view tests/test-show-work.t @ 39496:2f9f7889549b

snapshot: introduce an intermediate `_refinedgroups` generator

This method will be used to improve the search for a good snapshot base. To
keep things simpler, we introduce the necessary function before doing any
delta base logic change. The next handful of commits will focus on refactoring
the code to let that new logic land as clearly as possible.

# General Idea

Right now, the search for a good delta base stop whenever we found a good one.
However, when using sparse-revlog, we should probably try a bit harder.

We do significant effort to increase delta re-use by jumping on "unrelated"
delta chains that provide better results. Moving to another chain for a better
result is good, but we have no guarantee we jump at a reasonable point in that
new chain. When we consider over the chains related to the parents, we start
from the higher-level snapshots. This is a way to consider the snapshot closer
to the current revision that has the best chance to produce a small delta. We
do benefit from this walk order when jumping to a better "unrelated" stack.

To counter-balance this, we'll introduce a way to "refine" the result. After a
good delta have been found, we'll keep searching for a better delta, using the
current best one as a starting point.

# Target Setup

The `finddeltainfo` method is responsible for the general search for a good
delta. It requests candidates base from `_candidategroups` and decides which
one are usable.

The `_candidategroups` generator act as a top-level filter, it does not care
about how we pick candidates, it just does basic filtering, excluding
revisions that have been tested already or that are an obvious misfit.

The `_rawgroups` generator is the one with the actual ancestors walking logic,
It does not care about what would do a good delta and what was already tested,
it just issues the initial candidates.

We introduce a new `_refinedgroup` function to bridge the gap between
`_candidategroups` and `_rawgroups`. It delegates the initial iteration logic
and then performing relevant refining of the valid base once found. (This
logic is yet to be added to function)

All these logics are fairly independent and easier to understand when standing
alone, not mixed with each other. It also makes it easy to test and try
different approaches for one of those four layers without affecting the other
ones.

# Technical details

To communicate `finddeltainfo` choice of "current best delta base" to the
`_refinegroup` logic, we plan to use python co-routine feature. The
`_candidategroups` and `_refinegroup` generators will become co-routine. This
will allow `_refinegroup` to detect when a good delta have been found and
triggers various refining steps.

For now, `_candidategroups` will just pass the value down the stack.

After poking at various option, the co-routine appears the best to keep each
layers focus on its duty, without the need to spread implementation details
across layers.

  $ cat >> $HGRCPATH << EOF
  > [extensions]
  > show =
  > EOF

  $ hg init repo0
  $ cd repo0

Command works on an empty repo

  $ hg show work

Single draft changeset shown

  $ echo 0 > foo
  $ hg -q commit -A -m 'commit 0'

  $ hg show work
  @  9f17 commit 0

Even when it isn't the wdir

  $ hg -q up null

  $ hg show work
  o  9f17 commit 0

Single changeset is still there when public because it is a head

  $ hg phase --public -r 0
  $ hg show work
  o  9f17 commit 0

A draft child will show both it and public parent

  $ hg -q up 0
  $ echo 1 > foo
  $ hg commit -m 'commit 1'

  $ hg show work
  @  181c commit 1
  o  9f17 commit 0

Multiple draft children will be shown

  $ echo 2 > foo
  $ hg commit -m 'commit 2'

  $ hg show work
  @  128c commit 2
  o  181c commit 1
  o  9f17 commit 0

Bumping first draft changeset to public will hide its parent

  $ hg phase --public -r 1
  $ hg show work
  @  128c commit 2
  o  181c commit 1
  ~

Multiple DAG heads will be shown

  $ hg -q up -r 1
  $ echo 3 > foo
  $ hg commit -m 'commit 3'
  created new head

  $ hg show work
  @  f0ab commit 3
  | o  128c commit 2
  |/
  o  181c commit 1
  ~

Even when wdir is something else

  $ hg -q up null

  $ hg show work
  o  f0ab commit 3
  | o  128c commit 2
  |/
  o  181c commit 1
  ~

Draft child shows public head (multiple heads)

  $ hg -q up 0
  $ echo 4 > foo
  $ hg commit -m 'commit 4'
  created new head

  $ hg show work
  @  668c commit 4
  | o  f0ab commit 3
  | | o  128c commit 2
  | |/
  | o  181c commit 1
  |/
  o  9f17 commit 0

  $ cd ..

