view tests/test-mq-missingfiles.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

Issue835: qpush fails immediately when patching a missing file, but
remaining added files are still created empty which will trick a
future qrefresh.

  $ cat > writelines.py <<EOF
  > import sys
  > if sys.version_info[0] >= 3:
  >     encode = lambda x: x.encode('utf-8').decode('unicode_escape').encode('utf-8')
  > else:
  >     encode = lambda x: x.decode('string_escape')
  > path = sys.argv[1]
  > args = sys.argv[2:]
  > assert (len(args) % 2) == 0
  > 
  > f = open(path, 'wb')
  > for i in range(len(args) // 2):
  >    count, s = args[2 * i:2 * i + 2]
  >    count = int(count)
  >    s = encode(s)
  >    f.write(s * count)
  > f.close()
  > EOF

  $ echo "[extensions]" >> $HGRCPATH
  $ echo "mq=" >> $HGRCPATH

  $ hg init normal
  $ cd normal
  $ "$PYTHON" ../writelines.py b 10 'a\n'
  $ hg ci -Am addb
  adding b
  $ echo a > a
  $ "$PYTHON" ../writelines.py b 2 'b\n' 10 'a\n' 2 'c\n'
  $ echo c > c
  $ hg add a c
  $ hg qnew -f changeb
  $ hg qpop
  popping changeb
  patch queue now empty
  $ hg rm b
  $ hg ci -Am rmb

Push patch with missing target:

  $ hg qpush
  applying changeb
  unable to find 'b' for patching
  (use '--prefix' to apply patch relative to the current directory)
  2 out of 2 hunks FAILED -- saving rejects to file b.rej
  patch failed, unable to continue (try -v)
  patch failed, rejects left in working directory
  errors during apply, please fix and qrefresh changeb
  [2]

Display added files:

  $ cat a
  a
  $ cat c
  c

Display rejections:

  $ cat b.rej
  --- b
  +++ b
  @@ -1,3 +1,5 @@
  +b
  +b
   a
   a
   a
  @@ -8,3 +10,5 @@
   a
   a
   a
  +c
  +c

Test missing renamed file

  $ hg qpop
  popping changeb
  patch queue now empty
  $ hg up -qC 0
  $ echo a > a
  $ hg mv b bb
  $ "$PYTHON" ../writelines.py bb 2 'b\n' 10 'a\n' 2 'c\n'
  $ echo c > c
  $ hg add a c
  $ hg qnew changebb
  $ hg qpop
  popping changebb
  patch queue now empty
  $ hg up -qC 1
  $ hg qpush
  applying changebb
  patching file bb
  Hunk #1 FAILED at 0
  Hunk #2 FAILED at 7
  2 out of 2 hunks FAILED -- saving rejects to file bb.rej
  b not tracked!
  patch failed, unable to continue (try -v)
  patch failed, rejects left in working directory
  errors during apply, please fix and qrefresh changebb
  [2]
  $ cat a
  a
  $ cat c
  c
  $ cat bb.rej
  --- bb
  +++ bb
  @@ -1,3 +1,5 @@
  +b
  +b
   a
   a
   a
  @@ -8,3 +10,5 @@
   a
   a
   a
  +c
  +c

  $ cd ..


  $ echo "[diff]" >> $HGRCPATH
  $ echo "git=1" >> $HGRCPATH

  $ hg init git
  $ cd git
  $ "$PYTHON" ../writelines.py b 1 '\x00'
  $ hg ci -Am addb
  adding b
  $ echo a > a
  $ "$PYTHON" ../writelines.py b 1 '\x01' 1 '\x00'
  $ echo c > c
  $ hg add a c
  $ hg qnew -f changeb
  $ hg qpop
  popping changeb
  patch queue now empty
  $ hg rm b
  $ hg ci -Am rmb

Push git patch with missing target:

  $ hg qpush
  applying changeb
  unable to find 'b' for patching
  (use '--prefix' to apply patch relative to the current directory)
  1 out of 1 hunks FAILED -- saving rejects to file b.rej
  patch failed, unable to continue (try -v)
  patch failed, rejects left in working directory
  errors during apply, please fix and qrefresh changeb
  [2]
  $ hg st
  ? b.rej

Display added files:

  $ cat a
  a
  $ cat c
  c

Display rejections:

  $ cat b.rej
  --- b
  +++ b
  GIT binary patch
  literal 2
  Jc${No0000400IC2
  
  $ cd ..

Test push creating directory during git copy or rename:

  $ hg init missingdir
  $ cd missingdir
  $ echo a > a
  $ hg ci -Am adda
  adding a
  $ mkdir d
  $ hg copy a d/a2
  $ hg mv a d/a
  $ hg qnew -g -f patch
  $ hg qpop
  popping patch
  patch queue now empty
  $ hg qpush
  applying patch
  now at: patch

  $ cd ..