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## Summary
This PR replaces the `verbatim_text` builder with a `not_yet_implemented` builder that emits `NOT_YET_IMPLEMENTED_<NodeKind>` for not yet implemented nodes.
The motivation for this change is that partially formatting compound statements can result in incorrectly indented code, which is a syntax error:
```python
def func_no_args():
a; b; c
if True: raise RuntimeError
if False: ...
for i in range(10):
print(i)
continue
```
Get's reformatted to
```python
def func_no_args():
a; b; c
if True: raise RuntimeError
if False: ...
for i in range(10):
print(i)
continue
```
because our formatter does not yet support `for` statements and just inserts the text from the source.
## Downsides
Using an identifier will not work in all situations. For example, an identifier is invalid in an `Arguments ` position. That's why I kept `verbatim_text` around and e.g. use it in the `Arguments` formatting logic where incorrect indentations are impossible (to my knowledge). Meaning, `verbatim_text` we can opt in to `verbatim_text` when we want to iterate quickly on nodes that we don't want to provide a full implementation yet and using an identifier would be invalid.
## Upsides
Running this on main discovered stability issues with the newline handling that were previously "hidden" because of the verbatim formatting. I guess that's an upside :)
## Test Plan
None?
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## Summary
This issue fixes the removal of empty lines between a leading comment and the previous statement:
```python
a = 20
# leading comment
b = 10
```
Ruff removed the empty line between `a` and `b` because:
* The leading comments formatting does not preserve leading newlines (to avoid adding new lines at the top of a body)
* The `JoinNodesBuilder` counted the lines before `b`, which is 1 -> Doesn't insert a new line
This is fixed by changing the `JoinNodesBuilder` to count the lines instead *after* the last node. This correctly gives 1, and the `# leading comment` will insert the empty lines between any other leading comment or the node.
## Test Plan
I added a new test for empty lines.
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.
