view mercurial/verify.py @ 45390:7d24201b6447

worker: don't expose readinto() on _blockingreader since pickle is picky

The `pickle` module expects the input to be buffered and a whole
object to be available when `pickle.load()` is called, which is not
necessarily true when we send data from workers back to the parent
process (i.e., it seems like a bad assumption for the `pickle` module
to make). We added a workaround for that in
https://phab.mercurial-scm.org/D8076, which made `read()` continue
until all the requested bytes have been read.

As we found out at work after a lot of investigation (I've spent the
last two days on this), the native version of `pickle.load()` has
started calling `readinto()` on the input since Python 3.8. That
started being called in
https://github.com/python/cpython/commit/91f4380cedbae32b49adbea2518014a5624c6523
(and only by the C version of `pickle.load()`)). Before that, it was
only `read()` and `readline()` that were called. The problem with that
was that `readinto()` on our `_blockingreader` was simply delegating
to the underlying, *unbuffered* object. The symptom we saw was that
`hg fix` started failing sometimes on Python 3.8 on Mac. It failed
very relyable in some cases. I still haven't figured out under what
circumstances it fails and I've been unable to reproduce it in test
cases (I've tried writing larger amounts of data, using different
numbers of workers, and making the formatters sleep). I have, however,
been able to reproduce it 3-4 times on Linux, but then it stopped
reproducing on the following few hundred attempts.

To fix the problem, we can simply remove the implementation of
`readinto()`, since the unpickler will then fall back to calling
`read()`. The fallback was added a bit later, in
https://github.com/python/cpython/commit/b19f7ecfa3adc6ba1544225317b9473649815b38. However,
that commit also added checking that what `read()` returns is a
`bytes`, so we also need to convert the `bytearray` we use into
that. I was able to add a test for that failure at least.

Differential Revision: https://phab.mercurial-scm.org/D8928

# verify.py - repository integrity checking for Mercurial
#
# Copyright 2006, 2007 Matt Mackall <[e-mail]>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

from __future__ import absolute_import

import os

from .i18n import _
from .node import (
    nullid,
    short,
)

from . import (
    error,
    pycompat,
    revlog,
    util,
)

VERIFY_DEFAULT = 0
VERIFY_FULL = 1


def verify(repo, level=None):
    with repo.lock():
        v = verifier(repo, level)
        return v.verify()


def _normpath(f):
    # under hg < 2.4, convert didn't sanitize paths properly, so a
    # converted repo may contain repeated slashes
    while b'//' in f:
        f = f.replace(b'//', b'/')
    return f


class verifier(object):
    def __init__(self, repo, level=None):
        self.repo = repo.unfiltered()
        self.ui = repo.ui
        self.match = repo.narrowmatch()
        if level is None:
            level = VERIFY_DEFAULT
        self._level = level
        self.badrevs = set()
        self.errors = 0
        self.warnings = 0
        self.havecl = len(repo.changelog) > 0
        self.havemf = len(repo.manifestlog.getstorage(b'')) > 0
        self.revlogv1 = repo.changelog.version != revlog.REVLOGV0
        self.lrugetctx = util.lrucachefunc(repo.unfiltered().__getitem__)
        self.refersmf = False
        self.fncachewarned = False
        # developer config: verify.skipflags
        self.skipflags = repo.ui.configint(b'verify', b'skipflags')
        self.warnorphanstorefiles = True

    def _warn(self, msg):
        """record a "warning" level issue"""
        self.ui.warn(msg + b"\n")
        self.warnings += 1

    def _err(self, linkrev, msg, filename=None):
        """record a "error" level issue"""
        if linkrev is not None:
            self.badrevs.add(linkrev)
            linkrev = b"%d" % linkrev
        else:
            linkrev = b'?'
        msg = b"%s: %s" % (linkrev, msg)
        if filename:
            msg = b"%s@%s" % (filename, msg)
        self.ui.warn(b" " + msg + b"\n")
        self.errors += 1

    def _exc(self, linkrev, msg, inst, filename=None):
        """record exception raised during the verify process"""
        fmsg = pycompat.bytestr(inst)
        if not fmsg:
            fmsg = pycompat.byterepr(inst)
        self._err(linkrev, b"%s: %s" % (msg, fmsg), filename)

    def _checkrevlog(self, obj, name, linkrev):
        """verify high level property of a revlog