Branch name appears in output

  $ hg init branches
  $ cd branches
  $ echo 0 > foo
  $ hg -q commit -A -m 'commit 0'
  $ echo 1 > foo
  $ hg commit -m 'commit 1'
  $ echo 2 > foo
  $ hg commit -m 'commit 2'
  $ hg phase --public -r .
  $ hg -q up -r 1
  $ hg branch mybranch
  marked working directory as branch mybranch
  (branches are permanent and global, did you want a bookmark?)
  $ echo 3 > foo
  $ hg commit -m 'commit 3'
  $ echo 4 > foo
  $ hg commit -m 'commit 4'

  $ hg show work
  @  f8dd (mybranch) commit 4
  o  90cf (mybranch) commit 3
  | o  128c commit 2
  |/
  o  181c commit 1
  ~

  $ cd ..

Bookmark name appears in output

  $ hg init bookmarks
  $ cd bookmarks
  $ echo 0 > foo
  $ hg -q commit -A -m 'commit 0'
  $ echo 1 > foo
  $ hg commit -m 'commit 1'
  $ echo 2 > foo
  $ hg commit -m 'commit 2'
  $ hg phase --public -r .
  $ hg bookmark @
  $ hg -q up -r 1
  $ echo 3 > foo
  $ hg commit -m 'commit 3'
  created new head
  $ echo 4 > foo
  $ hg commit -m 'commit 4'
  $ hg bookmark mybook

  $ hg show work
  @  cac8 (mybook) commit 4
  o  f0ab commit 3
  | o  128c (@) commit 2
  |/
  o  181c commit 1
  ~

  $ cd ..

Tags are rendered

  $ hg init tags
  $ cd tags
  $ echo 0 > foo
  $ hg -q commit -A -m 'commit 1'
  $ echo 1 > foo
  $ hg commit -m 'commit 2'
  $ hg tag 0.1
  $ hg phase --public -r .
  $ echo 2 > foo
  $ hg commit -m 'commit 3'
  $ hg tag 0.2

  $ hg show work
  @  3758 Added tag 0.2 for changeset 6379c25b76f1
  o  6379 (0.2) commit 3
  o  a2ad Added tag 0.1 for changeset 6a75536ea0b1
  ~

  $ cd ..

Multiple names on same changeset render properly

  $ hg init multiplenames
  $ cd multiplenames
  $ echo 0 > foo
  $ hg -q commit -A -m 'commit 1'
  $ hg phase --public -r .
  $ hg branch mybranch
  marked working directory as branch mybranch
  (branches are permanent and global, did you want a bookmark?)
  $ hg bookmark mybook
  $ echo 1 > foo
  $ hg commit -m 'commit 2'

  $ hg show work
  @  3483 (mybook) (mybranch) commit 2
  o  97fc commit 1

Multiple bookmarks on same changeset render properly

  $ hg book mybook2
  $ hg show work
  @  3483 (mybook mybook2) (mybranch) commit 2
  o  97fc commit 1

  $ cd ..

Extra namespaces are rendered

  $ hg init extranamespaces
  $ cd extranamespaces
  $ echo 0 > foo
  $ hg -q commit -A -m 'commit 1'
  $ hg phase --public -r .
  $ echo 1 > foo
  $ hg commit -m 'commit 2'
  $ echo 2 > foo
  $ hg commit -m 'commit 3'

  $ hg --config extensions.revnames=$TESTDIR/revnamesext.py show work
  @  32f3 (r2) commit 3
  o  6a75 (r1) commit 2
  o  97fc (r0) commit 1

Obsolescence information appears in labels.

  $ cat >> .hg/hgrc << EOF
  > [experimental]
  > evolution=createmarkers
  > EOF
  $ hg debugobsolete `hg log -r 'desc("commit 2")' -T "{node}"`
  obsoleted 1 changesets
  1 new orphan changesets
  $ hg show work --color=debug
  @  [log.changeset changeset.draft changeset.unstable instability.orphan|32f3] [log.description|commit 3]
  x  [log.changeset changeset.draft changeset.obsolete|6a75] [log.description|commit 2]
  ~

  $ cd ..

Prefix collision on hashes increases shortest node length

  $ hg init hashcollision
  $ cd hashcollision
  $ echo 0 > a
  $ hg -q commit -Am 0
  $ for i in 17 1057 2857 4025; do
  >   hg -q up 0
  >   echo $i > a
  >   hg -q commit -m $i
  >   echo 0 > a
  >   hg commit -m "$i commit 2"
  > done

  $ hg show work
  @  cfd04 4025 commit 2
  o  c562d 4025
  | o  08048 2857 commit 2
  | o  c5623 2857
  |/
  | o  6a6b6 1057 commit 2
  | o  c5625 1057
  |/
  | o  96b4e 17 commit 2
  | o  11424 17
  |/
  o  b4e73 0

  $ cd ..