) time: real 9.670 secs (user 8.480+0.330 sys 1.170+0.860) time: real 9.640 secs (user 8.500+0.350 sys 1.130+0.810) (2.) using a previous patch by me: time: real 10.480 secs (user 8.850+0.720 sys 1.590+1.500) time: real 10.490 secs (user 8.750+0.750 sys 1.710+1.470) time: real 10.240 secs (user 8.600+0.700 sys 1.590+1.510) As expected, there’s no difference on Python 2, as exactly the same code paths are used: previous: time: real 6.950 secs (user 5.870+0.330 sys 1.070+0.770) time: real 7.040 secs (user 6.040+0.360 sys 0.980+0.750) time: real 7.070 secs (user 5.950+0.360 sys 1.100+0.760) this patch: time: real 7.010 secs (user 5.900+0.390 sys 1.070+0.730) time: real 7.000 secs (user 5.850+0.350 sys 1.120+0.760) time: real 7.000 secs (user 5.790+0.380 sys 1.170+0.710)
author Manuel Jacob <me@manueljacob.de>
date Wed, 10 Jun 2020 13:02:39 +0200
parents 2372284d9457
children 89a2afe31e82
line wrap: on
line source

from __future__ import print_function, absolute_import

"""Fuzz testing for operations against a Mercurial repository

This uses Hypothesis's stateful testing to generate random repository
operations and test Mercurial using them, both to see if there are any
unexpected errors and to compare different versions of it."""

import os
import subprocess
import sys

# Only run if slow tests are allowed
if subprocess.call(['python', '%s/hghave' % os.environ['TESTDIR'], 'slow']):
    sys.exit(80)

# These tests require Hypothesis and pytz to be installed.
# Running 'pip install hypothesis pytz' will achieve that.
# Note: This won't work if you're running Python < 2.7.
try:
    from hypothesis.extra.datetime import datetimes
except ImportError:
    sys.stderr.write("skipped: hypothesis or pytz not installed" + os.linesep)
    sys.exit(80)

# If you are running an old version of pip you may find that the enum34
# backport is not installed automatically. If so 'pip install enum34' will
# fix this problem.
try:
    import enum

    assert enum  # Silence pyflakes
except ImportError:
    sys.stderr.write("skipped: enum34 not installed" + os.linesep)
    sys.exit(80)

import binascii
from contextlib import contextmanager
import errno
import pipes
import shutil
import silenttestrunner
import subprocess

from hypothesis.errors import HypothesisException
from hypothesis.stateful import (
    rule,
    RuleBasedStateMachine,
    Bundle,
    precondition,
)
from hypothesis import settings, note, strategies as st
from hypothesis.configuration import set_hypothesis_home_dir
from hypothesis.database import ExampleDatabase

testdir = os.path.abspath(os.environ["TESTDIR"])

# We store Hypothesis examples here rather in the temporary test directory
# so that when rerunning a failing test this always results in refinding the
# previous failure. This directory is in .hgignore and should not be checked in
# but is useful to have for development.
set_hypothesis_home_dir(os.path.join(testdir, ".hypothesis"))

runtests = os.path.join(os.environ["RUNTESTDIR"], "run-tests.py")
testtmp = os.environ["TESTTMP"]
assert os.path.isdir(testtmp)

generatedtests = os.path.join(testdir, "hypothesis-generated")

try:
    os.makedirs(generatedtests)
except OSError:
    pass

# We write out generated .t files to a file in order to ease debugging and to
# give a starting point for turning failures Hypothesis finds into normal
# tests. In order to ensure that multiple copies of this test can be run in
# parallel we use atomic file create to ensure that we always get a unique
# name.
file_index = 0
while True:
    file_index += 1
    savefile = os.path.join(
        generatedtests, "test-generated-%d.t" % (file_index,)
    )
    try:
        os.close(os.open(savefile, os.O_CREAT | os.O_EXCL | os.O_WRONLY))
        break
    except OSError as e:
        if e.errno != errno.EEXIST:
            raise
assert os.path.exists(savefile)

hgrc = os.path.join(".hg", "hgrc")

filecharacters = (
    "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
    "[]^_`;=@{}~ !#$%&'()+,-"
)

files = (
    st.text(filecharacters, min_size=1)
    .map(lambda x: x.strip())
    .filter(bool)
    .map(lambda s: s.encode('ascii'))
)

safetext = st.text(
    st.characters(
        min_codepoint=1, max_codepoint=127, blacklist_categories=('Cc', 'Cs')
    ),
    min_size=1,
).map(lambda s: s.encode('utf-8'))

extensions = st.sampled_from(('shelve', 'mq', 'blackbox',))


