view tests/test-remotefilelog-log.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 no-windows

  $ . "$TESTDIR/remotefilelog-library.sh"

  $ hg init master
  $ cd master
  $ cat >> .hg/hgrc <<EOF
  > [remotefilelog]
  > server=True
  > EOF
  $ echo x > x
  $ hg commit -qAm x
  $ mkdir dir
  $ echo y > dir/y
  $ hg commit -qAm y

  $ cd ..

Shallow clone from full

  $ hgcloneshallow ssh://user@dummy/master shallow --noupdate
  streaming all changes
  2 files to transfer, 473 bytes of data
  transferred 473 bytes in * seconds (*/sec) (glob)
  searching for changes
  no changes found
  $ cd shallow
  $ hg debugrequires
  dotencode
  dirstate-v2 (dirstate-v2 !)
  exp-remotefilelog-repo-req-1
  fncache
  generaldelta
  persistent-nodemap (rust !)
  revlog-compression-zstd (zstd !)
  revlogv1
  share-safe
  sparserevlog
  store

  $ hg update
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  2 files fetched over 1 fetches - (2 misses, 0.00% hit ratio) over *s (glob)

Log on a file without -f

  $ hg log dir/y
  warning: file log can be slow on large repos - use -f to speed it up
  changeset:   1:2e73264fab97
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     y
  
Log on a file with -f

  $ hg log -f dir/y
  changeset:   1:2e73264fab97
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     y
  
Log on a file with kind in path
  $ hg log -r "filelog('path:dir/y')"
  changeset:   1:2e73264fab97
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     y
  
Log on multiple files with -f

  $ hg log -f dir/y x
  changeset:   1:2e73264fab97
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     y
  
  changeset:   0:b292c1e3311f
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     x
  
Log on a directory

  $ hg log dir
  changeset:   1:2e73264fab97
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     y
  
Log on a file from inside a directory

  $ cd dir
  $ hg log y
  warning: file log can be slow on large repos - use -f to speed it up
  changeset:   1:2e73264fab97
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     y
  
Log on a file via -fr
  $ cd ..
  $ hg log -fr tip dir/ --template '{rev}\n'
  1

Trace renames
  $ hg mv x z
  $ hg commit -m move
  $ hg log -f z -T '{desc} {file_copies}\n' -G
  @  move z (x)
  :
  o  x
  

Verify remotefilelog handles rename metadata stripping when comparing file sizes
  $ hg debugrebuilddirstate
  $ hg status