view tests/test-narrow-pull.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

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

  $ hg init master
  $ cd master
  $ cat >> .hg/hgrc <<EOF
  > [narrow]
  > serveellipses=True
  > EOF
  $ for x in `$TESTDIR/seq.py 10`
  > do
  >   echo $x > "f$x"
  >   hg add "f$x"
  >   hg commit -m "Commit f$x"
  > done
  $ cd ..

narrow clone a couple files, f2 and f8

  $ hg clone --narrow ssh://user@dummy/master narrow --include "f2" --include "f8"
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 5 changesets with 2 changes to 2 files
  new changesets *:* (glob)
  updating to branch default
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd narrow
  $ ls -A
  .hg
  f2
  f8
  $ cat f2 f8
  2
  8

  $ cd ..

change every upstream file twice

  $ cd master
  $ for x in `$TESTDIR/seq.py 10`
  > do
  >   echo "update#1 $x" >> "f$x"
  >   hg commit -m "Update#1 to f$x" "f$x"
  > done
  $ for x in `$TESTDIR/seq.py 10`
  > do
  >   echo "update#2 $x" >> "f$x"
  >   hg commit -m "Update#2 to f$x" "f$x"
  > done
  $ cd ..

look for incoming changes

  $ cd narrow
  $ hg incoming --limit 3
  comparing with ssh://user@dummy/master
  searching for changes
  changeset:   5:ddc055582556
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     Update#1 to f1
  
  changeset:   6:f66eb5ad621d
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     Update#1 to f2
  
  changeset:   7:c42ecff04e99
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     Update#1 to f3
  

Interrupting the pull is safe
  $ hg --config hooks.pretxnchangegroup.bad=false pull -q
  transaction abort!
  rollback completed
  abort: pretxnchangegroup.bad hook exited with status 1
  [40]
  $ hg id
  223311e70a6f tip

pull new changes down to the narrow clone. Should get 8 new changesets: 4
relevant to the narrow spec, and 4 ellipsis nodes gluing them all together.

  $ hg pull
  pulling from ssh://user@dummy/master
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 9 changesets with 4 changes to 2 files
  new changesets *:* (glob)
  (run 'hg update' to get a working copy)
  $ hg log -T '{rev}: {desc}\n'
  13: Update#2 to f10
  12: Update#2 to f8
  11: Update#2 to f7
  10: Update#2 to f2
  9: Update#2 to f1
  8: Update#1 to f8
  7: Update#1 to f7
  6: Update#1 to f2
  5: Update#1 to f1
  4: Commit f10
  3: Commit f8
  2: Commit f7
  1: Commit f2
  0: Commit f1
  $ hg update tip
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved

add a change and push it

  $ echo "update#3 2" >> f2
  $ hg commit -m "Update#3 to f2" f2
  $ hg log f2 -T '{rev}: {desc}\n'
  14: Update#3 to f2
  10: Update#2 to f2
  6: Update#1 to f2
  1: Commit f2
  $ hg push
  pushing to ssh://user@dummy/master
  searching for changes
  remote: adding changesets
  remote: adding manifests
  remote: adding file changes
  remote: added 1 changesets with 1 changes to 1 files
  $ cd ..

  $ cd master
  $ hg log f2 -T '{rev}: {desc}\n'
  30: Update#3 to f2
  21: Update#2 to f2
  11: Update#1 to f2
  1: Commit f2
  $ hg log -l 3 -T '{rev}: {desc}\n'
  30: Update#3 to f2
  29: Update#2 to f10
  28: Update#2 to f9

Can pull into repo with a single commit

  $ cd ..
  $ hg clone -q --narrow ssh://user@dummy/master narrow2 --include "f1" -r 0
  $ cd narrow2
  $ hg pull -q -r 1
  remote: abort: unexpected error: unable to resolve parent while packing '00manifest' 1 for changeset 0
  transaction abort!
  rollback completed
  abort: pull failed on remote
  [100]