view tests/test-manifestv2.t @ 26402:05871262acd5

treemanifest: rework lazy-copying code (issue4840)

The old lazy-copy code formed a chain of copied manifests with each
copy. Under typical operation, the stack never got more than a couple
of manifests deep and was fine. Under conditions like hgsubversion or
convert, the stack could get hundreds of manifests deep, and
eventually overflow the recursion limit for Python. I was able to
consistently reproduce this by converting an hgsubversion clone of
svn's history to treemanifests.

This may result in fewer manifests staying in memory during operations
like convert when treemanifests are in use, and should make those
operations faster since there will be significantly fewer noop
function calls going on.

A previous attempt (never mailed) of mine to fix this problem tried to
simply have all treemanifests only have a loadfunc - that caused
somewhat weird problems because the gettext() callable passed into
read() wasn't idempotent, so the easy solution is to have a loadfunc
and a copyfunc.

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