view tests/test-convert-svn-branches.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 svn svn-bindings

  $ cat >> $HGRCPATH <<EOF
  > [extensions]
  > convert =
  > EOF

  $ svnadmin create svn-repo
  $ svnadmin load -q svn-repo < "$TESTDIR/svn/branches.svndump"

Convert trunk and branches

  $ cat > branchmap <<EOF
  > old3 newbranch
  > 
  > 
  > EOF
  $ hg convert --branchmap=branchmap --datesort -r 10 svn-repo A-hg
  initializing destination A-hg repository
  scanning source...
  sorting...
  converting...
  10 init projA
  9 hello
  8 branch trunk, remove c and dir
  7 change a
  6 change b
  5 move and update c
  4 move and update c
  3 change b again
  2 move to old2
  1 move back to old
  0 last change to a

Test template keywords

  $ hg -R A-hg log --template '{rev} {svnuuid}{svnpath}@{svnrev}\n'
  10 644ede6c-2b81-4367-9dc8-d786514f2cde/trunk@10
  9 644ede6c-2b81-4367-9dc8-d786514f2cde/branches/old@9
  8 644ede6c-2b81-4367-9dc8-d786514f2cde/branches/old2@8
  7 644ede6c-2b81-4367-9dc8-d786514f2cde/branches/old@7
  6 644ede6c-2b81-4367-9dc8-d786514f2cde/trunk@6
  5 644ede6c-2b81-4367-9dc8-d786514f2cde/branches/old@6
  4 644ede6c-2b81-4367-9dc8-d786514f2cde/branches/old@5
  3 644ede6c-2b81-4367-9dc8-d786514f2cde/trunk@4
  2 644ede6c-2b81-4367-9dc8-d786514f2cde/branches/old@3
  1 644ede6c-2b81-4367-9dc8-d786514f2cde/trunk@2
  0 644ede6c-2b81-4367-9dc8-d786514f2cde/trunk@1

Convert again

  $ hg convert --branchmap=branchmap --datesort svn-repo A-hg
  scanning source...
  sorting...
  converting...
  0 branch trunk@1 into old3

  $ cd A-hg
  $ hg log -G --template 'branch={branches} {rev} {desc|firstline} files: {files}\n'
  o  branch=newbranch 11 branch trunk@1 into old3 files:
  |
  | o  branch= 10 last change to a files: a
  | |
  | | o  branch=old 9 move back to old files:
  | | |
  | | o  branch=old2 8 move to old2 files:
  | | |
  | | o  branch=old 7 change b again files: b
  | | |
  | o |  branch= 6 move and update c files: b
  | | |
  | | o  branch=old 5 move and update c files: c
  | | |
  | | o  branch=old 4 change b files: b
  | | |
  | o |  branch= 3 change a files: a
  | | |
  | | o  branch=old 2 branch trunk, remove c and dir files: c
  | |/
  | o  branch= 1 hello files: a b c dir/e
  |/
  o  branch= 0 init projA files:
  

  $ hg branches
  newbranch                     11:a6d7cc050ad1
  default                       10:6e2b33404495
  old                            9:1b494af68c0b
  old2                           8:5be40b8dcbf6 (inactive)
  $ hg tags -q
  tip
  $ cd ..

Test hg failing to call itself

  $ HG=foobar hg convert svn-repo B-hg 2>&1 | grep abort
  abort: Mercurial failed to run itself, check hg executable is in PATH

Convert 'trunk' to branch other than 'default'

  $ cat > branchmap <<EOF
  > default hgtrunk
  > 
  > 
  > EOF
  $ hg convert --branchmap=branchmap --datesort -r 10 svn-repo C-hg
  initializing destination C-hg repository
  scanning source...
  sorting...
  converting...
  10 init projA
  9 hello
  8 branch trunk, remove c and dir
  7 change a
  6 change b
  5 move and update c
  4 move and update c
  3 change b again
  2 move to old2
  1 move back to old
  0 last change to a

  $ cd C-hg
  $ hg branches --template '{branch}\n'
  hgtrunk
  old
  old2
  $ cd ..