view tests/test-manifestv2.t @ 27430:e240e914d226 stable

revlog: seek to end of file before writing (issue4943)

Revlogs were recently refactored to open file handles in "a+" and use a
persistent file handle for reading and writing. This drastically
reduced the number of file handles being opened.

Unfortunately, it appears that some versions of Solaris lose the file
offset when performing a write after the handle has been seeked.

The simplest workaround is to seek to EOF on files opened in a+ mode
before writing to them, which is what this patch does.

Ideally, this code would exist in the vfs layer. However, this would
require creating a proxy class for file objects in order to provide a
custom implementation of write(). This would add overhead. Since
revlogs are the only files we open in a+ mode, the one-off workaround
in revlog.py should be sufficient.

This patch appears to have little to no impact on performance on my
Linux machine.

Create repo with old manifest

  $ hg init existing
  $ cd existing
  $ echo footext > foo
  $ hg add foo
  $ hg commit -m initial

We're using v1, so no manifestv2 entry is in requires yet.

  $ grep manifestv2 .hg/requires
  [1]

Let's clone this with manifestv2 enabled to switch to the new format for
future commits.

  $ cd ..
  $ hg clone --pull existing new --config experimental.manifestv2=1
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd new

Check that entry was added to .hg/requires.

  $ grep manifestv2 .hg/requires
  manifestv2

Make a new commit.

  $ echo newfootext > foo
  $ hg commit -m new

Check that the manifest actually switched to v2.

  $ hg debugdata -m 0
  foo\x0021e958b1dca695a60ee2e9cf151753204ee0f9e9 (esc)

  $ hg debugdata -m 1
  \x00 (esc)
  \x00foo\x00 (esc)
  I\xab\x7f\xb8(\x83\xcas\x15\x9d\xc2\xd3\xd3:5\x08\xbad5_ (esc)

Check that manifestv2 is used if the requirement is present, even if it's
disabled in the config.

  $ echo newerfootext > foo
  $ hg --config experimental.manifestv2=False commit -m newer

  $ hg debugdata -m 2
  \x00 (esc)
  \x00foo\x00 (esc)
  \xa6\xb1\xfb\xef]\x91\xa1\x19`\xf3.#\x90S\xf8\x06 \xe2\x19\x00 (esc)

Check that we can still read v1 manifests.

  $ hg files -r 0
  foo

  $ cd ..

Check that entry is added to .hg/requires on repo creation

  $ hg --config experimental.manifestv2=True init repo
  $ cd repo
  $ grep manifestv2 .hg/requires
  manifestv2

Set up simple repo

  $ echo a > file1
  $ echo b > file2
  $ echo c > file3
  $ hg ci -Aqm 'initial'
  $ echo d > file2
  $ hg ci -m 'modify file2'

Check that 'hg verify', which uses manifest.readdelta(), works

  $ hg verify
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  3 files, 2 changesets, 4 total revisions

Check that manifest revlog is smaller than for v1

  $ hg debugindex -m
     rev    offset  length   base linkrev nodeid       p1           p2
       0         0      81      0       0 57361477c778 000000000000 000000000000
       1        81      33      0       1 aeaab5a2ef74 57361477c778 000000000000