According to https://docs.python.org/3/library/ast.html#ast-helpers, we expect type_ignores to be always be empty, so this adds a debug assert.
Test plan: I confirmed that the assertion holdes for the file below and for all the black tests which include a number of `type: ignore` comments.
```python
# type: ignore
if 1:
print("1") # type: ignore
# elsebranch
# type: ignore
else: # type: ignore
print("2") # type: ignore
while 1:
print()
# type: ignore
```
* Implement module formatting using JoinNodesBuilder
This uses JoinNodesBuilder to implement module formatting for #4800
See the snapshots for the changed behaviour. See one PR up for a CLI that i used to verify the trailing new line behaviour
* Add a formatter CLI for debugging
This adds a ruff_python_formatter cli modelled aber `rustfmt` that i use for debugging
* clippy
* Add print IR and print comments options
Tested with `cargo run --bin ruff_python_formatter -- --print-ir --print-comments scratch.py`
* Abstract codegen with stylist into a CodegenStylist trait
Replace all duplicate invocations of
```rust
let mut state = CodegenState {
default_newline: &stylist.line_ending(),
default_indent: stylist.indentation(),
..CodegenState::default()
}
tree.codegen(&mut state);
state.to_string()
```
with
```rust
tree.codegen_stylist(&stylist);
```
No functional changes.
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## Summary
And more custom logic around comments in bodies... uff.
Let's say we have the following code
```python
if x == y:
pass # trailing comment of pass
else: # trailing comment of `else`
print("I have no comments")
```
Right now, the formatter attaches the `# trailing comment of `else` as a trailing comment of `pass` because it doesn't "see" that there's an `else` keyword in between (because the else body is just a Vec and not a node).
This PR adds custom logic that attaches the trailing comments after the `else` as dangling comments to the `if` statement. The if statement must then split the dangling comments by `comments.text_position()`:
* All comments up to the first end-of-line comment are leading comments of the `else` keyword.
* All end-of-line comments coming after are `trailing` comments for the `else` keyword.
## Test Plan
I added new unit tests.
### Summary
This PR adds custom logic to handle end-of-line comments of the last statement in a body.
For example:
```python
while True:
if something.changed:
do.stuff() # trailing comment
b
```
The `# trailing comment` is a trailing comment of the `do.stuff()` expression statement. We incorrectly attached the comment as a trailing comment of the enclosing `while` statement because the comment is between the end of the while statement (the `while` statement ends right after `do.stuff()`) and before the `b` statement.
This PR fixes the placement to correctly attach these comments to the last statement in a body (recursively).
## Test Plan
I reviewed the snapshots and they now look correct. This may appear odd because a lot comments have now disappeared. This is the expected result because we use `verbatim` formatting for the block statements (like `while`) and that means that it only formats the inner content of the block, but not any trailing comments. The comments were visible before, because they were associated with the block statement (e.g. `while`).
