view tests/test-obsolete-checkheads.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

Check that obsolete properly strip heads
  $ cat >> $HGRCPATH << EOF
  > [phases]
  > # public changeset are not obsolete
  > publish=false
  > [command-templates]
  > log='{node|short} ({phase}) {desc|firstline}\n'
  > [experimental]
  > evolution.createmarkers=True
  > EOF
  $ mkcommit() {
  >    echo "$1" > "$1"
  >    hg add "$1"
  >    hg ci -m "add $1"
  > }
  $ getid() {
  >    hg id --debug -ir "desc('$1')"
  > }


  $ hg init remote
  $ cd remote
  $ mkcommit base
  $ hg phase --public .
  $ cd ..
  $ cp -R remote base
  $ hg clone remote local
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd local

New head replaces old head
==========================

setup
(we add the 1 flags to prevent bumped error during the test)

  $ mkcommit old
  $ hg push
  pushing to $TESTTMP/remote
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files
  $ hg up -q '.^'
  $ mkcommit new
  created new head
  $ hg debugobsolete --flags 1 `getid old` `getid new`
  1 new obsolescence markers
  obsoleted 1 changesets
  $ hg log -G --hidden
  @  71e3228bffe1 (draft) add new
  |
  | x  c70b08862e08 (draft) add old
  |/
  o  b4952fcf48cf (public) add base
  
  $ cp -R ../remote ../backup1

old exists remotely as draft. It is obsoleted by new that we now push.
Push should not warn about creating new head

  $ hg push
  pushing to $TESTTMP/remote
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files (+1 heads)

old head is now public (public local version)
=============================================

setup

  $ rm -fr ../remote
  $ cp -R ../backup1 ../remote
  $ hg -R ../remote phase --public c70b08862e08
  $ hg pull -v
  pulling from $TESTTMP/remote
  searching for changes
  no changes found
  1 local changesets published
  $ hg log -G --hidden
  @  71e3228bffe1 (draft) add new
  |
  | o  c70b08862e08 (public) add old
  |/
  o  b4952fcf48cf (public) add base
  

Abort: old will still be an head because it's public.

  $ hg push
  pushing to $TESTTMP/remote
  searching for changes
  abort: push creates new remote head 71e3228bffe1
  (merge or see 'hg help push' for details about pushing new heads)
  [20]

old head is now public (public remote version)
==============================================

TODO: Not implemented yet.

# setup
#
#   $ rm -fr ../remote
#   $ cp -R ../backup1 ../remote
#   $ hg -R ../remote phase --public c70b08862e08
#   $ hg phase --draft --force c70b08862e08
#   $ hg log -G --hidden
#   @  71e3228bffe1 (draft) add new
#   |
#   | x  c70b08862e08 (draft) add old
#   |/
#   o  b4952fcf48cf (public) add base
#
#
#
# Abort: old will still be an head because it's public.
#
#   $ hg push
#   pushing to $TESTTMP/remote
#   searching for changes
#   abort: push creates new remote head 71e3228bffe1!
#   (merge or see 'hg help push' for details about pushing new heads)
#   [255]

old head is obsolete but replacement is not pushed
==================================================

setup

  $ rm -fr ../remote
  $ cp -R ../backup1 ../remote
  $ hg phase --draft --force '(0::) - 0'
  $ hg up -q '.^'
  $ mkcommit other
  created new head
  $ hg log -G --hidden
  @  d7d41ccbd4de (draft) add other
  |
  | o  71e3228bffe1 (draft) add new
  |/
  | x  c70b08862e08 (draft) add old
  |/
  o  b4952fcf48cf (public) add base
  

old exists remotely as draft. It is obsoleted by new but we don't push new.
Push should abort on new head

  $ hg push -r 'desc("other")'
  pushing to $TESTTMP/remote
  searching for changes
  abort: push creates new remote head d7d41ccbd4de
  (merge or see 'hg help push' for details about pushing new heads)
  [20]



