view tests/test-manifestv2.t @ 27372:a79cba6cb206

help: add documentation for changegroup formats

There is no formal location for spec-like technical/internal docs. The
repository makes sense as such a location because spec-like
documentation should be reviewed (ruling out a wiki). mpm has also
stated that he would like this documentation to be part of the
built-in help system. So, we establish an "internals" sub-directory
to hold this class of documentation.

The format of changegroups does not appear to be documented anywhere,
even in source code. It therefore seemed like an appropriate first thing
to document.

This patch adds low-level documentation of versions 1 and 2 of the
changegroup foromat. It currently only describes the raw data format.
There is probably room to write higher-level documentation on strategies
for producing and consuming the data. We'll leave that for another day.

The added file is not yet accessible via `hg help` nor via hgweb.
Support for this will follow in subsequent patches.

Create repo with old manifest

  $ cat << EOF >> $HGRCPATH
  > [format]
  > usegeneraldelta=yes
  > EOF

  $ 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  delta linkrev nodeid       p1           p2
       0         0      81     -1       0 57361477c778 000000000000 000000000000
       1        81      33      0       1 aeaab5a2ef74 57361477c778 000000000000