@contextmanager
def acceptableerrors(*args):
    """Sometimes we know an operation we're about to perform might fail, and
    we're OK with some of the failures. In those cases this may be used as a
    context manager and will swallow expected failures, as identified by
    substrings of the error message Mercurial emits."""
    try:
        yield
    except subprocess.CalledProcessError as e:
        if not any(a in e.output for a in args):
            note(e.output)
            raise


reponames = st.text("abcdefghijklmnopqrstuvwxyz01234556789", min_size=1).map(
    lambda s: s.encode('ascii')
)


class verifyingstatemachine(RuleBasedStateMachine):
    """This defines the set of acceptable operations on a Mercurial repository
    using Hypothesis's RuleBasedStateMachine.

    The general concept is that we manage multiple repositories inside a
    repos/ directory in our temporary test location. Some of these are freshly
    inited, some are clones of the others. Our current working directory is
    always inside one of these repositories while the tests are running.

    Hypothesis then performs a series of operations against these repositories,
    including hg commands, generating contents and editing the .hgrc file.
    If these operations fail in unexpected ways or behave differently in
    different configurations of Mercurial, the test will fail and a minimized
    .t test file will be written to the hypothesis-generated directory to
    exhibit that failure.

    Operations are defined as methods with @rule() decorators. See the
    Hypothesis documentation at
    http://hypothesis.readthedocs.org/en/release/stateful.html for more
    details."""

    # A bundle is a reusable collection of previously generated data which may
    # be provided as arguments to future operations.
    repos = Bundle('repos')
    paths = Bundle('paths')
    contents = Bundle('contents')
    branches = Bundle('branches')
    committimes = Bundle('committimes')

    def __init__(self):
        super(verifyingstatemachine, self).__init__()
        self.repodir = os.path.join(testtmp, "repos")
        if os.path.exists(self.repodir):
            shutil.rmtree(self.repodir)
        os.chdir(testtmp)
        self.log = []
        self.failed = False
        self.configperrepo = {}
        self.all_extensions = set()
        self.non_skippable_extensions = set()

        self.mkdirp("repos")
        self.cd("repos")
        self.mkdirp("repo1")
        self.cd("repo1")
        self.hg("init")

    def teardown(self):
        """On teardown we clean up after ourselves as usual, but we also
        do some additional testing: We generate a .t file based on our test
        run using run-test.py -i to get the correct output.

        We then test it in a number of other configurations, verifying that
        each passes the same test."""
        super(verifyingstatemachine, self).teardown()
        try:
            shutil.rmtree(self.repodir)
        except OSError:
            pass
        ttest = os.linesep.join("  " + l for l in self.log)
        os.chdir(testtmp)
        path = os.path.join(testtmp, "test-generated.t")
        with open(path, 'w') as o:
            o.write(ttest + os.linesep)
        with open(os.devnull, "w") as devnull:
            rewriter = subprocess.Popen(
                [runtests, "--local", "-i", path],
                stdin=subprocess.PIPE,
                stdout=devnull,
                stderr=devnull,
            )
            rewriter.communicate("yes")
            with open(path, 'r') as i:
                ttest = i.read()

        e = None
        if not self.failed:
            try:
                output = subprocess.check_output(
                    [runtests, path, "--local", "--pure"],
                    stderr=subprocess.STDOUT,
                )
                assert "Ran 1 test" in output, output
                for ext in self.all_extensions - self.non_skippable_extensions:
                    tf = os.path.join(
                        testtmp, "test-generated-no-%s.t" % (ext,)
                    )
                    with open(tf, 'w') as o:
                        for l in ttest.splitlines():
                            if l.startswith("  $ hg"):
                                l = l.replace(
                                    "--config %s=" % (extensionconfigkey(ext),),
                                    "",
                                )
                            o.write(l + os.linesep)
                    with open(tf, 'r') as r:
                        t = r.read()
                        assert ext not in t, t
                    output = subprocess.check_output(
                        [runtests, tf, "--local",], stderr=subprocess.STDOUT
                    )
                    assert "Ran 1 test" in output, output
            except subprocess.CalledProcessError as e:
                note(e.output)
        if self.failed or e is not None:
            with open(savefile, "wb") as o:
                o.write(ttest)
        if e is not None:
            raise e

    def execute_step(self, step):
        try:
            return super(verifyingstatemachine, self).execute_step(step)
        except (HypothesisException, KeyboardInterrupt):
            raise
        except Exception:
            self.failed = True
            raise

