DXR is a code search and navigation tool aimed at making sense of large projects. It supports full-text and regex searches as well as structural queries.

Mercurial (a41a482b7876)

VCS Links

Line Code
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

"""Robustly perform a checkout.

This extension provides the ``hg robustcheckout`` command for
ensuring a working directory is updated to the specified revision
from a source repo using best practices to ensure optimal clone
times and storage efficiency.
"""

from __future__ import absolute_import

import contextlib
import errno
import functools
import os
import random
import re
import socket
import time
import urllib2

from mercurial.i18n import _
from mercurial.node import hex
from mercurial import (
    commands,
    error,
    exchange,
    extensions,
    cmdutil,
    hg,
    scmutil,
    util,
)

testedwith = '3.7 3.8 3.9 4.0 4.1'
minimumhgversion = '3.7'

cmdtable = {}
command = cmdutil.command(cmdtable)


if os.name == 'nt':
    import ctypes

    # Get a reference to the DeleteFileW function
    # DeleteFileW accepts filenames encoded as a null terminated sequence of
    # wide chars (UTF-16). Python's ctypes.c_wchar_p correctly encodes unicode
    # strings to null terminated UTF-16 strings.
    # However, we receive (byte) strings from mercurial. When these are passed
    # to DeleteFileW via the c_wchar_p type, they are implicitly decoded via
    # the 'mbcs' encoding on windows.
    kernel32 = ctypes.windll.kernel32
    DeleteFile = kernel32.DeleteFileW
    DeleteFile.argtypes = [ctypes.c_wchar_p]
    DeleteFile.restype = ctypes.c_bool

    def unlinklong(fn):
        normalized_path = '\\\\?\\' + os.path.normpath(fn)
        if not DeleteFile(normalized_path):
            raise OSError(errno.EPERM, "couldn't remove long path", fn)

# Not needed on other platforms, but is handy for testing
else:
    def unlinklong(fn):
        os.unlink(fn)


def unlinkwrapper(unlinkorig, fn, ui):
    '''Calls unlink_long if original unlink function fails.'''
    try:
        ui.debug('calling unlink_orig %s\n' % fn)
        return unlinkorig(fn)
    except WindowsError as e:
        # Windows error 3 corresponds to ERROR_PATH_NOT_FOUND
        # only handle this case; re-raise the exception for other kinds of
        # failures.
        if e.winerror != 3:
            raise
        ui.debug('caught WindowsError ERROR_PATH_NOT_FOUND; '
                 'calling unlink_long %s\n' % fn)
        return unlinklong(fn)


@contextlib.contextmanager
def wrapunlink(ui):
    '''Context manager that temporarily monkeypatches unlink functions.'''
    purgemod = extensions.find('purge')
    to_wrap = [(purgemod.util, 'unlink')]

    # Pass along the ui object to the unlink_wrapper so we can get logging out
    # of it.
    wrapped = functools.partial(unlinkwrapper, ui=ui)

    # Wrap the original function(s) with our unlink wrapper.
    originals = {}
    for mod, func in to_wrap:
        ui.debug('wrapping %s %s\n' % (mod, func))
        originals[mod, func] = extensions.wrapfunction(mod, func, wrapped)

    try:
        yield
    finally:
        # Restore the originals.
        for mod, func in to_wrap:
            ui.debug('restoring %s %s\n' % (mod, func))
            setattr(mod, func, originals[mod, func])


def purgewrapper(orig, ui, *args, **kwargs):
    '''Runs original purge() command with unlink monkeypatched.'''
    with wrapunlink(ui):
        return orig(ui, *args, **kwargs)


@command('robustcheckout', [
    ('', 'upstream', '', 'URL of upstream repo to clone from'),
    ('r', 'revision', '', 'Revision to check out'),
    ('b', 'branch', '', 'Branch to check out'),
    ('', 'purge', False, 'Whether to purge the working directory'),
    ('', 'sharebase', '', 'Directory where shared repos should be placed'),
    ('', 'networkattempts', 3, 'Maximum number of attempts for network '
                               'operations'),
    ],
    '[OPTION]... URL DEST',
    norepo=True)
def robustcheckout(ui, url, dest, upstream=None, revision=None, branch=None,
                   purge=False, sharebase=None, networkattempts=None):
    """Ensure a working copy has the specified revision checked out."""
    if not revision and not branch:
        raise error.Abort('must specify one of --revision or --branch')

    if revision and branch:
        raise error.Abort('cannot specify both --revision and --branch')