        - revlog is present,
        - revlog is non-empty,
        - sizes (index and data) are correct,
        - revlog's format version is correct.
        """
        if not len(obj) and (self.havecl or self.havemf):
            self._err(linkrev, _(b"empty or missing %s") % name)
            return

        d = obj.checksize()
        if d[0]:
            self._err(None, _(b"data length off by %d bytes") % d[0], name)
        if d[1]:
            self._err(None, _(b"index contains %d extra bytes") % d[1], name)

        if obj.version != revlog.REVLOGV0:
            if not self.revlogv1:
                self._warn(_(b"warning: `%s' uses revlog format 1") % name)
        elif self.revlogv1:
            self._warn(_(b"warning: `%s' uses revlog format 0") % name)

    def _checkentry(self, obj, i, node, seen, linkrevs, f):
        """verify a single revlog entry

        arguments are:
        - obj:      the source revlog
        - i:        the revision number
        - node:        the revision node id
        - seen:     nodes previously seen for this revlog
        - linkrevs: [changelog-revisions] introducing "node"
        - f:        string label ("changelog", "manifest", or filename)

        Performs the following checks:
        - linkrev points to an existing changelog revision,
        - linkrev points to a changelog revision that introduces this revision,
        - linkrev points to the lowest of these changesets,
        - both parents exist in the revlog,
        - the revision is not duplicated.

        Return the linkrev of the revision (or None for changelog's revisions).
        """
        lr = obj.linkrev(obj.rev(node))
        if lr < 0 or (self.havecl and lr not in linkrevs):
            if lr < 0 or lr >= len(self.repo.changelog):
                msg = _(b"rev %d points to nonexistent changeset %d")
            else:
                msg = _(b"rev %d points to unexpected changeset %d")
            self._err(None, msg % (i, lr), f)
            if linkrevs:
                if f and len(linkrevs) > 1:
                    try:
                        # attempt to filter down to real linkrevs
                        linkrevs = [
                            l
                            for l in linkrevs
                            if self.lrugetctx(l)[f].filenode() == node
                        ]
                    except Exception:
                        pass
                self._warn(
                    _(b" (expected %s)")
                    % b" ".join(map(pycompat.bytestr, linkrevs))
                )
            lr = None  # can't be trusted

        try:
            p1, p2 = obj.parents(node)
            if p1 not in seen and p1 != nullid:
                self._err(
                    lr,
                    _(b"unknown parent 1 %s of %s") % (short(p1), short(node)),
                    f,
                )
            if p2 not in seen and p2 != nullid:
                self._err(
                    lr,
                    _(b"unknown parent 2 %s of %s") % (short(p2), short(node)),
                    f,
                )
        except Exception as inst:
            self._exc(lr, _(b"checking parents of %s") % short(node), inst, f)

        if node in seen:
            self._err(lr, _(b"duplicate revision %d (%d)") % (i, seen[node]), f)
        seen[node] = i
        return lr

    def verify(self):
        """verify the content of the Mercurial repository

        This method run all verifications, displaying issues as they are found.

        return 1 if any error have been encountered, 0 otherwise."""
        # initial validation and generic report
        repo = self.repo
        ui = repo.ui
        if not repo.url().startswith(b'file:'):
            raise error.Abort(_(b"cannot verify bundle or remote repos"))

        if os.path.exists(repo.sjoin(b"journal")):
            ui.warn(_(b"abandoned transaction found - run hg recover\n"))

        if ui.verbose or not self.revlogv1:
            ui.status(
                _(b"repository uses revlog format %d\n")
                % (self.revlogv1 and 1 or 0)
            )

        # data verification
        mflinkrevs, filelinkrevs = self._verifychangelog()
        filenodes = self._verifymanifest(mflinkrevs)
        del mflinkrevs
        self._crosscheckfiles(filelinkrevs, filenodes)
        totalfiles, filerevisions = self._verifyfiles(filenodes, filelinkrevs)

        # final report
        ui.status(
            _(b"checked %d changesets with %d changes to %d files\n")
            % (len(repo.changelog), filerevisions, totalfiles)
        )
        if self.warnings:
            ui.warn(_(b"%d warnings encountered!\n") % self.warnings)
        if self.fncachewarned:
            ui.warn(
                _(
                    b'hint: run "hg debugrebuildfncache" to recover from '
                    b'corrupt fncache\n'
                )
            )
        if self.errors:
            ui.warn(_(b"%d integrity errors encountered!\n") % self.errors)
            if self.badrevs:
                ui.warn(
                    _(b"(first damaged changeset appears to be %d)\n")
                    % min(self.badrevs)
                )
            return 1
        return 0

    def _verifychangelog(self):
        """verify the changelog of a repository

        The following checks are performed:
        - all of `_checkrevlog` checks,
        - all of `_checkentry` checks (for each revisions),
        - each revision can be read.

