view tests/test-transaction-rollback-on-revlog-split.t @ 49275:c6a3243567b6

chg: replace mercurial.util.recvfds() by simpler pure Python implementation On Python 3, we have socket.socket.recvmsg(). This makes it possible to receive FDs in pure Python code. The new code behaves like the previous implementations, except that it’s more strict about the format of the ancillary data. This works because we know in which format the FDs are passed. Because the code is (and always has been) specific to chg (payload is 1 byte, number of passed FDs is limited) and we now have only one implementation and the code is very short, I decided to stop exposing a function in mercurial.util. Note on terminology: The SCM_RIGHTS mechanism is used to share open file descriptions to another process over a socket. The sending side passes an array of file descriptors and the receiving side receives an array of file descriptors. The file descriptors are different in general on both sides but refer to the same open file descriptions. The two terms are often conflated, even in the official documentation. That’s why I used “FD” above, which could mean both “file descriptor” and “file description”.
author Manuel Jacob <me@manueljacob.de>
date Thu, 02 Jun 2022 23:57:56 +0200
parents ccd9cb73125c
children e2ba2234bf1c
line wrap: on
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Test correctness of revlog inline -> non-inline transition
----------------------------------------------------------

Helper extension to intercept renames.

  $ cat > $TESTTMP/intercept_rename.py << EOF
  > import os
  > import sys
  > from mercurial import extensions, util
  > 
  > def extsetup(ui):
  >     def close(orig, *args, **kwargs):
  >         path = util.normpath(args[0]._atomictempfile__name)
  >         if path.endswith(b'/.hg/store/data/file.i'):
  >             os._exit(80)
  >         return orig(*args, **kwargs)
  >     extensions.wrapfunction(util.atomictempfile, 'close', close)
  > EOF

Test offset computation to correctly factor in the index entries themselves.
Also test that the new data size has the correct size if the transaction is aborted
after the index has been replaced.

Test repo has commits a, b, c, D, where D is large (grows the revlog enough that it
transitions to non-inline storage). The clone initially has changes a, b
and will transition to non-inline storage when adding c, D.

If the transaction adding c, D is rolled back, then we don't undo the revlog split,
but truncate the index and the data to remove both c and D.

  $ hg init troffset-computation --config format.revlog-compression=none
  $ cd troffset-computation
  $ printf '%20d' '1' > file
  $ hg commit -Aqma
  $ printf '%1024d' '1' > file
  $ hg commit -Aqmb
  $ printf '%20d' '1' > file
  $ hg commit -Aqmc
  $ dd if=/dev/zero of=file bs=1k count=128 > /dev/null 2>&1
  $ hg commit -AqmD

  $ cd ..

  $ hg clone -r 1 troffset-computation troffset-computation-copy --config format.revlog-compression=none -q
  $ cd troffset-computation-copy

Reference size:

  $ f -s .hg/store/data/file*
  .hg/store/data/file.i: size=1174

  $ cat > .hg/hgrc <<EOF
  > [hooks]
  > pretxnchangegroup = python:$TESTDIR/helper-killhook.py:killme
  > EOF
#if chg
  $ hg pull ../troffset-computation
  pulling from ../troffset-computation
  [255]
#else
  $ hg pull ../troffset-computation
  pulling from ../troffset-computation
  [80]
#endif
  $ cat .hg/store/journal | tr -s '\000' ' ' | grep data/file | tail -1
  data/file.i 128

The first file.i entry should match the "Reference size" above.
The first file.d entry is the temporary record during the split,
the second entry after the split happened. The sum of the second file.d
and the second file.i entry should match the first file.i entry.

  $ cat .hg/store/journal | tr -s '\000' ' ' | grep data/file
  data/file.i 1174
  data/file.d 0
  data/file.d 1046
  data/file.i 128
  $ hg recover
  rolling back interrupted transaction
  (verify step skipped, run `hg verify` to check your repository content)
  $ f -s .hg/store/data/file*
  .hg/store/data/file.d: size=1046
  .hg/store/data/file.i: size=128
  $ hg tip
  changeset:   1:cfa8d6e60429
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     b
  
  $ hg verify -q
   warning: revlog 'data/file.d' not in fncache!
  1 warnings encountered!
  hint: run "hg debugrebuildfncache" to recover from corrupt fncache
  $ hg debugrebuildfncache --only-data
  adding data/file.d
  1 items added, 0 removed from fncache
  $ hg verify -q
  $ cd ..


Now retry the procedure but intercept the rename of the index and check that
the journal does not contain the new index size. This demonstrates the edge case
where the data file is left as garbage.

  $ hg clone -r 1 troffset-computation troffset-computation-copy2 --config format.revlog-compression=none -q
  $ cd troffset-computation-copy2
  $ cat > .hg/hgrc <<EOF
  > [extensions]
  > intercept_rename = $TESTTMP/intercept_rename.py
  > [hooks]
  > pretxnchangegroup = python:$TESTDIR/helper-killhook.py:killme
  > EOF
#if chg
  $ hg pull ../troffset-computation
  pulling from ../troffset-computation
  [255]
#else
  $ hg pull ../troffset-computation
  pulling from ../troffset-computation
  [80]
#endif
  $ cat .hg/store/journal | tr -s '\000' ' ' | grep data/file
  data/file.i 1174
  data/file.d 0
  data/file.d 1046

  $ hg recover
  rolling back interrupted transaction
  (verify step skipped, run `hg verify` to check your repository content)
  $ f -s .hg/store/data/file*
  .hg/store/data/file.d: size=1046
  .hg/store/data/file.i: size=1174
  $ hg tip
  changeset:   1:cfa8d6e60429
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     b
  
  $ hg verify -q
  $ cd ..


Repeat the original test but let hg rollback the transaction.

  $ hg clone -r 1 troffset-computation troffset-computation-copy-rb --config format.revlog-compression=none -q
  $ cd troffset-computation-copy-rb
  $ cat > .hg/hgrc <<EOF
  > [hooks]
  > pretxnchangegroup = false
  > EOF
  $ hg pull ../troffset-computation
  pulling from ../troffset-computation
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  transaction abort!
  rollback completed
  abort: pretxnchangegroup hook exited with status 1
  [40]
  $ f -s .hg/store/data/file*
  .hg/store/data/file.d: size=1046
  .hg/store/data/file.i: size=128
  $ hg tip
  changeset:   1:cfa8d6e60429
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     b
  
  $ hg verify -q
   warning: revlog 'data/file.d' not in fncache!
  1 warnings encountered!
  hint: run "hg debugrebuildfncache" to recover from corrupt fncache
  $ cd ..