Libcst

Added

- Added `extract`, `extractall` and `replace` functions to Matchers API.

Fixed

- Fixed length restrictions for `AllOf` and `OneOf` so that they can be used with sequence expansion operators.
- Fixed batchable visitors not calling attribute visit functions.
- Fixed typos in docstrings.
- Fixed matcher type exception not being pickleable.

Deprecated

- Deprecated parsing function parameters with defaults into `default_params` attribute. They can be found in the `params` attribute instead.

Fixed

- Fixed broken types for sequence matchers.

Added

- Preliminary support for 3.8 walrus operator.
- CI config and fuzz tests for 3.8.
- Experimental re-entrant codegen API.
- Added `unsafe_skip_copy` optimization to `MetadataWrapper`.
- Matchers API now includes a `findall` function.
- Matchers now have a `MatchMetadataIfTrue` special matcher.

Updated

- Updated to latest Black release.
- Better type documentation for generated matchers.

Fixed

- Clarified matchers documentation in several confusing areas.
- Drastically sped up codegen and tests.
- `QualifiedName` now supports imported attributtes.
- `ExpressionContext` properly marks loop variables as `STORE`.
- Various typos in documentation are fixed.

Deprecated

- Deprecated `BasicPositionProvider` and `SyntacticPositionProvider` in favor of `WhitespaceInclusivePositionProvider` and `PositionProvider`.

Added

- Added `deep_with_changes` helper method on CSTNode.
- Added metadata support to matchers.
- Added ability to get the defining node from a `LocalScope` (`FunctionScope`, `ClassScope` or `ComprehensionScope`).

Updated

- Many changes to LibCST documentation including a new best practices page and updated scope tutorial.
- Exported `CodePosition` and `CodeRange` from `libcst.metadata` instead of `libcst`.

Fixed

- Disallowed decorating a concrete visit or leave method with `visit` or `leave` decorators.
- Renamed position provider classes to be more self-explanatory.
- Fixed trailing newline detection when the last character in a file was from a continuation.
- Fixed `deep_clone` potentially blowing the stack with large LibCST trees.

Deprecated

- Deprecated `ExtSlice` in favor of `SubscriptElement`.
- Deprecated parsing `Subscript` slices directly into `Index` or `Slice` nodes.

Added

- `Scope.assignments` and `Scope.accesses` APIs to access all references in a scope.
- Scope analysis tutorial.

Updated

- Supported `<comprehension>` in `Scope.get_qualified_names_for` and `QualifiedName`.
- Enforced identity equality for matchers and immutability of non-dataclass matchers.
- Generalize codegen cleanup steps for all codegen.

Fixed

- Made `BatchableMetadataProvider` typing covariant over its typevar.
- Fixed LICENSE header on generated matcher file.
- Cleanup unused internal noqa and on-call specification.

Added

- Added matchers which allow comparing LibCST trees against arbitrary patterns.
- Improved tree manipulation with `deep_remove` and `deep_replace` helper methods on CSTNode.
- Added new metadata providers: parent node and qualified name.

Updated

- Updated Pyre to latest release.
- Updated scope metadata to provide additional helpers.
- Updated preferred method of removing a node from its parent in a visitor.

Fixed

- Metadata classes and methods are now exported from "libcst.metadata" instead of several submodules.
- Fixed LICENSE file to explicitly reference individual files in the repo with different licenses.
- Fixed `deep_clone` to correctly clone leaf nodes.
- Fixed all parse entrypoints to always return a tree with no duplicated leaf nodes.