tests/test-blackbox.t

revlog: automatically read from opened file handles

The revlog reading code commonly opens a new file handle for
reading on demand. There is support for passing a file handle
to revlog.revision(). But it is marked as an internal argument.

When revlogs are written, we write() data as it is available. But
we don't flush() data until all revisions are written.

Putting these two traits together, it is possible for an in-process
revlog reader during active writes to trigger the opening of a new
file handle on a file with unflushed writes. The reader won't have
access to all "available" revlog data (as it hasn't been flushed).
And with the introduction of the previous patch, this can lead to
the revlog raising an error due to a partial read.

I witnessed this behavior when applying changegroup data (via
`hg pull`) before issue6006 was fixed via different means. Having
this and the previous patch in play would have helped cause errors
earlier rather than manifesting as hash verification failures.

While this has been a long-standing issue, I believe the relatively
new delta computation code has tickled it into being more common.
This is because the new delta computation code will compute deltas
in more scenarios. This can lead to revlog reading. While the delta
computation code is probably supposed to reuse file handles, it
appears it isn't doing so in all circumstances.

But the issue runs deeper than that. Theoretically, any code can
access revision data during revlog writes. It appears we were just
getting lucky that it wasn't. (The "add revision callback" passed to
addgroup() provides an avenue to do this.)

If I changed the revlog's behavior to not cache the full revision
text or to clear caches after revision insertion during addgroup(),
I was able to produce crashes 100% of the time when writing changelog
revisions. This is because changelog's add revision callback attempts
to resolve the revision data to access the changed files list. And
without the revision's fulltext being cached, we performed a revlog
read, which required opening a new file handle. This attempted to read
unflushed data, leading to a partial read and a crash.

This commit teaches the revlog to store the file handles used for
writing multiple revisions during addgroup(). It also teaches the
code for resolving a file handle when reading to use these handles,
if available. This ensures that *any* reads (regardless of their
source) use the active writing file handles, if available. These
file handles have access to the unflushed data because they wrote it.
This allows reads to complete without issue.

Differential Revision: https://phab.mercurial-scm.org/D5267

setup

  $ cat > myextension.py <<EOF
  > from mercurial import error, registrar
  > cmdtable = {}
  > command = registrar.command(cmdtable)
  > @command(b'crash', [], b'hg crash')
  > def crash(ui, *args, **kwargs):
  >     raise Exception("oops")
  > @command(b'abort', [], b'hg abort')
  > def abort(ui, *args, **kwargs):
  >     raise error.Abort(b"oops")
  > EOF
  $ abspath=`pwd`/myextension.py

  $ cat >> $HGRCPATH <<EOF
  > [extensions]
  > blackbox=
  > mock=$TESTDIR/mockblackbox.py
  > mq=
  > myextension=$TESTTMP/myextension.py
  > [alias]
  > confuse = log --limit 3
  > so-confusing = confuse --style compact
  > EOF

  $ hg init blackboxtest
  $ cd blackboxtest

command, exit codes, and duration

  $ echo a > a
  $ hg add a
  $ hg blackbox --config blackbox.dirty=True
  1970/01/01 00:00:00 bob @0000000000000000000000000000000000000000 (5000)> init blackboxtest exited 0 after * seconds (glob)
  1970/01/01 00:00:00 bob @0000000000000000000000000000000000000000 (5000)> add a
  1970/01/01 00:00:00 bob @0000000000000000000000000000000000000000 (5000)> add a exited 0 after * seconds (glob)
  1970/01/01 00:00:00 bob @0000000000000000000000000000000000000000+ (5000)> blackbox --config *blackbox.dirty=True* (glob)

failure exit code
  $ rm ./.hg/blackbox.log
  $ hg add non-existent
  non-existent: $ENOENT$
  [1]
  $ hg blackbox
  1970/01/01 00:00:00 bob @0000000000000000000000000000000000000000 (5000)> add non-existent
  1970/01/01 00:00:00 bob @0000000000000000000000000000000000000000 (5000)> add non-existent exited 1 after * seconds (glob)
  1970/01/01 00:00:00 bob @0000000000000000000000000000000000000000 (5000)> blackbox

abort exit code
  $ rm ./.hg/blackbox.log
  $ hg abort 2> /dev/null
  [255]
  $ hg blackbox -l 2
  1970/01/01 00:00:00 bob @0000000000000000000000000000000000000000 (5000)> abort exited 255 after * seconds (glob)
  1970/01/01 00:00:00 bob @0000000000000000000000000000000000000000 (5000)> blackbox -l 2