        The function returns some of the data observed in the changesets as a
        (mflinkrevs, filelinkrevs) tuples:
        - mflinkrevs:   is a { manifest-node -> [changelog-rev] } mapping
        - filelinkrevs: is a { file-path -> [changelog-rev] } mapping

        If a matcher was specified, filelinkrevs will only contains matched
        files.
        """
        ui = self.ui
        repo = self.repo
        match = self.match
        cl = repo.changelog

        ui.status(_(b"checking changesets\n"))
        mflinkrevs = {}
        filelinkrevs = {}
        seen = {}
        self._checkrevlog(cl, b"changelog", 0)
        progress = ui.makeprogress(
            _(b'checking'), unit=_(b'changesets'), total=len(repo)
        )
        for i in repo:
            progress.update(i)
            n = cl.node(i)
            self._checkentry(cl, i, n, seen, [i], b"changelog")

            try:
                changes = cl.read(n)
                if changes[0] != nullid:
                    mflinkrevs.setdefault(changes[0], []).append(i)
                    self.refersmf = True
                for f in changes[3]:
                    if match(f):
                        filelinkrevs.setdefault(_normpath(f), []).append(i)
            except Exception as inst:
                self.refersmf = True
                self._exc(i, _(b"unpacking changeset %s") % short(n), inst)
        progress.complete()
        return mflinkrevs, filelinkrevs

    def _verifymanifest(
        self, mflinkrevs, dir=b"", storefiles=None, subdirprogress=None
    ):
        """verify the manifestlog content

        Inputs:
        - mflinkrevs:     a {manifest-node -> [changelog-revisions]} mapping
        - dir:            a subdirectory to check (for tree manifest repo)
        - storefiles:     set of currently "orphan" files.
        - subdirprogress: a progress object

        This function checks:
        * all of `_checkrevlog` checks (for all manifest related revlogs)
        * all of `_checkentry` checks (for all manifest related revisions)
        * nodes for subdirectory exists in the sub-directory manifest
        * each manifest entries have a file path
        * each manifest node refered in mflinkrevs exist in the manifest log

        If tree manifest is in use and a matchers is specified, only the
        sub-directories matching it will be verified.

        return a two level mapping:
            {"path" -> { filenode -> changelog-revision}}

        This mapping primarily contains entries for every files in the
        repository. In addition, when tree-manifest is used, it also contains
        sub-directory entries.

        If a matcher is provided, only matching paths will be included.
        """
        repo = self.repo
        ui = self.ui
        match = self.match
        mfl = self.repo.manifestlog
        mf = mfl.getstorage(dir)

        if not dir:
            self.ui.status(_(b"checking manifests\n"))

        filenodes = {}
        subdirnodes = {}
        seen = {}
        label = b"manifest"
        if dir:
            label = dir
            revlogfiles = mf.files()
            storefiles.difference_update(revlogfiles)
            if subdirprogress:  # should be true since we're in a subdirectory
                subdirprogress.increment()
        if self.refersmf:
            # Do not check manifest if there are only changelog entries with
            # null manifests.
            self._checkrevlog(mf, label, 0)
        progress = ui.makeprogress(
            _(b'checking'), unit=_(b'manifests'), total=len(mf)
        )
        for i in mf:
            if not dir:
                progress.update(i)
            n = mf.node(i)
            lr = self._checkentry(mf, i, n, seen, mflinkrevs.get(n, []), label)
            if n in mflinkrevs:
                del mflinkrevs[n]
            elif dir:
                self._err(
                    lr,
                    _(b"%s not in parent-directory manifest") % short(n),
                    label,
                )
            else:
                self._err(lr, _(b"%s not in changesets") % short(n), label)

