Caches file path information on the root `Module` node.
Resolves paths when caching, so they are always absolute paths.
Adds a new `chdir` helper to change working directory and automatically
revert to previous directory, which makes testing file paths with the
`"."` repo root easier.
ghstack-source-id: 3413905fc1
Pull Request resolved: https://github.com/Instagram/LibCST/pull/892
In certain cases (e.g. inside Instagram's lint framework) we know that
our tree originates from the parser, so we know that there shouldn't be
any duplicate nodes in our tree.
MetadataWrapper exists to copy the tree ensuring that there's no
duplicate nodes.
This diff provides an escape hatch on MetadataWrapper that allows us to
save a little time and avoid a copy when we know that it's safe to skip
the copy.
As part of this, I ran into some issues with `InitVar` and pyre, so I
removed `@dataclass` from the class. This means that this is techincally
a breaking change if someone depended on the MetadataWrapper being an
actual dataclass, but I think this is unlikely. I implemented `__repr__`
and added tests for hashing/equality behavior.
While these classes are used by the codegen implementation, conceptually
they're part of `libcst.metadata`, so we should export them from
`libcst.metadata` instead of the top-level `libcst` package.
I discussed the high-level idea here with @DragonMinded a few months
ago, but this isn't set in stone. If people have better ideas for names,
I'd love to hear it.
Publicly-Visible Changes
------------------------
- SyntacticPositionProvider is deprecated. The new name is
PositionProvider.
- BasicPositionProvider is deprecated. The new name is
WhitespaceInclusivePositionProvider.
- Documentation is updated to better explain these renamed providers and
how to use them.
The prefixes "Syntactic" and "Basic" were pretty bad because they're
just concepts that we made up for LibCST.
The idea for the new names is that most users will want the
SyntacticPositionProvider, and so we should name things so that the user
will naturally gravitate towards the correct choice.
There's some argument that we shouldn't even bother exposing
WhitespaceInclusivePositionProvider, but we already need to implement it
as a fallback for PositionProvider, and it might be useful for some
niche use-cases.
Once we have another major version bump, we can remove the old class
names. The old class names have already be removed from the
documentation so that new users aren't tempted to use them.
Internal-Only Changes
---------------------
- `PositionProvider` is now `_PositionProviderUnion`. This type alias
was never a public API (and probably never will be).
- `BasicCodegenState` is now
`WhitespaceInclusivePositionProvidingCodegenState`.
- `SyntacticCodegenState` is now `PositionProvidingCodegenState`.
Explaining the implementation details of scopes to someone unfamiliar
with compilers can be tricky. Hopefully this helps.
- Rephrased the definition of a scope to be more applicable to Python
(remove references to "blocks"), and made it use an example for
(hopefully) better clarity.
- New scopes are also created for comprehensions.
- Set a fixed width (400px) for the scope diagram, since it was too
large before.
- Tweaked some tenses.
- Add a final call to action: "LibCST allows you to inspect these
scopes"
