ruff/crates/ruff_linter/resources
Dylan a876090715
[internal] Return statements in finally block point to end block for unreachable (PLW0101) (#15276)
Note: `PLW0101` remains in testing rather than preview, so this PR does
not modify any public behavior (hence the title beginning with
`internal` rather than `pylint`, for the sake of the changelog.)

Fixes an error in the processing of `try` statements in the control flow
graph builder.

When processing a try statement, the block following a `return` was
forced to point to the `finally` block. However, if the return was _in_
the `finally` block, this caused the block to point to itself. In the
case where the whole `try-finally` statement was also included inside of
a loop, this caused an infinite loop in the builder for the control flow
graph as it attempted to resolve edges.

Closes #15248

## Test function
### Source
```python
def l():
    while T:
        try:
            while ():
                if 3:
                    break
        finally:
            return
```

### Control Flow Graph
```mermaid
flowchart TD
  start(("Start"))
  return(("End"))
  block0[["`*(empty)*`"]]
  block1[["Loop continue"]]
  block2["return\n"]
  block3[["Loop continue"]]
  block4["break\n"]
  block5["if 3:
                    break\n"]
  block6["while ():
                if 3:
                    break\n"]
  block7[["Exception raised"]]
  block8["try:
            while ():
                if 3:
                    break
        finally:
            return\n"]
  block9["while T:
        try:
            while ():
                if 3:
                    break
        finally:
            return\n"]
  start --> block9
  block9 -- "T" --> block8
  block9 -- "else" --> block0
  block8 -- "Exception raised" --> block7
  block8 -- "else" --> block6
  block7 --> block2
  block6 -- "()" --> block5
  block6 -- "else" --> block2
  block5 -- "3" --> block4
  block5 -- "else" --> block3
  block4 --> block2
  block3 --> block6
  block2 --> return
  block1 --> block9
  block0 --> return
```
2025-01-07 11:26:04 -06:00
..
test [internal] Return statements in finally block point to end block for unreachable (PLW0101) (#15276) 2025-01-07 11:26:04 -06:00
__init__.py [pylint] (Re-)Implement import-private-name (C2701) (#9553) 2024-01-16 14:03:11 -05:00