    # Require revision to look like a SHA-1.
    if revision:
        if len(revision) < 12 or len(revision) > 40 or not re.match('^[a-f0-9]+$', revision):
            raise error.Abort('--revision must be a SHA-1 fragment 12-40 '
                              'characters long')

    sharebase = sharebase or ui.config('share', 'pool')
    if not sharebase:
        raise error.Abort('share base directory not defined; refusing to operate',
                          hint='define share.pool config option or pass --sharebase')

    # worker.backgroundclose only makes things faster if running anti-virus,
    # which our automation doesn't. Disable it.
    ui.setconfig('worker', 'backgroundclose', False)

    # By default the progress bar starts after 3s and updates every 0.1s. We
    # change this so it shows and updates every 1.0s.
    # We also tell progress to assume a TTY is present so updates are printed
    # even if there is no known TTY.
    # We make the config change here instead of in a config file because
    # otherwise we're at the whim of whatever configs are used in automation.
    ui.setconfig('progress', 'delay', 1.0)
    ui.setconfig('progress', 'refresh', 1.0)
    ui.setconfig('progress', 'assume-tty', True)

    sharebase = os.path.realpath(sharebase)

    return _docheckout(ui, url, dest, upstream, revision, branch, purge,
                       sharebase, networkattempts)

def _docheckout(ui, url, dest, upstream, revision, branch, purge, sharebase,
                networkattemptlimit, networkattempts=None):
    if not networkattempts:
        networkattempts = [1]

    def callself():
        return _docheckout(ui, url, dest, upstream, revision, branch, purge,
                           sharebase, networkattemptlimit, networkattempts)

    ui.write('ensuring %s@%s is available at %s\n' % (url, revision or branch,
                                                      dest))

    destvfs = scmutil.vfs(dest, audit=False, realpath=True)

    if destvfs.exists() and not destvfs.exists('.hg'):
        raise error.Abort('destination exists but no .hg directory')

    # Require checkouts to be tied to shared storage because efficiency.
    if destvfs.exists('.hg') and not destvfs.exists('.hg/sharedpath'):
        ui.warn('(destination is not shared; deleting)\n')
        destvfs.rmtree(forcibly=True)

    # Verify the shared path exists and is using modern pooled storage.
    if destvfs.exists('.hg/sharedpath'):
        storepath = destvfs.read('.hg/sharedpath').strip()

        ui.write('(existing repository shared store: %s)\n' % storepath)

        if not os.path.exists(storepath):
            ui.warn('(shared store does not exist; deleting)\n')
            destvfs.rmtree(forcibly=True)
        elif not re.search('[a-f0-9]{40}/\.hg$', storepath.replace('\\', '/')):
            ui.warn('(shared store does not belong to pooled storage; '
                    'deleting to improve efficiency)\n')
            destvfs.rmtree(forcibly=True)

        # FUTURE when we require generaldelta, this is where we can check
        # for that.

    def deletesharedstore():
        storepath = destvfs.read('.hg/sharedpath').strip()
        if storepath.endswith('.hg'):
            storepath = os.path.dirname(storepath)

        storevfs = scmutil.vfs(storepath, audit=False)
        storevfs.rmtree(forcibly=True)

    def handlerepoerror(e):
        if e.message == _('abandoned transaction found'):
            ui.warn('(abandoned transaction found; trying to recover)\n')
            repo = hg.repository(ui, dest)
            if not repo.recover():
                ui.warn('(could not recover repo state; '
                        'deleting shared store)\n')
                deletesharedstore()

            ui.warn('(attempting checkout from beginning)\n')
            return callself()

        raise

    # At this point we either have an existing working directory using
    # shared, pooled storage or we have nothing.

    def handlenetworkfailure():
        if networkattempts[0] >= networkattemptlimit:
            raise error.Abort('reached maximum number of network attempts; '
                              'giving up\n')

        ui.warn('(retrying after network failure on attempt %d of %d)\n' %
                (networkattempts[0], networkattemptlimit))

        # Do a backoff on retries to mitigate the thundering herd
        # problem. This is an exponential backoff with a multipler
        # plus random jitter thrown in for good measure.
        # With the default settings, backoffs will be:
        # 1) 2.5 - 6.5
        # 2) 5.5 - 9.5
        # 3) 11.5 - 15.5
        backoff = (2 ** networkattempts[0] - 1) * 1.5
        jittermin = ui.configint('robustcheckout', 'retryjittermin', 1000)
        jittermax = ui.configint('robustcheckout', 'retryjittermax', 5000)
        backoff += float(random.randint(jittermin, jittermax)) / 1000.0
        ui.warn('(waiting %.2fs before retry)\n' % backoff)
        time.sleep(backoff)

        networkattempts[0] += 1

    def handlepullerror(e):
        """Handle an exception raised during a pull.