unhandled exception
  $ rm ./.hg/blackbox.log
  $ hg crash 2> /dev/null
  [1]
  $ hg blackbox -l 2
  1970/01/01 00:00:00 bob @0000000000000000000000000000000000000000 (5000)> crash exited 1 after * seconds (glob)
  1970/01/01 00:00:00 bob @0000000000000000000000000000000000000000 (5000)> blackbox -l 2

alias expansion is logged
  $ rm ./.hg/blackbox.log
  $ hg confuse
  $ hg blackbox
  1970/01/01 00:00:00 bob @0000000000000000000000000000000000000000 (5000)> confuse
  1970/01/01 00:00:00 bob @0000000000000000000000000000000000000000 (5000)> alias 'confuse' expands to 'log --limit 3'
  1970/01/01 00:00:00 bob @0000000000000000000000000000000000000000 (5000)> confuse exited 0 after * seconds (glob)
  1970/01/01 00:00:00 bob @0000000000000000000000000000000000000000 (5000)> blackbox

recursive aliases work correctly
  $ rm ./.hg/blackbox.log
  $ hg so-confusing
  $ hg blackbox
  1970/01/01 00:00:00 bob @0000000000000000000000000000000000000000 (5000)> so-confusing
  1970/01/01 00:00:00 bob @0000000000000000000000000000000000000000 (5000)> alias 'so-confusing' expands to 'confuse --style compact'
  1970/01/01 00:00:00 bob @0000000000000000000000000000000000000000 (5000)> alias 'confuse' expands to 'log --limit 3'
  1970/01/01 00:00:00 bob @0000000000000000000000000000000000000000 (5000)> so-confusing exited 0 after * seconds (glob)
  1970/01/01 00:00:00 bob @0000000000000000000000000000000000000000 (5000)> blackbox

custom date format
  $ rm ./.hg/blackbox.log
  $ hg --config blackbox.date-format='%Y-%m-%d @ %H:%M:%S' \
  >    --config devel.default-date='1334347993 0' --traceback status
  A a
  $ hg blackbox
  2012-04-13 @ 20:13:13 bob @0000000000000000000000000000000000000000 (5000)> --config *blackbox.date-format=%Y-%m-%d @ %H:%M:%S* --config *devel.default-date=1334347993 0* --traceback status (glob)
  2012-04-13 @ 20:13:13 bob @0000000000000000000000000000000000000000 (5000)> --config *blackbox.date-format=%Y-%m-%d @ %H:%M:%S* --config *devel.default-date=1334347993 0* --traceback status exited 0 after * seconds (glob)
  1970/01/01 00:00:00 bob @0000000000000000000000000000000000000000 (5000)> blackbox

incoming change tracking

create two heads to verify that we only see one change in the log later
  $ hg commit -ma
  $ hg up null
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ echo b > b
  $ hg commit -Amb
  adding b
  created new head

clone, commit, pull
  $ hg clone . ../blackboxtest2
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ echo c > c
  $ hg commit -Amc
  adding c
  $ cd ../blackboxtest2
  $ hg pull
  pulling from $TESTTMP/blackboxtest
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files
  new changesets d02f48003e62
  (run 'hg update' to get a working copy)
  $ hg blackbox -l 6
  1970/01/01 00:00:00 bob @6563da9dcf87b1949716e38ff3e3dfaa3198eb06 (5000)> pull
  1970/01/01 00:00:00 bob @6563da9dcf87b1949716e38ff3e3dfaa3198eb06 (5000)> updated served branch cache in * seconds (glob)
  1970/01/01 00:00:00 bob @6563da9dcf87b1949716e38ff3e3dfaa3198eb06 (5000)> wrote served branch cache with 1 labels and 2 nodes
  1970/01/01 00:00:00 bob @6563da9dcf87b1949716e38ff3e3dfaa3198eb06 (5000)> 1 incoming changes - new heads: d02f48003e62
  1970/01/01 00:00:00 bob @6563da9dcf87b1949716e38ff3e3dfaa3198eb06 (5000)> pull exited 0 after * seconds (glob)
  1970/01/01 00:00:00 bob @6563da9dcf87b1949716e38ff3e3dfaa3198eb06 (5000)> blackbox -l 6

we must not cause a failure if we cannot write to the log

  $ hg rollback
  repository tip rolled back to revision 1 (undo pull)

