view tests/common-pattern.py @ 46607:e9901d01d135

revlog: add a mechanism to verify expected file position before appending

If someone uses `hg debuglocks`, or some non-hg process writes to the .hg
directory without respecting the locks, or if the repo's on a networked
filesystem, it's possible for the revlog code to write out corrupted data.

The form of this corruption can vary depending on what data was written and how
that happened. We are in the "networked filesystem" case (though I've had users
also do this to themselves with the "`hg debuglocks`" scenario), and most often
see this with the changelog. What ends up happening is we produce two items
(let's call them rev1 and rev2) in the .i file that have the same linkrev,
baserev, and offset into the .d file, while the data in the .d file is appended
properly. rev2's compressed_size is accurate for rev2, but when we go to
decompress the data in the .d file, we use the offset that's recorded in the
index file, which is the same as rev1, and attempt to decompress
rev2.compressed_size bytes of rev1's data. This usually does not succeed. :)

When using inline data, this also fails, though I haven't investigated why too
closely. This shows up as a "patch decode" error. I believe what's happening
there is that we're basically ignoring the offset field, getting the data
properly, but since baserev != rev, it thinks this is a delta based on rev
(instead of a full text) and can't actually apply it as such.

For now, I'm going to make this an optional component and default it to entirely
off. I may increase the default severity of this in the future, once I've
enabled it for my users and we gain more experience with it. Luckily, most of my
users have a versioned filesystem and can roll back to before the corruption has
been written, it's just a hassle to do so and not everyone knows how (so it's a
support burden). Users on other filesystems will not have that luxury, and this
can cause them to have a corrupted repository that they are unlikely to know how
to resolve, and they'll see this as a data-loss event. Refusing to create the
corruption is a much better user experience.

This mechanism is not perfect. There may be false-negatives (racy writes that
are not detected). There should not be any false-positives (non-racy writes that
are detected as such). This is not a mechanism that makes putting a repo on a
networked filesystem "safe" or "supported", just *less* likely to cause
corruption.

Differential Revision: https://phab.mercurial-scm.org/D9952

# common patterns in test at can safely be replaced
from __future__ import absolute_import

import os

substitutions = [
    # list of possible compressions
    (br'(zstd,)?zlib,none,bzip2', br'$USUAL_COMPRESSIONS$'),
    (br'=(zstd,)?zlib', br'=$BUNDLE2_COMPRESSIONS$'),
    # capabilities sent through http
    (
        br'bundlecaps=HG20%2Cbundle2%3DHG20%250A'
        br'bookmarks%250A'
        br'changegroup%253D01%252C02%250A'
        br'checkheads%253Drelated%250A'
        br'digests%253Dmd5%252Csha1%252Csha512%250A'
        br'error%253Dabort%252Cunsupportedcontent%252Cpushraced%252Cpushkey%250A'
        br'hgtagsfnodes%250A'
        br'listkeys%250A'
        br'phases%253Dheads%250A'
        br'pushkey%250A'
        br'remote-changegroup%253Dhttp%252Chttps%250A'
        br'rev-branch-cache%250A'
        br'stream%253Dv2',
        # (the replacement patterns)
        br'$USUAL_BUNDLE_CAPS$',
    ),
    (
        br'bundlecaps=HG20%2Cbundle2%3DHG20%250A'
        br'bookmarks%250A'
        br'changegroup%253D01%252C02%250A'
        br'checkheads%3Drelated%0A'
        br'digests%253Dmd5%252Csha1%252Csha512%250A'
        br'error%253Dabort%252Cunsupportedcontent%252Cpushraced%252Cpushkey%250A'
        br'hgtagsfnodes%250A'
        br'listkeys%250A'
        br'phases%253Dheads%250A'
        br'pushkey%250A'
        br'remote-changegroup%253Dhttp%252Chttps',
        # (the replacement patterns)
        br'$USUAL_BUNDLE_CAPS_SERVER$',
    ),
    # bundle2 capabilities sent through ssh
    (
        br'bundle2=HG20%0A'
        br'bookmarks%0A'
        br'changegroup%3D01%2C02%0A'
        br'checkheads%3Drelated%0A'
        br'digests%3Dmd5%2Csha1%2Csha512%0A'
        br'error%3Dabort%2Cunsupportedcontent%2Cpushraced%2Cpushkey%0A'
        br'hgtagsfnodes%0A'
        br'listkeys%0A'
        br'phases%3Dheads%0A'
        br'pushkey%0A'
        br'remote-changegroup%3Dhttp%2Chttps%0A'
        br'rev-branch-cache%0A'
        br'stream%3Dv2',
        # (replacement patterns)
        br'$USUAL_BUNDLE2_CAPS$',
    ),
    # bundle2 capabilities advertised by the server
    (
        br'bundle2=HG20%0A'
        br'bookmarks%0A'
        br'changegroup%3D01%2C02%0A'
        br'checkheads%3Drelated%0A'
        br'digests%3Dmd5%2Csha1%2Csha512%0A'
        br'error%3Dabort%2Cunsupportedcontent%2Cpushraced%2Cpushkey%0A'
        br'hgtagsfnodes%0A'
        br'listkeys%0A'
        br'phases%3Dheads%0A'
        br'pushkey%0A'
        br'remote-changegroup%3Dhttp%2Chttps%0A'
        br'rev-branch-cache',
        # (replacement patterns)
        br'$USUAL_BUNDLE2_CAPS_SERVER$',
    ),
    (
        br'bundle2=HG20%0A'
        br'bookmarks%0A'
        br'changegroup%3D01%2C02%0A'
        br'digests%3Dmd5%2Csha1%2Csha512%0A'
        br'error%3Dabort%2Cunsupportedcontent%2Cpushraced%2Cpushkey%0A'
        br'hgtagsfnodes%0A'
        br'listkeys%0A'
        br'pushkey%0A'
        br'remote-changegroup%3Dhttp%2Chttps%0A'
        br'rev-branch-cache%0A'
        br'stream%3Dv2',
        # (replacement patterns)
        br'$USUAL_BUNDLE2_CAPS_NO_PHASES$',
    ),
    # HTTP access log dates
    (
        br' - - \[\d\d/.../2\d\d\d \d\d:\d\d:\d\d] "(GET|PUT|POST)',
        lambda m: br' - - [$LOGDATE$] "' + m.group(1),
    ),
    # HTTP error log dates
    (
        br' - - \[\d\d/.../2\d\d\d \d\d:\d\d:\d\d] (HG error:|Exception)',
        lambda m: br' - - [$ERRDATE$] ' + m.group(1),
    ),
    # HTTP header dates- RFC 1123
    (
        br'([Dd]ate): [A-Za-z]{3}, \d\d [A-Za-z]{3} \d{4} \d\d:\d\d:\d\d GMT',
        lambda m: br'%s: $HTTP_DATE$' % m.group(1),
    ),
    # LFS expiration value
    (
        br'"expires_at": "\d{4}-\d\d-\d\dT\d\d:\d\d:\d\dZ"',
        br'"expires_at": "$ISO_8601_DATE_TIME$"',
    ),
    # Windows has an extra '/' in the following lines that get globbed away:
    #   pushing to file:/*/$TESTTMP/r2 (glob)
    #   comparing with file:/*/$TESTTMP/r2 (glob)
    #   sub/maybelarge.dat: largefile 34..9c not available from
    #       file:/*/$TESTTMP/largefiles-repo (glob)
    (
        br'(.*file:/)/?(/\$TESTTMP.*)',
        lambda m: m.group(1) + b'*' + m.group(2) + b' (glob)',
    ),
]

