Instagram/LibCST

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A concrete syntax tree parser and serializer library for Python that preserves many aspects of Python's abstract syntax tree

Stars: 1.9k
Forks: 229
Open beginner issues: 0
Indexed issues: 130

Dominant language: Python
License: No license data
Last GitHub push: Aug 11, 2026
Latest indexed: Sep 17, 2026
Contributing guide: Contributing guide
Code of conduct: Code of conduct
Beginner labels: good first issue help wanted
PR merge metrics: No merged PRs in 30d

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130 open issues indexed

[low-pri][doc] Add document to explain the design differences between libcst and ast Open

documentation

Instagram/LibCST#77 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 17, 2026
Handle string escaping for SimpleString expression in FormattedString Open

parsing

Instagram/LibCST#219 · 1 comment · 0 reactions · 0 assignees · Indexed Sep 17, 2026
[feature][metadata] add SuperClassProvider Open

codemod

Instagram/LibCST#273 · 0 comments · 1 reaction · 0 assignees · Indexed Sep 17, 2026
Cannot deep_replace multiple nodes Open

enhancement machinery

Instagram/LibCST#277 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 17, 2026
Parsing Code with Syntax Errors Open

enhancement parsing

Instagram/LibCST#310 · 2 comments · 0 reactions · 0 assignees · Indexed Sep 17, 2026
Steal tests from retype for ApplyTypeAnnotationsVisitor Open

codemod

Instagram/LibCST#316 · 1 comment · 0 reactions · 0 assignees · Indexed Sep 17, 2026
Make .libcst.codemod.yaml location an optional argument for CLI usage Open

machinery

Instagram/LibCST#317 · 1 comment · 0 reactions · 0 assignees · Indexed Sep 17, 2026
Merge class attribute annotations in ApplyTypeAnnotationsVisitor Open

codemod

Instagram/LibCST#323 · 4 comments · 0 reactions · 0 assignees · Indexed Sep 17, 2026
Scope metadata doesn't include instance variables Open

codemod enhancement good first issue

Instagram/LibCST#328 · 1 comment · 0 reactions · 0 assignees · Indexed Sep 17, 2026
Test errors on openSUSE Open

Instagram/LibCST#331 · 12 comments · 0 reactions · 0 assignees · Indexed Sep 17, 2026
TypeInferenceProvider gen_cache() raises `[Errno 7] Argument list too long` Open

codemod

Instagram/LibCST#332 · 2 comments · 0 reactions · 0 assignees · Indexed Sep 17, 2026
[FR] Add replaceShallow function to matchers Open

machinery

Instagram/LibCST#339 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 17, 2026
[BUG] Generated Code not equivalent to AST Open

Instagram/LibCST#341 · 11 comments · 0 reactions · 0 assignees · Indexed Sep 17, 2026
Several tests failing on Guix Open

Instagram/LibCST#347 · 4 comments · 0 reactions · 0 assignees · Indexed Sep 17, 2026
QualifiedNameProvider provides incorrect builtins.None name. Open

bug codemod

Instagram/LibCST#389 · 1 comment · 0 reactions · 0 assignees · Indexed Sep 17, 2026
@leave decorator matches against original node, not updated node Open

machinery

Instagram/LibCST#399 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 17, 2026
Associate comment of first statement properly in a Module Open

parsing

Instagram/LibCST#405 · 4 comments · 0 reactions · 0 assignees · Indexed Sep 17, 2026
Assigned visit_* methods not being called in BatchableMetadataProvider Open

machinery

Instagram/LibCST#407 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 17, 2026
[RFC] Add `.code` to statements and expressions Open

enhancement

Instagram/LibCST#408 · 2 comments · 2 reactions · 0 assignees · Indexed Sep 17, 2026
Recursion limit exceeded while visiting implicit joins Open

machinery

Instagram/LibCST#409 · 3 comments · 1 reaction · 0 assignees · Indexed Sep 17, 2026
Extract properties from class defs to common superclass Open

codemod

Instagram/LibCST#427 · 3 comments · 0 reactions · 0 assignees · Indexed Sep 17, 2026
Allow external codemods to be registered via setuptools entry points Open

enhancement machinery

Instagram/LibCST#434 · 0 comments · 1 reaction · 0 assignees · Indexed Sep 17, 2026
`QualifiedNameProvider` assigns incorrect qualname to return value from a decorator Open

codemod

Instagram/LibCST#437 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 17, 2026
Validation for with...as too strict Open

bug parsing

Instagram/LibCST#439 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 17, 2026
CSTTransform.on_leave type definitions are too strict Open