  $ mv .hg/blackbox.log .hg/blackbox.log-
  $ mkdir .hg/blackbox.log
  $ hg --debug incoming
  warning: cannot write to blackbox.log: * (glob)
  comparing with $TESTTMP/blackboxtest
  query 1; heads
  searching for changes
  all local heads known remotely
  changeset:   2:d02f48003e62c24e2659d97d30f2a83abe5d5d51
  tag:         tip
  phase:       draft
  parent:      1:6563da9dcf87b1949716e38ff3e3dfaa3198eb06
  parent:      -1:0000000000000000000000000000000000000000
  manifest:    2:ab9d46b053ebf45b7996f2922b9893ff4b63d892
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  files+:      c
  extra:       branch=default
  description:
  c
  
  
  $ hg pull
  pulling from $TESTTMP/blackboxtest
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files
  new changesets d02f48003e62
  (run 'hg update' to get a working copy)

a failure reading from the log is fatal

  $ hg blackbox -l 3
  abort: *$TESTTMP/blackboxtest2/.hg/blackbox.log* (glob)
  [255]

  $ rmdir .hg/blackbox.log
  $ mv .hg/blackbox.log- .hg/blackbox.log

backup bundles get logged

  $ touch d
  $ hg commit -Amd
  adding d
  created new head
  $ hg strip tip
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  saved backup bundle to $TESTTMP/blackboxtest2/.hg/strip-backup/*-backup.hg (glob)
  $ hg blackbox -l 6
  1970/01/01 00:00:00 bob @73f6ee326b27d820b0472f1a825e3a50f3dc489b (5000)> strip tip
  1970/01/01 00:00:00 bob @6563da9dcf87b1949716e38ff3e3dfaa3198eb06 (5000)> saved backup bundle to $TESTTMP/blackboxtest2/.hg/strip-backup/73f6ee326b27-7612e004-backup.hg
  1970/01/01 00:00:00 bob @6563da9dcf87b1949716e38ff3e3dfaa3198eb06 (5000)> updated base branch cache in * seconds (glob)
  1970/01/01 00:00:00 bob @6563da9dcf87b1949716e38ff3e3dfaa3198eb06 (5000)> wrote base branch cache with 1 labels and 2 nodes
  1970/01/01 00:00:00 bob @6563da9dcf87b1949716e38ff3e3dfaa3198eb06 (5000)> strip tip exited 0 after * seconds (glob)
  1970/01/01 00:00:00 bob @6563da9dcf87b1949716e38ff3e3dfaa3198eb06 (5000)> blackbox -l 6

extension and python hooks - use the eol extension for a pythonhook

  $ echo '[extensions]' >> .hg/hgrc
  $ echo 'eol=' >> .hg/hgrc
  $ echo '[hooks]' >> .hg/hgrc
  $ echo 'update = echo hooked' >> .hg/hgrc
  $ hg update
  The fsmonitor extension is incompatible with the eol extension and has been disabled. (fsmonitor !)
  hooked
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  updated to "d02f48003e62: c"
  1 other heads for branch "default"
  $ cat >> .hg/hgrc <<EOF
  > [extensions]
  > # disable eol, because it is not needed for subsequent tests
  > # (in addition, keeping it requires extra care for fsmonitor)
  > eol=!
  > EOF
  $ hg blackbox -l 5
  1970/01/01 00:00:00 bob @6563da9dcf87b1949716e38ff3e3dfaa3198eb06 (5000)> update (no-chg !)
  1970/01/01 00:00:00 bob @6563da9dcf87b1949716e38ff3e3dfaa3198eb06 (5000)> pythonhook-preupdate: hgext.eol.preupdate finished in * seconds (glob)
  1970/01/01 00:00:00 bob @d02f48003e62c24e2659d97d30f2a83abe5d5d51 (5000)> exthook-update: echo hooked finished in * seconds (glob)
  1970/01/01 00:00:00 bob @d02f48003e62c24e2659d97d30f2a83abe5d5d51 (5000)> update exited 0 after * seconds (glob)
  1970/01/01 00:00:00 bob @d02f48003e62c24e2659d97d30f2a83abe5d5d51 (5000)> serve --cmdserver chgunix --address $TESTTMP.chgsock/server.* --daemon-postexec 'chdir:/' (glob) (chg !)
  1970/01/01 00:00:00 bob @d02f48003e62c24e2659d97d30f2a83abe5d5d51 (5000)> blackbox -l 5

log rotation

  $ echo '[blackbox]' >> .hg/hgrc
  $ echo 'maxsize = 20 b' >> .hg/hgrc
  $ echo 'maxfiles = 3' >> .hg/hgrc
  $ hg status
  $ hg status
  $ hg status
  $ hg tip -q
  2:d02f48003e62
  $ ls .hg/blackbox.log*
  .hg/blackbox.log
  .hg/blackbox.log.1
  .hg/blackbox.log.2
  $ cd ..