# Various platform error strings, keyed on a common replacement string
_errors = {
    br'$ENOENT$': (
        # IOError in Python does not have the same error message
        # than in Rust, and automatic conversion is not possible
        # because of module member privacy.
        br'No such file or directory \(os error 2\)',
        # strerror()
        br'No such file or directory',
        # FormatMessage(ERROR_FILE_NOT_FOUND)
        br'The system cannot find the file specified',
    ),
    br'$ENOTDIR$': (
        # strerror()
        br'Not a directory',
        # FormatMessage(ERROR_PATH_NOT_FOUND)
        br'The system cannot find the path specified',
    ),
    br'$ECONNRESET$': (
        # strerror()
        br'Connection reset by peer',
        # FormatMessage(WSAECONNRESET)
        br'An existing connection was forcibly closed by the remote host',
    ),
    br'$EADDRINUSE$': (
        # strerror()
        br'Address already in use',
        # FormatMessage(WSAEADDRINUSE)
        br'Only one usage of each socket address'
        br' \(protocol/network address/port\) is normally permitted',
    ),
    br'$EADDRNOTAVAIL$': (
        # strerror()
        br'Cannot assign requested address',
        # FormatMessage(WSAEADDRNOTAVAIL)
    ),
}

for replace, msgs in _errors.items():
    substitutions.extend((m, replace) for m in msgs)

# Output lines on Windows that can be autocorrected for '\' vs '/' path
# differences.
_winpathfixes = [
    # cloning subrepo s\ss from $TESTTMP/t/s/ss
    # cloning subrepo foo\bar from http://localhost:$HGPORT/foo/bar
    br'(?m)^cloning subrepo \S+\\.*',
    # pulling from $TESTTMP\issue1852a
    br'(?m)^pulling from \$TESTTMP\\.*',
    # pushing to $TESTTMP\a
    br'(?m)^pushing to \$TESTTMP\\.*',
    # pushing subrepo s\ss to $TESTTMP/t/s/ss
    br'(?m)^pushing subrepo \S+\\\S+ to.*',
    # moving d1\d11\a1 to d3/d11/a1
    br'(?m)^moving \S+\\.*',
    # d1\a: not recording move - dummy does not exist
    br'\S+\\\S+: not recording move .+',
    # reverting s\a
    br'(?m)^reverting (?!subrepo ).*\\.*',
    # saved backup bundle to
    #     $TESTTMP\test\.hg\strip-backup/443431ffac4f-2fc5398a-backup.hg
    br'(?m)^saved backup bundle to \$TESTTMP.*\.hg',
    # no changes made to subrepo s\ss since last push to ../tcc/s/ss
    br'(?m)^no changes made to subrepo \S+\\\S+ since.*',
    # changeset 5:9cc5aa7204f0: stuff/maybelarge.dat references missing
    #     $TESTTMP\largefiles-repo-hg\.hg\largefiles\76..38
    br'(?m)^changeset .* references (corrupted|missing) \$TESTTMP\\.*',
    # stuff/maybelarge.dat: largefile 76..38 not available from
    #     file:/*/$TESTTMP\largefiles-repo (glob)
    br'.*: largefile \S+ not available from file:/\*/.+',
]

if os.name == 'nt':
    substitutions.extend(
        [
            (s, lambda match: match.group().replace(b'\\', b'/'))
            for s in _winpathfixes
        ]
    )