machinery

Instagram/LibCST#441 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 17, 2026
`_INDENT_RE` is too narrow - `'\x0c '` is strange but valid indent whitespace Open

bug parsing

Instagram/LibCST#446 · 4 comments · 0 reactions · 0 assignees · Indexed Sep 17, 2026
Documentation example doesn't work out of the box: metadata provider Open

documentation good first issue help wanted

Instagram/LibCST#449 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 17, 2026
Docs: Tutorial prose poorly rendered in mybinder Open

documentation enhancement

Instagram/LibCST#450 · 1 comment · 0 reactions · 0 assignees · Indexed Sep 17, 2026
TypeInferenceProvider using another tool than pyre - Jedi Open

codemod enhancement

Instagram/LibCST#451 · 8 comments · 3 reactions · 0 assignees · Indexed Sep 17, 2026
Remove `with self.assertRaises(Exception):` Open

good first issue

Instagram/LibCST#457 · 1 comment · 0 reactions · 0 assignees · Indexed Sep 17, 2026
AnnAssign allows invalid whitespace around equals Open

bug parsing

Instagram/LibCST#488 · 4 comments · 0 reactions · 0 assignees · Indexed Sep 17, 2026
RemoveUnusedImports codemod incorrectly removes this Open

bug codemod

Instagram/LibCST#498 · 1 comment · 1 reaction · 0 assignees · Indexed Sep 17, 2026
`Assign.value` has incorrect type annotation Open

documentation good first issue parsing

Instagram/LibCST#501 · 4 comments · 0 reactions · 1 assignee · Indexed Sep 17, 2026
`AsName.name` has incorrect type annotations Open

documentation good first issue parsing

Instagram/LibCST#503 · 3 comments · 0 reactions · 0 assignees · Indexed Sep 17, 2026
StarredDictElement can produce syntactically incorrect output Open

bug parsing

Instagram/LibCST#519 · 2 comments · 0 reactions · 0 assignees · Indexed Sep 17, 2026
QualifiedNameProvider does not provide qualified name for keyword arguments. Open

bug codemod

Instagram/LibCST#520 · 2 comments · 0 reactions · 0 assignees · Indexed Sep 17, 2026
`ParserSyntaxError` on `from foo import (bar \n as baz)` Open

bug parsing

Instagram/LibCST#530 · 4 comments · 0 reactions · 0 assignees · Indexed Sep 17, 2026
Invalid code generated by removing parens from `Call` node Open

bug parsing

Instagram/LibCST#531 · 1 comment · 0 reactions · 0 assignees · Indexed Sep 17, 2026
ImportFrom can produce invalid code without parenthesis Open

bug parsing

Instagram/LibCST#532 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 17, 2026
Codemod to convert typing.Union and typing.Optional to PEP 604 `|` Open

codemod enhancement

Instagram/LibCST#535 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 17, 2026
Codemod to convert assignments to augmented assignments Open

codemod enhancement good first issue

Instagram/LibCST#541 · 2 comments · 0 reactions · 0 assignees · Indexed Sep 17, 2026
Using inverse of matcher errors for visit decorators Open

bug machinery

Instagram/LibCST#544 · 1 comment · 0 reactions · 0 assignees · Indexed Sep 17, 2026
Deeply nested binary arithmetic segfaults under native parser Open

bug parsing

Instagram/LibCST#619 · 7 comments · 0 reactions · 0 assignees · Indexed Sep 17, 2026
Improve ParserSyntaxError messages for parse_expression and parse_statement Open

enhancement parsing

Instagram/LibCST#645 · 1 comment · 0 reactions · 0 assignees · Indexed Sep 17, 2026
`ValueError` when using `FullyQualifiedNameProvider` Open

bug codemod

Instagram/LibCST#722 · 1 comment · 0 reactions · 0 assignees · Indexed Sep 17, 2026
Scratch dictionary being prematurely emptied in codemod Open

Instagram/LibCST#727 · 0 comments · 0 reactions · 0 assignees · Indexed Sep 17, 2026
Add support for limiting the native parser to a certain Python version Open

enhancement parsing rust

Instagram/LibCST#740 · 1 comment · 1 reaction · 0 assignees · Indexed Sep 17, 2026
Clarifying expression context of import statements Open

Instagram/LibCST#761 · 3 comments · 0 reactions · 0 assignees · Indexed Sep 17, 2026
No 3.7 macosx-arm64 wheels Open

Instagram/LibCST#768 · 5 comments · 0 reactions · 0 assignees · Indexed Sep 17, 2026
Supported Python versions Open

question

Instagram/LibCST#776 · 2 comments · 0 reactions · 0 assignees · Indexed Sep 17, 2026

Instagram/LibCST

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