Include decorators in Class and FunctionDef range

[MichaReiser]

This PR changes the ClassDef and FunctionDef definitions to include the range of their decorators.

Example

@test
def f(): 
	pass

• Before: The functions' range was from line 2, column 0 to line 3, column 9
• New: The functions' range spans from line 1, column 0 to line 3, column 9 (includes the @test decorator)

Motivation

This change is because these are the only nodes for where the property parent.range.includes(child.range) does not hold. The fact that this property is not respected means it is e.g. impossible to use a binary search over the AST to find a node by its range.

Downsides

The main downside that I'm aware of is that diagnostics using range.start to compute the line index for functions and classes may now incorrectly point to the line of the function's decorator instead of the function definition. I don't know if this is a problem for RustPython. Ruff already uses custom infrastructure to extract the range of the function name only to limit the diagnostic range (and e.g. avoid highlighting the whole function or class including the body)

Alternatives

An alternative to this would be to change our AST and introduce a new DecoratedDefinition node that includes the decorator and the Function or Class definition. This is what tree-sitter does.

Related

• Ruff Include decorators in Function and Class definition ranges ruff#4467
• Upstream PR where we decided to only change this in Ruff's fork Reduce copying during parsing RustPython/Parser#60

[MichaReiser]

Current dependencies on/for this PR:

• main
  • PR Include decorators in Class and FunctionDef range #2 👈

This comment was auto-generated by Graphite.

[charliermarsh]

This will require changes in Ruff.

[MichaReiser]

This will require changes in Ruff.

Related PR: astral-sh/ruff#4467