            try:
                mfdelta = mfl.get(dir, n).readdelta(shallow=True)
                for f, fn, fl in mfdelta.iterentries():
                    if not f:
                        self._err(lr, _(b"entry without name in manifest"))
                    elif f == b"/dev/null":  # ignore this in very old repos
                        continue
                    fullpath = dir + _normpath(f)
                    if fl == b't':
                        if not match.visitdir(fullpath):
                            continue
                        subdirnodes.setdefault(fullpath + b'/', {}).setdefault(
                            fn, []
                        ).append(lr)
                    else:
                        if not match(fullpath):
                            continue
                        filenodes.setdefault(fullpath, {}).setdefault(fn, lr)
            except Exception as inst:
                self._exc(lr, _(b"reading delta %s") % short(n), inst, label)
            if self._level >= VERIFY_FULL:
                try:
                    # Various issues can affect manifest. So we read each full
                    # text from storage. This triggers the checks from the core
                    # code (eg: hash verification, filename are ordered, etc.)
                    mfdelta = mfl.get(dir, n).read()
                except Exception as inst:
                    self._exc(
                        lr,
                        _(b"reading full manifest %s") % short(n),
                        inst,
                        label,
                    )

        if not dir:
            progress.complete()

        if self.havemf:
            # since we delete entry in `mflinkrevs` during iteration, any
            # remaining entries are "missing". We need to issue errors for them.
            changesetpairs = [(c, m) for m in mflinkrevs for c in mflinkrevs[m]]
            for c, m in sorted(changesetpairs):
                if dir:
                    self._err(
                        c,
                        _(
                            b"parent-directory manifest refers to unknown"
                            b" revision %s"
                        )
                        % short(m),
                        label,
                    )
                else:
                    self._err(
                        c,
                        _(b"changeset refers to unknown revision %s")
                        % short(m),
                        label,
                    )

        if not dir and subdirnodes:
            self.ui.status(_(b"checking directory manifests\n"))
            storefiles = set()
            subdirs = set()
            revlogv1 = self.revlogv1
            for f, f2, size in repo.store.datafiles():
                if not f:
                    self._err(None, _(b"cannot decode filename '%s'") % f2)
                elif (size > 0 or not revlogv1) and f.startswith(b'meta/'):
                    storefiles.add(_normpath(f))
                    subdirs.add(os.path.dirname(f))
            subdirprogress = ui.makeprogress(
                _(b'checking'), unit=_(b'manifests'), total=len(subdirs)
            )

        for subdir, linkrevs in pycompat.iteritems(subdirnodes):
            subdirfilenodes = self._verifymanifest(
                linkrevs, subdir, storefiles, subdirprogress
            )
            for f, onefilenodes in pycompat.iteritems(subdirfilenodes):
                filenodes.setdefault(f, {}).update(onefilenodes)

        if not dir and subdirnodes:
            subdirprogress.complete()
            if self.warnorphanstorefiles:
                for f in sorted(storefiles):
                    self._warn(_(b"warning: orphan data file '%s'") % f)

        return filenodes

    def _crosscheckfiles(self, filelinkrevs, filenodes):
        repo = self.repo
        ui = self.ui
        ui.status(_(b"crosschecking files in changesets and manifests\n"))

        total = len(filelinkrevs) + len(filenodes)
        progress = ui.makeprogress(
            _(b'crosschecking'), unit=_(b'files'), total=total
        )
        if self.havemf:
            for f in sorted(filelinkrevs):
                progress.increment()
                if f not in filenodes:
                    lr = filelinkrevs[f][0]
                    self._err(lr, _(b"in changeset but not in manifest"), f)

        if self.havecl:
            for f in sorted(filenodes):
                progress.increment()
                if f not in filelinkrevs:
                    try:
                        fl = repo.file(f)
                        lr = min([fl.linkrev(fl.rev(n)) for n in filenodes[f]])
                    except Exception:
                        lr = None
                    self._err(lr, _(b"in manifest but not in changeset"), f)

        progress.complete()

    def _verifyfiles(self, filenodes, filelinkrevs):
        repo = self.repo
        ui = self.ui
        lrugetctx = self.lrugetctx
        revlogv1 = self.revlogv1
        havemf = self.havemf
        ui.status(_(b"checking files\n"))

        storefiles = set()
        for f, f2, size in repo.store.datafiles():
            if not f:
                self._err(None, _(b"cannot decode filename '%s'") % f2)
            elif (size > 0 or not revlogv1) and f.startswith(b'data/'):
                storefiles.add(_normpath(f))

