tests/test-exchange-obsmarkers-case-B5.t

rhg: Port Python’s `ui.configlist` as `Config::get_list`

This new method is not used yet outside of its own unit tests,
so this changeset should make no observable change.

The Rust parser implementation attempts to exactly replicate the behavior of
the Python one, even in edge cases where that behavior is… surprising.
New unit tests capture some of these edge cases.

This started as a line-by-line port. The main changes are:

* Pass around a parser mode enum instead of parser functions
* Inline the whole parser into one function
* Use `[u8]::get` which returns an `Option`,
  instead of indexing  after explicitly checking the length.

Differential Revision: https://phab.mercurial-scm.org/D11389

============================================
Testing obsolescence markers push: Cases B.5
============================================

Mercurial pushes obsolescences markers relevant to the "pushed-set", the set of
all changesets that requested to be "in sync" after the push (even if they are
already on both side).

This test belongs to a series of tests checking such set is properly computed
and applied. This does not tests "obsmarkers" discovery capabilities.

Category B: pruning case
TestCase 5: Push of a children of changeset which successors is pruned

B.5 Push of a children of changeset which successors is pruned
==============================================================

.. This case Mirror A.4, with pruned changeset successors.
..
.. {{{
..   C ◔
..     |
..   B⇠ø⇠⊗ B'
..     | |
..   A ø⇠○ A'
..     |/
..     ●
.. }}}
..
.. Marker exist from:
..
..  * `A ø⇠○ A'`
..  * `B ø⇠○ B'`
..  * chain from B
..  * `B' is pruned`
..
.. Command run:
..
..  * hg push -r C
..
.. Expected exchange:
..
..  * chain from B
..
.. Expected exclude:
..
..  * `A ø⇠○ A'`
..  * `B ø⇠○ B'`
..  * `B' prune`

Setup
-----

  $ . $TESTDIR/testlib/exchange-obsmarker-util.sh

initial

  $ setuprepos B.5
  creating test repo for test case B.5
  - pulldest
  - main
  - pushdest
  cd into `main` and proceed with env setup
  $ cd main
  $ mkcommit A0
  $ mkcommit B0
  $ mkcommit C
  $ hg up --quiet 0
  $ mkcommit A1
  created new head
  $ mkcommit B1
  $ hg debugobsolete --hidden `getid 'desc(A0)'` `getid 'desc(A1)'`
  1 new obsolescence markers
  obsoleted 1 changesets
  2 new orphan changesets
  $ hg debugobsolete --hidden aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa `getid 'desc(B0)'`
  1 new obsolescence markers
  $ hg debugobsolete --hidden `getid 'desc(B0)'` `getid 'desc(B1)'`
  1 new obsolescence markers
  obsoleted 1 changesets
  $ hg prune -qd '0 0' 'desc(B1)'
  $ hg log -G --hidden
  x  069b05c3876d (draft): B1
  |
  @  e5ea8f9c7314 (draft): A1
  |
  | *  1d0f3cd25300 (draft): C
  | |
  | x  6e72f0a95b5e (draft): B0
  | |
  | x  28b51eb45704 (draft): A0
  |/
  o  a9bdc8b26820 (public): O
  
  $ inspect_obsmarkers
  obsstore content
  ================
  28b51eb45704506b5c603decd6bf7ac5e0f6a52f e5ea8f9c73143125d36658e90ef70c6d2027a5b7 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
  aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa 6e72f0a95b5e01a7504743aa941f69cb1fbef8b0 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
  6e72f0a95b5e01a7504743aa941f69cb1fbef8b0 069b05c3876d56f62895e853a501ea58ea85f68d 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
  069b05c3876d56f62895e853a501ea58ea85f68d 0 {e5ea8f9c73143125d36658e90ef70c6d2027a5b7} (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
  $ cd ..
  $ cd ..

Actual Test (explicit push version)
-----------------------------------

  $ dotest B.5 C -f
  ## Running testcase B.5
  # testing echange of "C" (1d0f3cd25300)
  ## initial state
  # obstore: main
  069b05c3876d56f62895e853a501ea58ea85f68d 0 {e5ea8f9c73143125d36658e90ef70c6d2027a5b7} (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
  28b51eb45704506b5c603decd6bf7ac5e0f6a52f e5ea8f9c73143125d36658e90ef70c6d2027a5b7 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
  6e72f0a95b5e01a7504743aa941f69cb1fbef8b0 069b05c3876d56f62895e853a501ea58ea85f68d 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
  aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa 6e72f0a95b5e01a7504743aa941f69cb1fbef8b0 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
  # obstore: pushdest
  # obstore: pulldest
  ## pushing "C" from main to pushdest
  pushing to pushdest
  searching for changes
  remote: adding changesets
  remote: adding manifests
  remote: adding file changes
  remote: added 3 changesets with 3 changes to 3 files
  remote: 1 new obsolescence markers
  ## post push state
  # obstore: main
  069b05c3876d56f62895e853a501ea58ea85f68d 0 {e5ea8f9c73143125d36658e90ef70c6d2027a5b7} (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
  28b51eb45704506b5c603decd6bf7ac5e0f6a52f e5ea8f9c73143125d36658e90ef70c6d2027a5b7 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
  6e72f0a95b5e01a7504743aa941f69cb1fbef8b0 069b05c3876d56f62895e853a501ea58ea85f68d 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
  aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa 6e72f0a95b5e01a7504743aa941f69cb1fbef8b0 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
  # obstore: pushdest
  aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa 6e72f0a95b5e01a7504743aa941f69cb1fbef8b0 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
  # obstore: pulldest
  ## pulling "1d0f3cd25300" from main into pulldest
  pulling from main
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 3 changesets with 3 changes to 3 files
  1 new obsolescence markers
  new changesets 28b51eb45704:1d0f3cd25300 (3 drafts)
  (run 'hg update' to get a working copy)
  ## post pull state
  # obstore: main
  069b05c3876d56f62895e853a501ea58ea85f68d 0 {e5ea8f9c73143125d36658e90ef70c6d2027a5b7} (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
  28b51eb45704506b5c603decd6bf7ac5e0f6a52f e5ea8f9c73143125d36658e90ef70c6d2027a5b7 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
  6e72f0a95b5e01a7504743aa941f69cb1fbef8b0 069b05c3876d56f62895e853a501ea58ea85f68d 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
  aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa 6e72f0a95b5e01a7504743aa941f69cb1fbef8b0 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
  # obstore: pushdest
  aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa 6e72f0a95b5e01a7504743aa941f69cb1fbef8b0 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
  # obstore: pulldest
  aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa 6e72f0a95b5e01a7504743aa941f69cb1fbef8b0 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}