rust: switch hg-core and hg-cpython to rust 2018 edition
Many interesting changes have happened in Rust since the Oxidation Plan was
introduced, like the 2018 edition and procedural macros:
- Opting in to the 2018 edition is a clear benefit in terms of future
proofing, new (nice to have) syntactical sugar notwithstanding. It
also has a new non-lexical, non-AST based borrow checker that has
fewer bugs(!) and allows us to write correct code that in some cases
would have been rejected by the old one.
- Procedural macros allow us to use the PyO3 crate which maintainers have
expressed the clear goal of compiling on stable, which would help in
code maintainability compared to rust-cpython.
In this patch are the following changes:
- Removing most `extern crate` uses
- Updating `use` clauses (`crate` keyword, nested `use`)
- Removing `mod.rs` in favor of an aptly named module file
Like discussed in the mailing list (
https://www.mercurial-scm.org/pipermail/mercurial-devel/2019-July/132316.html
), until Rust integration in Mercurial is considered to be out of the
experimental phase, the maximum version of Rust allowed is whatever the latest
version Debian packages.
Differential Revision: https://phab.mercurial-scm.org/D6597
#require test-repo
$ . "$TESTDIR/helpers-testrepo.sh"
$ testrepohgenv
$ import_checker="$TESTDIR"/../contrib/import-checker.py
Run the doctests from the import checker, and make sure
it's working correctly.
$ TERM=dumb
$ export TERM
$ "$PYTHON" -m doctest $import_checker
Run additional tests for the import checker
$ mkdir testpackage
$ touch testpackage/__init__.py
$ cat > testpackage/multiple.py << EOF
> from __future__ import absolute_import
> import os, sys
> EOF
$ cat > testpackage/unsorted.py << EOF
> from __future__ import absolute_import
> import sys
> import os
> EOF
$ cat > testpackage/stdafterlocal.py << EOF
> from __future__ import absolute_import
> from . import unsorted
> import os
> EOF
$ cat > testpackage/requirerelative.py << EOF
> from __future__ import absolute_import
> import testpackage.unsorted
> EOF
$ cat > testpackage/importalias.py << EOF
> from __future__ import absolute_import
> import ui
> EOF
$ cat > testpackage/relativestdlib.py << EOF
> from __future__ import absolute_import
> from .. import os
> EOF
$ cat > testpackage/symbolimport.py << EOF
> from __future__ import absolute_import
> from .unsorted import foo
> EOF
$ cat > testpackage/latesymbolimport.py << EOF
> from __future__ import absolute_import
> from . import unsorted
> from mercurial.node import hex
> EOF
$ cat > testpackage/multiplegroups.py << EOF
> from __future__ import absolute_import
> from . import unsorted
> from . import more
> EOF
$ mkdir testpackage/subpackage
$ cat > testpackage/subpackage/levelpriority.py << EOF
> from __future__ import absolute_import
> from . import foo
> from .. import parent
> EOF
$ touch testpackage/subpackage/foo.py
$ cat > testpackage/subpackage/__init__.py << EOF
> from __future__ import absolute_import
> from . import levelpriority # should not cause cycle
> EOF
$ cat > testpackage/subpackage/localimport.py << EOF
> from __future__ import absolute_import
> from . import foo
> def bar():
> # should not cause "higher-level import should come first"
> from .. import unsorted
> # but other errors should be detected
> from .. import more
> import testpackage.subpackage.levelpriority
> EOF
$ cat > testpackage/importmodulefromsub.py << EOF
> from __future__ import absolute_import
> from .subpackage import foo # not a "direct symbol import"
> EOF
$ cat > testpackage/importsymbolfromsub.py << EOF
> from __future__ import absolute_import
> from .subpackage import foo, nonmodule
> EOF
$ cat > testpackage/sortedentries.py << EOF
> from __future__ import absolute_import
> from . import (
> foo,
> bar,
> )
> EOF
$ cat > testpackage/importfromalias.py << EOF
> from __future__ import absolute_import
> from . import ui
> EOF
$ cat > testpackage/importfromrelative.py << EOF
> from __future__ import absolute_import
> from testpackage.unsorted import foo
> EOF
$ mkdir testpackage2
$ touch testpackage2/__init__.py
$ cat > testpackage2/latesymbolimport.py << EOF
> from __future__ import absolute_import
> from testpackage import unsorted
> from mercurial.node import hex
> EOF
# Shadowing a stdlib module to test "relative import of stdlib module" is
# allowed if the module is also being checked
$ mkdir email
$ touch email/__init__.py
$ touch email/errors.py
$ cat > email/utils.py << EOF
> from __future__ import absolute_import
> from . import errors
> EOF
$ "$PYTHON" "$import_checker" testpackage*/*.py testpackage/subpackage/*.py \
> email/*.py
testpackage/importalias.py:2: ui module must be "as" aliased to uimod
testpackage/importfromalias.py:2: ui from testpackage must be "as" aliased to uimod
testpackage/importfromrelative.py:2: import should be relative: testpackage.unsorted
testpackage/importfromrelative.py:2: direct symbol import foo from testpackage.unsorted
testpackage/importsymbolfromsub.py:2: direct symbol import nonmodule from testpackage.subpackage
testpackage/latesymbolimport.py:3: symbol import follows non-symbol import: mercurial.node
testpackage/multiple.py:2: multiple imported names: os, sys
testpackage/multiplegroups.py:3: multiple "from . import" statements
testpackage/relativestdlib.py:2: relative import of stdlib module
testpackage/requirerelative.py:2: import should be relative: testpackage.unsorted
testpackage/sortedentries.py:2: imports from testpackage not lexically sorted: bar < foo
testpackage/stdafterlocal.py:3: stdlib import "os" follows local import: testpackage
testpackage/subpackage/levelpriority.py:3: higher-level import should come first: testpackage
testpackage/subpackage/localimport.py:7: multiple "from .. import" statements
testpackage/subpackage/localimport.py:8: import should be relative: testpackage.subpackage.levelpriority
testpackage/symbolimport.py:2: direct symbol import foo from testpackage.unsorted
testpackage/unsorted.py:3: imports not lexically sorted: os < sys
testpackage2/latesymbolimport.py:3: symbol import follows non-symbol import: mercurial.node
[1]