    # Section: Basic commands.
    def mkdirp(self, path):
        if os.path.exists(path):
            return
        self.log.append(
            "$ mkdir -p -- %s" % (pipes.quote(os.path.relpath(path)),)
        )
        os.makedirs(path)

    def cd(self, path):
        path = os.path.relpath(path)
        if path == ".":
            return
        os.chdir(path)
        self.log.append("$ cd -- %s" % (pipes.quote(path),))

    def hg(self, *args):
        extra_flags = []
        for key, value in self.config.items():
            extra_flags.append("--config")
            extra_flags.append("%s=%s" % (key, value))
        self.command("hg", *(tuple(extra_flags) + args))

    def command(self, *args):
        self.log.append("$ " + ' '.join(map(pipes.quote, args)))
        subprocess.check_output(args, stderr=subprocess.STDOUT)

    # Section: Set up basic data
    # This section has no side effects but generates data that we will want
    # to use later.
    @rule(
        target=paths,
        source=st.lists(files, min_size=1).map(lambda l: os.path.join(*l)),
    )
    def genpath(self, source):
        return source

    @rule(
        target=committimes,
        when=datetimes(min_year=1970, max_year=2038) | st.none(),
    )
    def gentime(self, when):
        return when

    @rule(
        target=contents,
        content=st.one_of(
            st.binary(), st.text().map(lambda x: x.encode('utf-8'))
        ),
    )
    def gencontent(self, content):
        return content

    @rule(
        target=branches, name=safetext,
    )
    def genbranch(self, name):
        return name

    @rule(target=paths, source=paths)
    def lowerpath(self, source):
        return source.lower()

    @rule(target=paths, source=paths)
    def upperpath(self, source):
        return source.upper()

    # Section: Basic path operations
    @rule(path=paths, content=contents)
    def writecontent(self, path, content):
        self.unadded_changes = True
        if os.path.isdir(path):
            return
        parent = os.path.dirname(path)
        if parent:
            try:
                self.mkdirp(parent)
            except OSError:
                # It may be the case that there is a regular file that has
                # previously been created that has the same name as an ancestor
                # of the current path. This will cause mkdirp to fail with this
                # error. We just turn this into a no-op in that case.
                return
        with open(path, 'wb') as o:
            o.write(content)
        self.log.append(
            (
                "$ python -c 'import binascii; "
                "print(binascii.unhexlify(\"%s\"))' > %s"
            )
            % (binascii.hexlify(content), pipes.quote(path),)
        )

    @rule(path=paths)
    def addpath(self, path):
        if os.path.exists(path):
            self.hg("add", "--", path)

    @rule(path=paths)
    def forgetpath(self, path):
        if os.path.exists(path):
            with acceptableerrors("file is already untracked",):
                self.hg("forget", "--", path)

    @rule(s=st.none() | st.integers(0, 100))
    def addremove(self, s):
        args = ["addremove"]
        if s is not None:
            args.extend(["-s", str(s)])
        self.hg(*args)

    @rule(path=paths)
    def removepath(self, path):
        if os.path.exists(path):
            with acceptableerrors(
                'file is untracked',
                'file has been marked for add',
                'file is modified',
            ):
                self.hg("remove", "--", path)

    @rule(
        message=safetext,
        amend=st.booleans(),
        when=committimes,
        addremove=st.booleans(),
        secret=st.booleans(),
        close_branch=st.booleans(),
    )
    def maybecommit(
        self, message, amend, when, addremove, secret, close_branch
    ):
        command = ["commit"]
        errors = ["nothing changed"]
        if amend:
            errors.append("cannot amend public changesets")
            command.append("--amend")
        command.append("-m" + pipes.quote(message))
        if secret:
            command.append("--secret")
        if close_branch:
            command.append("--close-branch")
            errors.append("can only close branch heads")
        if addremove:
            command.append("--addremove")
        if when is not None:
            if when.year == 1970:
                errors.append('negative date value')
            if when.year == 2038:
                errors.append('exceeds 32 bits')
            command.append(
                "--date=%s" % (when.strftime('%Y-%m-%d %H:%M:%S %z'),)
            )

        with acceptableerrors(*errors):
            self.hg(*command)

    # Section: Repository management
    @property
    def currentrepo(self):
        return os.path.basename(os.getcwd())

    @property
    def config(self):
        return self.configperrepo.setdefault(self.currentrepo, {})

