view tests/test-check-pytype.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 pytype py3 slow

  $ cd $RUNTESTDIR/..

Many of the individual files that are excluded here confuse pytype
because they do a mix of Python 2 and Python 3 things
conditionally. There's no good way to help it out with that as far as
I can tell, so let's just hide those files from it for now. We should
endeavor to empty this list out over time, as some of these are
probably hiding real problems.

mercurial/bundlerepo.py       # no vfs and ui attrs on bundlerepo
mercurial/context.py          # many [attribute-error]
mercurial/crecord.py          # tons of [attribute-error], [module-attr]
mercurial/debugcommands.py    # [wrong-arg-types]
mercurial/dispatch.py         # initstdio: No attribute ... on TextIO [attribute-error]
mercurial/exchange.py         # [attribute-error]
mercurial/hgweb/hgweb_mod.py  # [attribute-error], [name-error], [wrong-arg-types]
mercurial/hgweb/server.py     # [attribute-error], [name-error], [module-attr]
mercurial/hgweb/wsgicgi.py    # confused values in os.environ
mercurial/httppeer.py         # [attribute-error], [wrong-arg-types]
mercurial/interfaces          # No attribute 'capabilities' on peer [attribute-error]
mercurial/keepalive.py        # [attribute-error]
mercurial/localrepo.py        # [attribute-error]
mercurial/manifest.py         # [unsupported-operands], [wrong-arg-types]
mercurial/minirst.py          # [unsupported-operands], [attribute-error]
mercurial/pure/osutil.py      # [invalid-typevar], [not-callable]
mercurial/pure/parsers.py     # [attribute-error]
mercurial/repoview.py         # [attribute-error]
mercurial/testing/storage.py  # tons of [attribute-error]
mercurial/ui.py               # [attribute-error], [wrong-arg-types]
mercurial/unionrepo.py        # ui, svfs, unfiltered [attribute-error]
mercurial/utils/memorytop.py  # not 3.6 compatible
mercurial/win32.py            # [not-callable]
mercurial/wireprotoframing.py # [unsupported-operands], [attribute-error], [import-error]
mercurial/wireprotov1peer.py  # [attribute-error]
mercurial/wireprotov1server.py  # BUG?: BundleValueError handler accesses subclass's attrs

TODO: use --no-cache on test server?  Caching the files locally helps during
development, but may be a hinderance for CI testing.

  $ pytype -V 3.6 --keep-going --jobs auto mercurial \
  >    -x mercurial/bundlerepo.py \
  >    -x mercurial/context.py \
  >    -x mercurial/crecord.py \
  >    -x mercurial/debugcommands.py \
  >    -x mercurial/dispatch.py \
  >    -x mercurial/exchange.py \
  >    -x mercurial/hgweb/hgweb_mod.py \
  >    -x mercurial/hgweb/server.py \
  >    -x mercurial/hgweb/wsgicgi.py \
  >    -x mercurial/httppeer.py \
  >    -x mercurial/interfaces \
  >    -x mercurial/keepalive.py \
  >    -x mercurial/localrepo.py \
  >    -x mercurial/manifest.py \
  >    -x mercurial/minirst.py \
  >    -x mercurial/pure/osutil.py \
  >    -x mercurial/pure/parsers.py \
  >    -x mercurial/repoview.py \
  >    -x mercurial/testing/storage.py \
  >    -x mercurial/thirdparty \
  >    -x mercurial/ui.py \
  >    -x mercurial/unionrepo.py \
  >    -x mercurial/utils/memorytop.py \
  >    -x mercurial/win32.py \
  >    -x mercurial/wireprotoframing.py \
  >    -x mercurial/wireprotov1peer.py \
  >    -x mercurial/wireprotov1server.py \
  >  > $TESTTMP/pytype-output.txt || cat $TESTTMP/pytype-output.txt

Only show the results on a failure, because the output on success is also
voluminous and variable.