view tests/test-convert-bzr-directories.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

#require bzr

  $ . "$TESTDIR/bzr-definitions"

Work around https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=944379
  $ mkdir -p "${HOME}/.config/breezy"

empty directory

  $ mkdir test-empty
  $ cd test-empty
  $ brz init -q source
  $ cd source
  $ echo content > a
  $ brz add -q a
  $ brz commit -q -m 'Initial add'
  $ mkdir empty
  $ brz add -q empty
  $ brz commit -q -m 'Empty directory added'
  $ echo content > empty/something
  $ brz add -q empty/something
  $ brz commit -q -m 'Added file into directory'
  $ cd ..
  $ hg convert source source-hg
  initializing destination source-hg repository
  scanning source...
  sorting...
  converting...
  2 Initial add
  1 Empty directory added
  0 Added file into directory
  $ manifest source-hg 1
  % manifest of 1
  644   a
  $ manifest source-hg tip
  % manifest of tip
  644   a
  644   empty/something
  $ cd ..

directory renames

  $ mkdir test-dir-rename
  $ cd test-dir-rename
  $ brz init -q source
  $ cd source
  $ mkdir tpyo
  $ echo content > tpyo/something
  $ brz add -q tpyo
  $ brz commit -q -m 'Added directory'
  $ brz mv tpyo typo
  tpyo => typo
  $ brz commit -q -m 'Oops, typo'
  $ cd ..
  $ hg convert source source-hg
  initializing destination source-hg repository
  scanning source...
  sorting...
  converting...
  1 Added directory
  0 Oops, typo
  $ manifest source-hg 0
  % manifest of 0
  644   tpyo/something
  $ manifest source-hg tip
  % manifest of tip
  644   typo/something
  $ cd ..

nested directory renames

  $ mkdir test-nested-dir-rename
  $ cd test-nested-dir-rename
  $ brz init -q source
  $ cd source
  $ mkdir -p firstlevel/secondlevel/thirdlevel
  $ echo content > firstlevel/secondlevel/file
  $ echo this_needs_to_be_there_too > firstlevel/secondlevel/thirdlevel/stuff
  $ brz add -q firstlevel
  $ brz commit -q -m 'Added nested directories'
  $ brz mv firstlevel/secondlevel secondlevel
  firstlevel/secondlevel => secondlevel
  $ brz commit -q -m 'Moved secondlevel one level up'
  $ cd ..
  $ hg convert source source-hg
  initializing destination source-hg repository
  scanning source...
  sorting...
  converting...
  1 Added nested directories
  0 Moved secondlevel one level up
  $ manifest source-hg tip
  % manifest of tip
  644   secondlevel/file
  644   secondlevel/thirdlevel/stuff
  $ cd ..

directory remove

  $ mkdir test-dir-remove
  $ cd test-dir-remove
  $ brz init -q source
  $ cd source
  $ mkdir src
  $ echo content > src/sourcecode
  $ brz add -q src
  $ brz commit -q -m 'Added directory'
  $ brz rm -q src
  $ brz commit -q -m 'Removed directory'
  $ cd ..
  $ hg convert source source-hg
  initializing destination source-hg repository
  scanning source...
  sorting...
  converting...
  1 Added directory
  0 Removed directory
  $ manifest source-hg 0
  % manifest of 0
  644   src/sourcecode
  $ manifest source-hg tip
  % manifest of tip
  $ cd ..

directory replace

  $ mkdir test-dir-replace
  $ cd test-dir-replace
  $ brz init -q source
  $ cd source
  $ mkdir first second
  $ echo content > first/file
  $ echo morecontent > first/dummy
  $ echo othercontent > second/something
  $ brz add -q first second
  $ brz commit -q -m 'Initial layout'
  $ brz mv first/file second/file
  first/file => second/file
  $ brz mv first third
  first => third
  $ brz commit -q -m 'Some conflicting moves'
  $ cd ..
  $ hg convert source source-hg
  initializing destination source-hg repository
  scanning source...
  sorting...
  converting...
  1 Initial layout
  0 Some conflicting moves
  $ manifest source-hg tip
  % manifest of tip
  644   second/file
  644   second/something
  644   third/dummy
  $ cd ..

divergent nested renames (issue3089)

  $ mkdir test-divergent-renames
  $ cd test-divergent-renames
  $ brz init -q source
  $ cd source
  $ mkdir -p a/c
  $ echo a > a/fa
  $ echo c > a/c/fc
  $ brz add -q a
  $ brz commit -q -m 'Initial layout'
  $ brz mv a b
  a => b
  $ mkdir a
  $ brz add a
  add(ed|ing) a (re)
  $ brz mv b/c a/c
  b/c => a/c
  $ brz status
  added:
    a/
  renamed:
    a/? => b/? (re)
    a/c/? => a/c/? (re)
  $ brz commit -q -m 'Divergent renames'
  $ cd ..
  $ hg convert source source-hg
  initializing destination source-hg repository
  scanning source...
  sorting...
  converting...
  1 Initial layout
  0 Divergent renames
  $ hg -R source-hg st -C --change 1
  A b/fa
    a/fa
  R a/fa
  $ hg -R source-hg manifest -r 1
  a/c/fc
  b/fa
  $ cd ..