  $ hg init blackboxtest3
  $ cd blackboxtest3
  $ hg blackbox
  1970/01/01 00:00:00 bob @0000000000000000000000000000000000000000 (5000)> init blackboxtest3 exited 0 after * seconds (glob)
  1970/01/01 00:00:00 bob @0000000000000000000000000000000000000000 (5000)> blackbox
  $ mv .hg/blackbox.log .hg/blackbox.log-
  $ mkdir .hg/blackbox.log
  $ sed -e 's/\(.*test1.*\)/#\1/; s#\(.*commit2.*\)#os.rmdir(".hg/blackbox.log")\
  > os.rename(".hg/blackbox.log-", ".hg/blackbox.log")\
  > \1#' $TESTDIR/test-dispatch.py > ../test-dispatch.py
  $ "$PYTHON" $TESTDIR/blackbox-readonly-dispatch.py
  running: --debug add foo
  warning: cannot write to blackbox.log: Is a directory (no-windows !)
  warning: cannot write to blackbox.log: $TESTTMP/blackboxtest3/.hg/blackbox.log: Access is denied (windows !)
  adding foo
  result: 0
  running: --debug commit -m commit1 -d 2000-01-01 foo
  warning: cannot write to blackbox.log: Is a directory (no-windows !)
  warning: cannot write to blackbox.log: $TESTTMP/blackboxtest3/.hg/blackbox.log: Access is denied (windows !)
  committing files:
  foo
  committing manifest
  committing changelog
  updating the branch cache
  committed changeset 0:0e46349438790c460c5c9f7546bfcd39b267bbd2
  result: 0
  running: --debug commit -m commit2 -d 2000-01-02 foo
  committing files:
  foo
  committing manifest
  committing changelog
  updating the branch cache
  committed changeset 1:45589e459b2edfbf3dbde7e01f611d2c1e7453d7
  result: 0
  running: --debug log -r 0
  changeset:   0:0e46349438790c460c5c9f7546bfcd39b267bbd2
  phase:       draft
  parent:      -1:0000000000000000000000000000000000000000
  parent:      -1:0000000000000000000000000000000000000000
  manifest:    0:9091aa5df980aea60860a2e39c95182e68d1ddec
  user:        test
  date:        Sat Jan 01 00:00:00 2000 +0000
  files+:      foo
  extra:       branch=default
  description:
  commit1
  
  
  result: 0
  running: --debug log -r tip
  changeset:   1:45589e459b2edfbf3dbde7e01f611d2c1e7453d7
  tag:         tip
  phase:       draft
  parent:      0:0e46349438790c460c5c9f7546bfcd39b267bbd2
  parent:      -1:0000000000000000000000000000000000000000
  manifest:    1:895aa9b7886f89dd017a6d62524e1f9180b04df9
  user:        test
  date:        Sun Jan 02 00:00:00 2000 +0000
  files:       foo
  extra:       branch=default
  description:
  commit2
  