        Returns True if caller should call ``callself()`` to retry.
        """
        if isinstance(e, error.Abort):
            if e.args[0] == _('repository is unrelated'):
                ui.warn('(repository is unrelated; deleting)\n')
                destvfs.rmtree(forcibly=True)
                return True
            elif e.args[0].startswith(_('stream ended unexpectedly')):
                ui.warn('%s\n' % e.args[0])
                # Will raise if failure limit reached.
                handlenetworkfailure()
                return True
        elif isinstance(e, urllib2.URLError):
            if isinstance(e.reason, socket.error):
                ui.warn('socket error: %s\n' % e.reason)
                handlenetworkfailure()
                return True

        return False

    created = False

    if not destvfs.exists():
        # Ensure parent directories of destination exist.
        # Mercurial 3.8 removed ensuredirs and made makedirs race safe.
        if util.safehasattr(util, 'ensuredirs'):
            makedirs = util.ensuredirs
        else:
            makedirs = util.makedirs

        makedirs(os.path.dirname(destvfs.base), notindexed=True)
        makedirs(sharebase, notindexed=True)

        if upstream:
            ui.write('(cloning from upstream repo %s)\n' % upstream)
        cloneurl = upstream or url

        try:
            res = hg.clone(ui, {}, cloneurl, dest=dest, update=False,
                           shareopts={'pool': sharebase, 'mode': 'identity'})
        except (error.Abort, urllib2.URLError) as e:
            if handlepullerror(e):
                return callself()
            raise
        except error.RepoError as e:
            return handlerepoerror(e)
        except error.RevlogError as e:
            ui.warn('(repo corruption: %s; deleting shared store)\n' % e.message)
            deletesharedstore()
            return callself()

        # TODO retry here.
        if res is None:
            raise error.Abort('clone failed')

        # Verify it is using shared pool storage.
        if not destvfs.exists('.hg/sharedpath'):
            raise error.Abort('clone did not create a shared repo')

        created = True

    # The destination .hg directory should exist. Now make sure we have the
    # wanted revision.

    repo = hg.repository(ui, dest)

    # We only pull if we are using symbolic names or the requested revision
    # doesn't exist.
    havewantedrev = False
    if revision and revision in repo:
        ctx = repo[revision]

        if not ctx.hex().startswith(revision):
            raise error.Abort('--revision argument is ambiguous',
                              hint='must be the first 12+ characters of a '
                                   'SHA-1 fragment')

        checkoutrevision = ctx.hex()
        havewantedrev = True

    if not havewantedrev:
        ui.write('(pulling to obtain %s)\n' % (revision or branch,))

        remote = None
        try:
            remote = hg.peer(repo, {}, url)
            pullrevs = [remote.lookup(revision or branch)]
            checkoutrevision = hex(pullrevs[0])
            if branch:
                ui.warn('(remote resolved %s to %s; '
                        'result is not deterministic)\n' %
                        (branch, checkoutrevision))

            if checkoutrevision in repo:
                ui.warn('(revision already present locally; not pulling)\n')
            else:
                pullop = exchange.pull(repo, remote, heads=pullrevs)
                if not pullop.rheads:
                    raise error.Abort('unable to pull requested revision')
        except (error.Abort, urllib2.URLError) as e:
            if handlepullerror(e):
                return callself()
            raise
        except error.RepoError as e:
            return handlerepoerror(e)
        except error.RevlogError as e:
            ui.warn('(repo corruption: %s; deleting shared store)\n' % e.message)
            deletesharedstore()
            return callself()
        finally:
            if remote:
                remote.close()

    # Now we should have the wanted revision in the store. Perform
    # working directory manipulation.

    # Purge if requested. We purge before update because this way we're
    # guaranteed to not have conflicts on `hg update`.
    if purge and not created:
        ui.write('(purging working directory)\n')
        purgeext = extensions.find('purge')

        if purgeext.purge(ui, repo, all=True, abort_on_err=True,
                          # The function expects all arguments to be
                          # defined.
                          **{'print': None, 'print0': None, 'dirs': None,
                             'files': None}):
            raise error.Abort('error purging')

    # Update the working directory.
    if commands.update(ui, repo, rev=checkoutrevision, clean=True):
        raise error.Abort('error updating')

    ui.write('updated to %s\n' % checkoutrevision)
    return None


def extsetup(ui):
    # Ensure required extensions are loaded.
    for ext in ('purge', 'share'):
        try:
            extensions.find(ext)
        except KeyError:
            extensions.load(ui, ext, None)

    purgemod = extensions.find('purge')
    extensions.wrapcommand(purgemod.cmdtable, 'purge', purgewrapper)