Both precursors and successors are already know remotely. Descendant adds heads
===============================================================================

setup. (The obsolete marker is known locally only

  $ cd ..
  $ rm -rf local
  $ hg clone remote local
  updating to branch default
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd local
  $ mkcommit old
  old already tracked!
  nothing changed
  [1]
  $ hg up -q '.^'
  $ mkcommit new
  created new head
  $ hg push -f
  pushing to $TESTTMP/remote
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files (+1 heads)
  $ mkcommit desc1
  $ hg up -q '.^'
  $ mkcommit desc2
  created new head
  $ hg debugobsolete `getid old` `getid new`
  1 new obsolescence markers
  obsoleted 1 changesets
  $ hg log -G --hidden
  @  5fe37041cc2b (draft) add desc2
  |
  | o  a3ef1d111c5f (draft) add desc1
  |/
  o  71e3228bffe1 (draft) add new
  |
  | x  c70b08862e08 (draft) add old
  |/
  o  b4952fcf48cf (public) add base
  
  $ hg log -G --hidden -R ../remote
  o  71e3228bffe1 (draft) add new
  |
  | o  c70b08862e08 (draft) add old
  |/
  @  b4952fcf48cf (public) add base
  
  $ cp -R ../remote ../backup2

Push should not warn about adding new heads. We create one, but we'll delete
one anyway.

  $ hg push
  pushing to $TESTTMP/remote
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 2 changesets with 2 changes to 2 files (+1 heads)


Remote head is unknown but obsoleted by a local changeset
=========================================================

setup

  $ rm -fr ../remote
  $ cp -R ../backup1 ../remote
  $ cd ..
  $ rm -rf local
  $ hg clone remote local -r 0
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files
  new changesets b4952fcf48cf
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd local
  $ mkcommit new
  $ hg -R ../remote id --debug -r tip
  c70b08862e0838ea6d7c59c85da2f1ed6c8d67da tip
  $ hg  id --debug -r tip
  71e3228bffe1886550777233d6c97bb5a6b2a650 tip
  $ hg debugobsolete c70b08862e0838ea6d7c59c85da2f1ed6c8d67da 71e3228bffe1886550777233d6c97bb5a6b2a650
  1 new obsolescence markers
  $ hg log -G --hidden
  @  71e3228bffe1 (draft) add new
  |
  o  b4952fcf48cf (public) add base
  
  $ hg log -G --hidden -R ../remote
  o  c70b08862e08 (draft) add old
  |
  @  b4952fcf48cf (public) add base
  

We do not have enought data to take the right decision, we should fail

  $ hg push
  pushing to $TESTTMP/remote
  searching for changes
  remote has heads on branch 'default' that are not known locally: c70b08862e08
  abort: push creates new remote head 71e3228bffe1
  (pull and merge or see 'hg help push' for details about pushing new heads)
  [20]

Pulling the missing data makes it work

  $ hg pull
  pulling from $TESTTMP/remote
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files (+1 heads)
  (1 other changesets obsolete on arrival)
  (run 'hg heads' to see heads)
  $ hg push
  pushing to $TESTTMP/remote
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files (+1 heads)

Old head is pruned without parent data and new unrelated head added
===================================================================

setup

  $ cd ..
  $ rm -R remote local
  $ cp -R backup1 remote
  $ hg clone remote local -qr c70b08862e08
  $ cd local
  $ hg up -q '.^'
  $ mkcommit new-unrelated
  created new head
  $ hg debugobsolete `getid old`
  1 new obsolescence markers
  obsoleted 1 changesets
  $ hg log -G --hidden
  @  350a93b716be (draft) add new-unrelated
  |
  | x  c70b08862e08 (draft) add old
  |/
  o  b4952fcf48cf (public) add base
  

  $ hg push
  pushing to $TESTTMP/remote
  searching for changes
  abort: push creates new remote head 350a93b716be
  (merge or see 'hg help push' for details about pushing new heads)
  [20]