view tests/test-pathconflicts-update.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

Path conflict checking is currently disabled by default because of issue5716.
Turn it on for this test.

  $ cat >> $HGRCPATH << EOF
  > [experimental]
  > merge.checkpathconflicts=True
  > EOF

  $ hg init repo
  $ cd repo
  $ echo base > base
  $ hg add base
  $ hg commit -m "base"
  $ hg bookmark -i base
  $ mkdir a
  $ echo 1 > a/b
  $ hg add a/b
  $ hg commit -m "file"
  $ hg bookmark -i file
  $ echo 2 > a/b
  $ hg commit -m "file2"
  $ hg bookmark -i file2
  $ hg up 0
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ mkdir a
#if symlink
  $ ln -s c a/b
#else
  $ touch a/b
#endif
  $ hg add a/b
  $ hg commit -m "link"
  created new head
  $ hg bookmark -i link
  $ hg up 0
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ mkdir -p a/b/c
  $ echo 2 > a/b/c/d
  $ hg add a/b/c/d
  $ hg commit -m "dir"
  created new head
  $ hg bookmark -i dir

Update - local file conflicts with remote directory:

  $ hg up -q 0
  $ mkdir a
  $ echo 9 > a/b
  $ hg up dir
  a/b: untracked file conflicts with directory
  abort: untracked files in working directory differ from files in requested revision
  [20]
  $ hg up dir --config merge.checkunknown=warn
  a/b: replacing untracked file
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (activating bookmark dir)
  $ cat a/b.orig
  9
  $ rm a/b.orig

Update - local symlink conflicts with remote directory:

  $ hg up -q 0
  $ mkdir a
#if symlink
  $ ln -s x a/b
#else
  $ touch a/b
#endif
  $ hg up dir
  a/b: untracked file conflicts with directory
  abort: untracked files in working directory differ from files in requested revision
  [20]
  $ hg up dir --config merge.checkunknown=warn
  a/b: replacing untracked file
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (activating bookmark dir)
#if symlink
  $ readlink.py a/b.orig
  a/b.orig -> x
#endif
  $ rm a/b.orig

Update - local directory conflicts with remote file

  $ hg up -q 0
  $ mkdir -p a/b/c
  $ echo 9 > a/b/c/d
  $ hg up file
  a/b: untracked directory conflicts with file
  abort: untracked files in working directory differ from files in requested revision
  [20]
  $ hg up file --config merge.checkunknown=warn
  a/b: replacing untracked files in directory
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (activating bookmark file)
  $ cat a/b
  1
  $ test -d a/b.orig
  $ rm -rf a/b.orig

Update - local directory conflicts with remote symlink

  $ hg up -q 0
  $ mkdir -p a/b/c
  $ echo 9 > a/b/c/d
  $ hg up link
  a/b: untracked directory conflicts with file
  abort: untracked files in working directory differ from files in requested revision
  [20]
  $ hg up link --config merge.checkunknown=warn
  a/b: replacing untracked files in directory
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (activating bookmark link)
#if symlink
  $ readlink.py a/b
  a/b -> c
#endif
  $ test -d a/b.orig
  $ rm -rf a/b.orig

Update - local renamed file conflicts with remote directory

  $ hg up -q 0
  $ hg mv base a
  $ hg status -C
  A a
    base
  R base
  $ hg up --check dir
  abort: uncommitted changes
  [20]
  $ hg up dir
  a: path conflict - a file or link has the same name as a directory
  the local file has been renamed to a~d20a80d4def3
  resolve manually then use 'hg resolve --mark a'
  1 files updated, 0 files merged, 0 files removed, 1 files unresolved
  use 'hg resolve' to retry unresolved file merges
  (activating bookmark dir)
  [1]
  $ hg status -C
  A a~d20a80d4def3
    base
  R base
  $ hg resolve --list
  P a
  $ hg up --clean -q 0

Update clean - local directory conflicts with changed remote file

  $ hg up -q file
  $ rm a/b
  $ mkdir a/b
  $ echo 9 > a/b/c
  $ hg up file2 --check --config merge.checkunknown=warn
  abort: uncommitted changes
  [20]
  $ hg up file2 --clean
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (activating bookmark file2)