        state = {
            # TODO this assumes revlog storage for changelog.
            b'expectedversion': self.repo.changelog.version & 0xFFFF,
            b'skipflags': self.skipflags,
            # experimental config: censor.policy
            b'erroroncensored': ui.config(b'censor', b'policy') == b'abort',
        }

        files = sorted(set(filenodes) | set(filelinkrevs))
        revisions = 0
        progress = ui.makeprogress(
            _(b'checking'), unit=_(b'files'), total=len(files)
        )
        for i, f in enumerate(files):
            progress.update(i, item=f)
            try:
                linkrevs = filelinkrevs[f]
            except KeyError:
                # in manifest but not in changelog
                linkrevs = []

            if linkrevs:
                lr = linkrevs[0]
            else:
                lr = None

            try:
                fl = repo.file(f)
            except error.StorageError as e:
                self._err(lr, _(b"broken revlog! (%s)") % e, f)
                continue

            for ff in fl.files():
                try:
                    storefiles.remove(ff)
                except KeyError:
                    if self.warnorphanstorefiles:
                        self._warn(
                            _(b" warning: revlog '%s' not in fncache!") % ff
                        )
                        self.fncachewarned = True

            if not len(fl) and (self.havecl or self.havemf):
                self._err(lr, _(b"empty or missing %s") % f)
            else:
                # Guard against implementations not setting this.
                state[b'skipread'] = set()
                state[b'safe_renamed'] = set()

                for problem in fl.verifyintegrity(state):
                    if problem.node is not None:
                        linkrev = fl.linkrev(fl.rev(problem.node))
                    else:
                        linkrev = None

                    if problem.warning:
                        self._warn(problem.warning)
                    elif problem.error:
                        self._err(
                            linkrev if linkrev is not None else lr,
                            problem.error,
                            f,
                        )
                    else:
                        raise error.ProgrammingError(
                            b'problem instance does not set warning or error '
                            b'attribute: %s' % problem.msg
                        )

            seen = {}
            for i in fl:
                revisions += 1
                n = fl.node(i)
                lr = self._checkentry(fl, i, n, seen, linkrevs, f)
                if f in filenodes:
                    if havemf and n not in filenodes[f]:
                        self._err(lr, _(b"%s not in manifests") % (short(n)), f)
                    else:
                        del filenodes[f][n]

                if n in state[b'skipread'] and n not in state[b'safe_renamed']:
                    continue

                # check renames
                try:
                    # This requires resolving fulltext (at least on revlogs,
                    # though not with LFS revisions). We may want
                    # ``verifyintegrity()`` to pass a set of nodes with
                    # rename metadata as an optimization.
                    rp = fl.renamed(n)
                    if rp:
                        if lr is not None and ui.verbose:
                            ctx = lrugetctx(lr)
                            if not any(rp[0] in pctx for pctx in ctx.parents()):
                                self._warn(
                                    _(
                                        b"warning: copy source of '%s' not"
                                        b" in parents of %s"
                                    )
                                    % (f, ctx)
                                )
                        fl2 = repo.file(rp[0])
                        if not len(fl2):
                            self._err(
                                lr,
                                _(
                                    b"empty or missing copy source revlog "
                                    b"%s:%s"
                                )
                                % (rp[0], short(rp[1])),
                                f,
                            )
                        elif rp[1] == nullid:
                            ui.note(
                                _(
                                    b"warning: %s@%s: copy source"
                                    b" revision is nullid %s:%s\n"
                                )
                                % (f, lr, rp[0], short(rp[1]))
                            )
                        else:
                            fl2.rev(rp[1])
                except Exception as inst:
                    self._exc(
                        lr, _(b"checking rename of %s") % short(n), inst, f
                    )

            # cross-check
            if f in filenodes:
                fns = [(v, k) for k, v in pycompat.iteritems(filenodes[f])]
                for lr, node in sorted(fns):
                    self._err(
                        lr,
                        _(b"manifest refers to unknown revision %s")
                        % short(node),
                        f,
                    )
        progress.complete()

        if self.warnorphanstorefiles:
            for f in sorted(storefiles):
                self._warn(_(b"warning: orphan data file '%s'") % f)

        return len(files), revisions