view tests/test-exchange-obsmarkers-case-D4.t @ 49000:dd6b67d5c256 stable

rust: fix unsound `OwningDirstateMap`

As per the previous patch, `OwningDirstateMap` is unsound. Self-referential
structs are difficult to implement correctly in Rust since the compiler is
free to move structs around as much as it wants to. They are also very rarely
needed in practice, so the state-of-the-art on how they should be done within
the Rust rules is still a bit new.

The crate `ouroboros` is an attempt at providing a safe way (in the Rust sense)
of declaring self-referential structs. It is getting a lot attention and was
improved very quickly when soundness issues were found in the past: rather than
relying on our own (limited) review circle, we might as well use the de-facto
common crate to fix this problem. This will give us a much better chance of
finding issues should any new ones be discovered as well as the benefit of
fewer `unsafe` APIs of our own.

I was starting to think about how I would present a safe API to the old struct
but soon realized that the callback-based approach was already done in
`ouroboros`, along with a lot more care towards refusing incorrect structs.

In short: we don't return a mutable reference to the `DirstateMap` anymore, we
expect users of its API to pass a `FnOnce` that takes the map as an argument.
This allows our `OwningDirstateMap` to control the input and output lifetimes
of the code that modifies it to prevent such issues.

Changing to `ouroboros` meant changing every API with it, but it is relatively
low churn in the end. It correctly identified the example buggy modification of
`copy_map_insert` outlined in the previous patch as violating the borrow rules.

Differential Revision: https://phab.mercurial-scm.org/D12429

============================================
Testing obsolescence markers push: Cases D.4
============================================

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 D: Partial Information Case
TestCase 4: Unknown changeset in between known changesets

D.4 Unknown changeset in between known one
==========================================

.. Mostly a clarification case
..
.. {{{
..   B ø⇠◌⇠○ B''
..     |   |
..   A ø⇠◌⇠◔ A'
..      \ /
..       ● O
..
.. }}}
..
.. Should be treated as A.3 case:
..
.. {{{
..
..   B ø⇠○ B''
..     | |
..   A ø⇠◔ A'
..     |/
..     ● O
..
.. }}}

Setup
-----

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

initial

  $ setuprepos D.4
  creating test repo for test case D.4
  - pulldest
  - main
  - pushdest
  cd into `main` and proceed with env setup
  $ cd main
  $ mkcommit A0
  $ mkcommit B0
  $ hg update -q 0
  $ mkcommit A1
  created new head
  $ mkcommit B1
  $ hg debugobsolete `getid 'desc(A0)'` aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
  1 new obsolescence markers
  obsoleted 1 changesets
  1 new orphan changesets
  $ hg debugobsolete aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa `getid 'desc(A1)'`
  1 new obsolescence markers
  $ hg debugobsolete `getid 'desc(B0)'` bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
  1 new obsolescence markers
  obsoleted 1 changesets
  $ hg debugobsolete bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb `getid 'desc(B1)'`
  1 new obsolescence markers
  $ hg log -G --hidden
  @  069b05c3876d (draft): B1
  |
  o  e5ea8f9c7314 (draft): A1
  |
  | x  6e72f0a95b5e (draft): B0
  | |
  | x  28b51eb45704 (draft): A0
  |/
  o  a9bdc8b26820 (public): O
  
  $ inspect_obsmarkers
  obsstore content
  ================
  28b51eb45704506b5c603decd6bf7ac5e0f6a52f aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
  aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa e5ea8f9c73143125d36658e90ef70c6d2027a5b7 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
  6e72f0a95b5e01a7504743aa941f69cb1fbef8b0 bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
  bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb 069b05c3876d56f62895e853a501ea58ea85f68d 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
  $ cd ..
  $ cd ..

Actual Test
-----------

  $ dotest D.4 A1
  ## Running testcase D.4
  # testing echange of "A1" (e5ea8f9c7314)
  ## initial state
  # obstore: main
  28b51eb45704506b5c603decd6bf7ac5e0f6a52f aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
  6e72f0a95b5e01a7504743aa941f69cb1fbef8b0 bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
  aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa e5ea8f9c73143125d36658e90ef70c6d2027a5b7 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
  bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb 069b05c3876d56f62895e853a501ea58ea85f68d 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
  # obstore: pushdest
  # obstore: pulldest
  ## pushing "A1" from main to pushdest
  pushing to pushdest
  searching for changes
  remote: adding changesets
  remote: adding manifests
  remote: adding file changes
  remote: added 1 changesets with 1 changes to 1 files
  remote: 2 new obsolescence markers
  ## post push state
  # obstore: main
  28b51eb45704506b5c603decd6bf7ac5e0f6a52f aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
  6e72f0a95b5e01a7504743aa941f69cb1fbef8b0 bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
  aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa e5ea8f9c73143125d36658e90ef70c6d2027a5b7 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
  bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb 069b05c3876d56f62895e853a501ea58ea85f68d 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
  # obstore: pushdest
  28b51eb45704506b5c603decd6bf7ac5e0f6a52f aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
  aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa e5ea8f9c73143125d36658e90ef70c6d2027a5b7 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
  # obstore: pulldest
  ## pulling "e5ea8f9c7314" from main into pulldest
  pulling from main
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files
  2 new obsolescence markers
  new changesets e5ea8f9c7314 (1 drafts)
  (run 'hg update' to get a working copy)
  ## post pull state
  # obstore: main
  28b51eb45704506b5c603decd6bf7ac5e0f6a52f aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
  6e72f0a95b5e01a7504743aa941f69cb1fbef8b0 bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
  aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa e5ea8f9c73143125d36658e90ef70c6d2027a5b7 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
  bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb 069b05c3876d56f62895e853a501ea58ea85f68d 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
  # obstore: pushdest
  28b51eb45704506b5c603decd6bf7ac5e0f6a52f aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
  aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa e5ea8f9c73143125d36658e90ef70c6d2027a5b7 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
  # obstore: pulldest
  28b51eb45704506b5c603decd6bf7ac5e0f6a52f aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
  aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa e5ea8f9c73143125d36658e90ef70c6d2027a5b7 0 (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}