    @rule(
        target=repos, source=repos, name=reponames,
    )
    def clone(self, source, name):
        if not os.path.exists(os.path.join("..", name)):
            self.cd("..")
            self.hg("clone", source, name)
            self.cd(name)
        return name

    @rule(
        target=repos, name=reponames,
    )
    def fresh(self, name):
        if not os.path.exists(os.path.join("..", name)):
            self.cd("..")
            self.mkdirp(name)
            self.cd(name)
            self.hg("init")
        return name

    @rule(name=repos)
    def switch(self, name):
        self.cd(os.path.join("..", name))
        assert self.currentrepo == name
        assert os.path.exists(".hg")

    @rule(target=repos)
    def origin(self):
        return "repo1"

    @rule()
    def pull(self, repo=repos):
        with acceptableerrors(
            "repository default not found", "repository is unrelated",
        ):
            self.hg("pull")

    @rule(newbranch=st.booleans())
    def push(self, newbranch):
        with acceptableerrors(
            "default repository not configured", "no changes found",
        ):
            if newbranch:
                self.hg("push", "--new-branch")
            else:
                with acceptableerrors("creates new branches"):
                    self.hg("push")

    # Section: Simple side effect free "check" operations
    @rule()
    def log(self):
        self.hg("log")

    @rule()
    def verify(self):
        self.hg("verify")

    @rule()
    def diff(self):
        self.hg("diff", "--nodates")

    @rule()
    def status(self):
        self.hg("status")

    @rule()
    def export(self):
        self.hg("export")

    # Section: Branch management
    @rule()
    def checkbranch(self):
        self.hg("branch")

    @rule(branch=branches)
    def switchbranch(self, branch):
        with acceptableerrors(
            'cannot use an integer as a name',
            'cannot be used in a name',
            'a branch of the same name already exists',
            'is reserved',
        ):
            self.hg("branch", "--", branch)

    @rule(branch=branches, clean=st.booleans())
    def update(self, branch, clean):
        with acceptableerrors(
            'unknown revision', 'parse error',
        ):
            if clean:
                self.hg("update", "-C", "--", branch)
            else:
                self.hg("update", "--", branch)

    # Section: Extension management
    def hasextension(self, extension):
        return extensionconfigkey(extension) in self.config

    def commandused(self, extension):
        assert extension in self.all_extensions
        self.non_skippable_extensions.add(extension)

    @rule(extension=extensions)
    def addextension(self, extension):
        self.all_extensions.add(extension)
        self.config[extensionconfigkey(extension)] = ""

    @rule(extension=extensions)
    def removeextension(self, extension):
        self.config.pop(extensionconfigkey(extension), None)

    # Section: Commands from the shelve extension
    @rule()
    @precondition(lambda self: self.hasextension("shelve"))
    def shelve(self):
        self.commandused("shelve")
        with acceptableerrors("nothing changed"):
            self.hg("shelve")

    @rule()
    @precondition(lambda self: self.hasextension("shelve"))
    def unshelve(self):
        self.commandused("shelve")
        with acceptableerrors("no shelved changes to apply"):
            self.hg("unshelve")


class writeonlydatabase(ExampleDatabase):
    def __init__(self, underlying):
        super(ExampleDatabase, self).__init__()
        self.underlying = underlying

    def fetch(self, key):
        return ()

    def save(self, key, value):
        self.underlying.save(key, value)

    def delete(self, key, value):
        self.underlying.delete(key, value)

    def close(self):
        self.underlying.close()


def extensionconfigkey(extension):
    return "extensions." + extension


settings.register_profile(
    'default', settings(timeout=300, stateful_step_count=50, max_examples=10,)
)

settings.register_profile(
    'fast',
    settings(
        timeout=10,
        stateful_step_count=20,
        max_examples=5,
        min_satisfying_examples=1,
        max_shrinks=0,
    ),
)

settings.register_profile(
    'continuous',
    settings(
        timeout=-1,
        stateful_step_count=1000,
        max_examples=10 ** 8,
        max_iterations=10 ** 8,
        database=writeonlydatabase(settings.default.database),
    ),
)

settings.load_profile(os.getenv('HYPOTHESIS_PROFILE', 'default'))

verifyingtest = verifyingstatemachine.TestCase

verifyingtest.settings = settings.default

if __name__ == '__main__':
    try:
        silenttestrunner.main(__name__)
    finally:
        # So as to prevent proliferation of useless test files, if we never
        # actually wrote a failing test we clean up after ourselves and delete
        # the file for doing so that we owned.
        if os.path.exists(savefile) and os.path.getsize(savefile) == 0:
            os.unlink(savefile)