view tests/test-sparse-clear.t @ 38893:23d582caae30

changegroup: capture revision delta in a data structure

The current changegroup generation code is tightly coupled to
the revlog API. This tight coupling makes it difficult to implement
alternate storage backends without requiring a large surface area
of the revlog API to be exposed. This is not desirable.

In order to support changegroup generation with non-revlog storage,
we'll need to abstract the concept of delta generation.

This commit is the first step down that road. We introduce a
data structure for representing a delta in a changegroup.

The API still leaves a lot to be desired. But at least we now
have separation between data and actions performed on it.

As part of this, we tweak behavior slightly: we no longer
concatenate the delta prefix with the metadata header. Instead,
we track and emit the prefix as a separate chunk. This shouldn't
have any meaningful impact since all the chunks just get sent to
the wire, the compressor, etc.

Because we're introducing a new object, this does add some
overhead to changegroup execution. `hg perfchangegroupchangelog`
on my clone of the Mercurial repo (~40,000 visible revisions in
the changelog) slows down a bit:

! wall 1.268600 comb 1.270000 user 1.270000 sys 0.000000 (best of 8)
! wall 1.419479 comb 1.410000 user 1.410000 sys 0.000000 (best of 8)

With for `hg bundle -t none-v2 -a /dev/null`:

before: real 6.610 secs (user 6.460+0.000 sys 0.140+0.000)
after:  real 7.210 secs (user 7.060+0.000 sys 0.140+0.000)

I plan to claw back this regression in future commits. And I may
even do away with this data structure once the refactor is complete.
For now, it makes things easier to comprehend.

Differential Revision: https://phab.mercurial-scm.org/D4075

test sparse

  $ hg init myrepo
  $ cd myrepo
  $ cat >> $HGRCPATH <<EOF
  > [extensions]
  > sparse=
  > purge=
  > strip=
  > rebase=
  > EOF

  $ echo a > index.html
  $ echo x > data.py
  $ echo z > readme.txt
  $ cat > base.sparse <<EOF
  > [include]
  > *.sparse
  > EOF
  $ hg ci -Aqm 'initial'
  $ cat > webpage.sparse <<EOF
  > %include base.sparse
  > [include]
  > *.html
  > EOF
  $ hg ci -Aqm 'initial'

Clear rules when there are includes

  $ hg debugsparse --include *.py
  $ ls
  data.py
  $ hg debugsparse --clear-rules
  $ ls
  base.sparse
  data.py
  index.html
  readme.txt
  webpage.sparse

Clear rules when there are excludes

  $ hg debugsparse --exclude *.sparse
  $ ls
  data.py
  index.html
  readme.txt
  $ hg debugsparse --clear-rules
  $ ls
  base.sparse
  data.py
  index.html
  readme.txt
  webpage.sparse

Clearing rules should not alter profiles

  $ hg debugsparse --enable-profile webpage.sparse
  $ ls
  base.sparse
  index.html
  webpage.sparse
  $ hg debugsparse --include *.py
  $ ls
  base.sparse
  data.py
  index.html
  webpage.sparse
  $ hg debugsparse --clear-rules
  $ ls
  base.sparse
  index.html
  webpage.sparse