view tests/test-mq-git.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 the plumbing of mq.git option
# Automatic upgrade itself is tested elsewhere.

  $ cat <<EOF >> $HGRCPATH
  > [extensions]
  > mq =
  > [diff]
  > nodates = 1
  > EOF

  $ hg init repo-auto
  $ cd repo-auto

git=auto: regular patch creation:

  $ echo a > a
  $ hg add a
  $ hg qnew -d '0 0' -f adda

  $ cat .hg/patches/adda
  # HG changeset patch
  # Date 0 0
  # Parent  0000000000000000000000000000000000000000
  
  diff -r 000000000000 -r ef8dafc9fa4c a
  --- /dev/null
  +++ b/a
  @@ -0,0 +1,1 @@
  +a

git=auto: git patch creation with copy:

  $ hg cp a b
  $ hg qnew -d '0 0' -f copy

  $ cat .hg/patches/copy
  # HG changeset patch
  # Date 0 0
  # Parent  ef8dafc9fa4caff80f6e243eb0171bcd60c455b4
  
  diff --git a/a b/b
  copy from a
  copy to b

git=auto: git patch when using --git:

  $ echo regular > regular
  $ hg add regular
  $ hg qnew -d '0 0' --git -f git

  $ cat .hg/patches/git
  # HG changeset patch
  # Date 0 0
  # Parent  99586d5f048c399e20f81cee41fbb3809c0e735d
  
  diff --git a/regular b/regular
  new file mode 100644
  --- /dev/null
  +++ b/regular
  @@ -0,0 +1,1 @@
  +regular

git=auto: regular patch after qrefresh without --git:

  $ hg qrefresh -d '0 0'

  $ cat .hg/patches/git
  # HG changeset patch
  # Date 0 0
  # Parent  99586d5f048c399e20f81cee41fbb3809c0e735d
  
  diff -r 99586d5f048c regular
  --- /dev/null
  +++ b/regular
  @@ -0,0 +1,1 @@
  +regular

  $ cd ..

  $ hg init repo-keep
  $ cd repo-keep
  $ echo '[mq]' > .hg/hgrc
  $ echo 'git = KEEP' >> .hg/hgrc

git=keep: git patch with --git:

  $ echo a > a
  $ hg add a
  $ hg qnew -d '0 0' -f --git git

  $ cat .hg/patches/git
  # HG changeset patch
  # Date 0 0
  # Parent  0000000000000000000000000000000000000000
  
  diff --git a/a b/a
  new file mode 100644
  --- /dev/null
  +++ b/a
  @@ -0,0 +1,1 @@
  +a

git=keep: git patch after qrefresh without --git:

  $ echo a >> a
  $ hg qrefresh -d '0 0'

  $ cat .hg/patches/git
  # HG changeset patch
  # Date 0 0
  # Parent  0000000000000000000000000000000000000000
  
  diff --git a/a b/a
  new file mode 100644
  --- /dev/null
  +++ b/a
  @@ -0,0 +1,2 @@
  +a
  +a
  $ cd ..

  $ hg init repo-yes
  $ cd repo-yes
  $ echo '[mq]' > .hg/hgrc
  $ echo 'git = yes' >> .hg/hgrc

git=yes: git patch:

  $ echo a > a
  $ hg add a
  $ hg qnew -d '0 0' -f git

  $ cat .hg/patches/git
  # HG changeset patch
  # Date 0 0
  # Parent  0000000000000000000000000000000000000000
  
  diff --git a/a b/a
  new file mode 100644
  --- /dev/null
  +++ b/a
  @@ -0,0 +1,1 @@
  +a

git=yes: git patch after qrefresh:

  $ echo a >> a
  $ hg qrefresh -d '0 0'

  $ cat .hg/patches/git
  # HG changeset patch
  # Date 0 0
  # Parent  0000000000000000000000000000000000000000
  
  diff --git a/a b/a
  new file mode 100644
  --- /dev/null
  +++ b/a
  @@ -0,0 +1,2 @@
  +a
  +a
  $ cd ..

  $ hg init repo-no
  $ cd repo-no
  $ echo '[diff]' > .hg/hgrc
  $ echo 'git = True' >> .hg/hgrc
  $ echo '[mq]' > .hg/hgrc
  $ echo 'git = False' >> .hg/hgrc

git=no: regular patch with copy:

  $ echo a > a
  $ hg add a
  $ hg qnew -d '0 0' -f adda
  $ hg cp a b
  $ hg qnew -d '0 0' -f regular

  $ cat .hg/patches/regular
  # HG changeset patch
  # Date 0 0
  # Parent  ef8dafc9fa4caff80f6e243eb0171bcd60c455b4
  
  diff -r ef8dafc9fa4c -r a70404f79ba3 b
  --- /dev/null
  +++ b/b
  @@ -0,0 +1,1 @@
  +a

git=no: regular patch after qrefresh with copy:

  $ hg cp a c
  $ hg qrefresh -d '0 0'

  $ cat .hg/patches/regular
  # HG changeset patch
  # Date 0 0
  # Parent  ef8dafc9fa4caff80f6e243eb0171bcd60c455b4
  
  diff -r ef8dafc9fa4c b
  --- /dev/null
  +++ b/b
  @@ -0,0 +1,1 @@
  +a
  diff -r ef8dafc9fa4c c
  --- /dev/null
  +++ b/c
  @@ -0,0 +1,1 @@
  +a

Test how [diff] configuration influence and cause invalid or lossy patches:

  $ cat <<EOF >> .hg/hgrc
  > [mq]
  > git = AUTO
  > [diff]
  > nobinary = True
  > noprefix = True
  > showfunc = True
  > ignorews = True
  > ignorewsamount = True
  > ignoreblanklines = True
  > unified = 1
  > EOF

  $ echo ' a' > a
  $ hg qnew prepare -d '0 0'
  $ echo '  a' > a
  $ printf '\0' > b
  $ echo >> c
  $ hg qnew diff -d '0 0'

  $ cat .hg/patches/prepare
  # HG changeset patch
  # Date 0 0
  # Parent  cf0bfe72686a47d8d7d7b4529a3adb8b0b449a9f
  
  diff -r cf0bfe72686a -r fb9c4422b0f3 a
  --- a/a
  +++ b/a
  @@ -1,1 +1,1 @@
  -a
  + a
  $ cat .hg/patches/diff
  # HG changeset patch
  # Date 0 0
  # Parent  fb9c4422b0f37dd576522dd9a3f99b825c177efe
  
  diff --git a/a b/a
  --- a/a
  +++ b/a
  @@ -1,1 +1,1 @@
  - a
  +  a
  diff --git a/b b/b
  index 78981922613b2afb6025042ff6bd878ac1994e85..f76dd238ade08917e6712764a16a22005a50573d
  GIT binary patch
  literal 1
  Ic${MZ000310RR91
  
  diff --git a/c b/c
  --- a/c
  +++ b/c
  @@ -1,1 +1,2 @@
   a
  +

  $ cd ..