view tests/test-sparse-merges.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 merging things outside of the sparse checkout

  $ hg init myrepo
  $ cd myrepo
  $ cat > .hg/hgrc <<EOF
  > [extensions]
  > sparse=
  > EOF

  $ echo foo > foo
  $ echo bar > bar
  $ hg add foo bar
  $ hg commit -m initial

  $ hg branch feature
  marked working directory as branch feature
  (branches are permanent and global, did you want a bookmark?)
  $ echo bar2 >> bar
  $ hg commit -m 'feature - bar2'

  $ hg update -q default
  $ hg debugsparse --exclude 'bar**'

  $ hg merge feature
  temporarily included 1 file(s) in the sparse checkout for merging
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)

Verify bar was merged temporarily

  $ ls -A
  .hg
  bar
  foo
  $ hg status
  M bar

Verify bar disappears automatically when the working copy becomes clean

  $ hg commit -m "merged"
  cleaned up 1 temporarily added file(s) from the sparse checkout
  $ hg status
  $ ls -A
  .hg
  foo

  $ hg cat -r . bar
  bar
  bar2

Test merging things outside of the sparse checkout that are not in the working
copy

  $ hg strip -q -r . --config extensions.strip=
  $ hg up -q feature
  $ touch branchonly
  $ hg ci -Aqm 'add branchonly'

  $ hg up -q default
  $ hg debugsparse -X branchonly
  $ hg merge feature
  temporarily included 2 file(s) in the sparse checkout for merging
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)

  $ cd ..

Tests merging a file which is modified in one branch and deleted in another and
file is excluded from sparse checkout

  $ hg init ytest
  $ cd ytest
  $ echo "syntax: glob" >> .hgignore
  $ echo "*.orig" >> .hgignore
  $ hg ci -Aqm "added .hgignore"
  $ for ch in a d; do echo foo > $ch; hg ci -Aqm "added "$ch; done;
  $ cat >> .hg/hgrc <<EOF
  > [alias]
  > glog = log -GT "{rev}:{node|short} {desc}"
  > [extensions]
  > sparse =
  > EOF

  $ hg glog
  @  2:f29feff37cfc added d
  |
  o  1:617125d27d6b added a
  |
  o  0:53f3774ed939 added .hgignore
  
  $ hg rm d
  $ hg ci -m "removed d"

  $ hg up '.^'
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg debugsparse --reset
  $ echo bar >> d
  $ hg ci -Am "added bar to d"
  created new head

  $ hg glog
  @  4:6527874a90e4 added bar to d
  |
  | o  3:372c8558de45 removed d
  |/
  o  2:f29feff37cfc added d
  |
  o  1:617125d27d6b added a
  |
  o  0:53f3774ed939 added .hgignore
  
  $ hg debugsparse --exclude "d"
  $ ls -A
  .hg
  .hgignore
  a

  $ hg merge
  temporarily included 1 file(s) in the sparse checkout for merging
  file 'd' was deleted in other [merge rev] but was modified in local [working copy].
  You can use (c)hanged version, (d)elete, or leave (u)nresolved.
  What do you want to do? u
  0 files updated, 0 files merged, 0 files removed, 1 files unresolved
  use 'hg resolve' to retry unresolved file merges or 'hg merge --abort' to abandon
  [1]

  $ cd ..

Testing merging of a file which is renamed+modified on one side and modified on
another

  $ hg init mvtest
  $ cd mvtest
  $ echo "syntax: glob" >> .hgignore
  $ echo "*.orig" >> .hgignore
  $ hg ci -Aqm "added .hgignore"
  $ for ch in a d; do echo foo > $ch; hg ci -Aqm "added "$ch; done;
  $ cat >> .hg/hgrc <<EOF
  > [alias]
  > glog = log -GT "{rev}:{node|short} {desc}"
  > [extensions]
  > sparse =
  > EOF

  $ hg glog
  @  2:f29feff37cfc added d
  |
  o  1:617125d27d6b added a
  |
  o  0:53f3774ed939 added .hgignore
  
  $ echo babar >> a
  $ hg ci -m "added babar to a"

  $ hg up '.^'
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg mv a amove
  $ hg ci -m "moved a to amove"
  created new head

  $ hg up 3
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ hg glog
  o  4:5d1e85955f6d moved a to amove
  |
  | @  3:a06e41a6c16c added babar to a
  |/
  o  2:f29feff37cfc added d
  |
  o  1:617125d27d6b added a
  |
  o  0:53f3774ed939 added .hgignore
  
  $ hg debugsparse --exclude "a"
  $ ls -A
  .hg
  .hgignore
  d

  $ hg merge
  temporarily included 1 file(s) in the sparse checkout for merging
  merging a and amove to amove
  0 files updated, 1 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)

  $ hg up -C 4
  cleaned up 1 temporarily added file(s) from the sparse checkout
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

  $ hg merge
  merging amove and a to amove
  abort: cannot add 'a' - it is outside the sparse checkout
  (include file with `hg debugsparse --include <pattern>` or use `hg add -s <file>` to include file directory while adding)
  [255]