  
  result: 0
  $ hg blackbox
  1970/01/01 00:00:00 bob @45589e459b2edfbf3dbde7e01f611d2c1e7453d7 (5000)> updating the branch cache
  1970/01/01 00:00:00 bob @45589e459b2edfbf3dbde7e01f611d2c1e7453d7 (5000)> updated served branch cache in * seconds (glob)
  1970/01/01 00:00:00 bob @45589e459b2edfbf3dbde7e01f611d2c1e7453d7 (5000)> wrote served branch cache with 1 labels and 1 nodes
  1970/01/01 00:00:00 bob @45589e459b2edfbf3dbde7e01f611d2c1e7453d7 (5000)> --debug commit -m commit2 -d 2000-01-02 foo exited 0 after *.?? seconds (glob)
  1970/01/01 00:00:00 bob @45589e459b2edfbf3dbde7e01f611d2c1e7453d7 (5000)> --debug log -r 0
  1970/01/01 00:00:00 bob @45589e459b2edfbf3dbde7e01f611d2c1e7453d7 (5000)> writing .hg/cache/tags2-visible with 0 tags
  1970/01/01 00:00:00 bob @45589e459b2edfbf3dbde7e01f611d2c1e7453d7 (5000)> --debug log -r 0 exited 0 after *.?? seconds (glob)
  1970/01/01 00:00:00 bob @45589e459b2edfbf3dbde7e01f611d2c1e7453d7 (5000)> --debug log -r tip
  1970/01/01 00:00:00 bob @45589e459b2edfbf3dbde7e01f611d2c1e7453d7 (5000)> --debug log -r tip exited 0 after *.?? seconds (glob)
  1970/01/01 00:00:00 bob @45589e459b2edfbf3dbde7e01f611d2c1e7453d7 (5000)> blackbox

Test log recursion from dirty status check

  $ cat > ../r.py <<EOF
  > from mercurial import context, error, extensions
  > x=[False]
  > def status(orig, *args, **opts):
  >     args[0].repo().ui.log(b"broken", b"recursion?")
  >     return orig(*args, **opts)
  > def reposetup(ui, repo):
  >     extensions.wrapfunction(context.basectx, 'status', status)
  > EOF
  $ hg id --config extensions.x=../r.py --config blackbox.dirty=True
  45589e459b2e tip

cleanup
  $ cd ..

#if chg

when using chg, blackbox.log should get rotated correctly

  $ cat > $TESTTMP/noop.py << EOF
  > from __future__ import absolute_import
  > import time
  > from mercurial import registrar, scmutil
  > cmdtable = {}
  > command = registrar.command(cmdtable)
  > @command('noop')
  > def noop(ui, repo):
  >     pass
  > EOF

  $ hg init blackbox-chg
  $ cd blackbox-chg

  $ cat > .hg/hgrc << EOF
  > [blackbox]
  > maxsize = 500B
  > [extensions]
  > # extension change forces chg to restart
  > noop=$TESTTMP/noop.py
  > EOF

  $ "$PYTHON" -c 'print("a" * 400)' > .hg/blackbox.log
  $ chg noop
  $ chg noop
  $ chg noop
  $ chg noop
  $ chg noop

  $ cat > showsize.py << 'EOF'
  > import os
  > import sys
  > limit = 500
  > for p in sys.argv[1:]:
  >     size = os.stat(p).st_size
  >     if size >= limit:
  >         desc = '>='
  >     else:
  >         desc = '<'
  >     print('%s: %s %d' % (p, desc, limit))
  > EOF

  $ "$PYTHON" showsize.py .hg/blackbox*
  .hg/blackbox.log: < 500
  .hg/blackbox.log.1: >= 500
  .hg/blackbox.log.2: >= 500

  $ cd ..

With chg, blackbox should not create the log file if the repo is gone

  $ hg init repo1
  $ hg --config extensions.a=! -R repo1 log
  $ rm -rf $TESTTMP/repo1
  $ hg --config extensions.a=! init repo1

#endif

blackbox should work if repo.ui.log is not called (issue5518)

  $ cat > $TESTTMP/raise.py << EOF
  > from __future__ import absolute_import
  > from mercurial import registrar, scmutil
  > cmdtable = {}
  > command = registrar.command(cmdtable)
  > @command(b'raise')
  > def raisecmd(*args):
  >     raise RuntimeError('raise')
  > EOF

  $ cat >> $HGRCPATH << EOF
  > [blackbox]
  > track = commandexception
  > [extensions]
  > raise=$TESTTMP/raise.py
  > EOF

  $ hg init $TESTTMP/blackbox-exception-only
  $ cd $TESTTMP/blackbox-exception-only

#if chg
 (chg exits 255 because it fails to receive an exit code)
  $ hg raise 2>/dev/null
  [255]
#else
 (hg exits 1 because Python default exit code for uncaught exception is 1)
  $ hg raise 2>/dev/null
  [1]
#endif

  $ head -1 .hg/blackbox.log
  1970/01/01 00:00:00 bob @0000000000000000000000000000000000000000 (5000)> ** Unknown exception encountered with possibly-broken third-party extension mock
  $ tail -2 .hg/blackbox.log
  RuntimeError: raise