view tests/test-update-names.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

Test update logic when there are renames or weird same-name cases between dirs
and files

Update with local changes across a file rename

  $ hg init r1 && cd r1

  $ echo a > a
  $ hg add a
  $ hg ci -m a

  $ hg mv a b
  $ hg ci -m rename

  $ echo b > b
  $ hg ci -m change

  $ hg up -q 0

  $ echo c > a

  $ hg up
  merging a and b to b
  warning: conflicts while merging b! (edit, then use 'hg resolve --mark')
  0 files updated, 0 files merged, 0 files removed, 1 files unresolved
  use 'hg resolve' to retry unresolved file merges
  [1]

Test update when local untracked directory exists with the same name as a
tracked file in a commit we are updating to
  $ hg init r2 && cd r2
  $ echo root > root && hg ci -Am root  # rev 0
  adding root
  $ echo text > name && hg ci -Am "name is a file"  # rev 1
  adding name
  $ hg up 0
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ mkdir name
  $ hg up 1
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

Test update when local untracked directory exists with some files in it and has
the same name a tracked file in a commit we are updating to. In future this
should be updated to give an friendlier error message, but now we should just
make sure that this does not erase untracked data
  $ hg up 0
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ mkdir name
  $ echo text > name/file
  $ hg st
  ? name/file
  $ hg up 1
  abort: Unlinking directory not permitted: *$TESTTMP/r1/r2/name* (glob) (windows !)
  abort: Directory not empty: '?\$TESTTMP/r1/r2/name'? (re) (no-windows !)
  [255]
  $ cat name/file
  text
  $ cd ..

#if symlink

Test update when two commits have symlinks that point to different folders
  $ hg init r3 && cd r3
  $ echo root > root && hg ci -Am root
  adding root
  $ mkdir folder1 && mkdir folder2
  $ ln -s folder1 folder
  $ hg ci -Am "symlink to folder1"
  adding folder
  $ rm folder
  $ ln -s folder2 folder
  $ hg ci -Am "symlink to folder2"
  $ hg up 1
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd ..

#endif

#if rmcwd

Test that warning is printed if cwd is deleted during update
  $ hg init r4 && cd r4
  $ mkdir dir
  $ cd dir
  $ echo a > a
  $ echo b > b
  $ hg add a b
  $ hg ci -m "file and dir"
  $ hg up -q null
  current directory was removed
  (consider changing to repo root: $TESTTMP/r1/r4)

#endif