feat: implement TRY301 (#2113)

README.md

@@ -1203,6 +1203,7 @@ For more, see [tryceratops](https://pypi.org/project/tryceratops/1.1.0/) on PyPI
 | TRY200 | reraise-no-cause | Use `raise from` to specify exception cause |  |
 | TRY201 | verbose-raise | Use `raise` without specifying exception name |  |
 | TRY300 | try-consider-else | Consider `else` block |  |
+| TRY301 | raise-within-try | Abstract `raise` to an inner function |  |
 
 ### flake8-use-pathlib (PTH)
 

resources/test/fixtures/tryceratops/TRY301.py

@@ -0,0 +1,29 @@
+class MyException(Exception):
+    pass
+
+
+def bad():
+    try:
+        a = process()
+        if not a:
+            raise MyException(a)
+
+        raise MyException(a)
+
+        try:
+            b = process()
+            if not b:
+                raise MyException(b)
+        except Exception:
+            logger.exception("something failed")
+    except Exception:
+        logger.exception("something failed")
+
+
+def good():
+    try:
+        a = process()  # This throws the exception now
+    except MyException:
+        logger.exception("a failed")
+    except Exception:
+        logger.exception("something failed")

ruff.schema.json

@@ -1818,6 +1818,7 @@
         "TRY3",
         "TRY30",
         "TRY300",
+        "TRY301",
         "TYP",
         "TYP0",
         "TYP00",

src/checkers/ast.rs

@@ -1582,6 +1582,9 @@ where
                 if self.settings.rules.enabled(&Rule::VerboseRaise) {
                     tryceratops::rules::verbose_raise(self, handlers);
                 }
+                if self.settings.rules.enabled(&Rule::RaiseWithinTry) {
+                    tryceratops::rules::raise_within_try(self, body);
+                }
             }
             StmtKind::Assign { targets, value, .. } => {
                 if self.settings.rules.enabled(&Rule::DoNotAssignLambda) {

src/registry.rs

@@ -434,6 +434,7 @@ ruff_macros::define_rule_mapping!(
     TRY200 => rules::tryceratops::rules::ReraiseNoCause,
     TRY201 => rules::tryceratops::rules::VerboseRaise,
     TRY300 => rules::tryceratops::rules::TryConsiderElse,
+    TRY301 => rules::tryceratops::rules::RaiseWithinTry,
     // flake8-use-pathlib
     PTH100 => rules::flake8_use_pathlib::violations::PathlibAbspath,
     PTH101 => rules::flake8_use_pathlib::violations::PathlibChmod,

src/rules/tryceratops/mod.rs

@@ -17,6 +17,7 @@ mod tests {
     #[test_case(Rule::ReraiseNoCause, Path::new("TRY200.py"); "TRY200")]
     #[test_case(Rule::VerboseRaise, Path::new("TRY201.py"); "TRY201")]
     #[test_case(Rule::TryConsiderElse, Path::new("TRY300.py"); "TRY300")]
+    #[test_case(Rule::RaiseWithinTry , Path::new("TRY301.py"); "TRY301")]
     fn rules(rule_code: Rule, path: &Path) -> Result<()> {
         let snapshot = format!("{}_{}", rule_code.as_ref(), path.to_string_lossy());
         let diagnostics = test_path(

src/rules/tryceratops/rules/mod.rs

@@ -1,9 +1,11 @@
 pub use prefer_type_error::{prefer_type_error, PreferTypeError};
+pub use raise_within_try::{raise_within_try, RaiseWithinTry};
 pub use reraise_no_cause::{reraise_no_cause, ReraiseNoCause};
 pub use try_consider_else::{try_consider_else, TryConsiderElse};
 pub use verbose_raise::{verbose_raise, VerboseRaise};
 
 mod prefer_type_error;
+mod raise_within_try;
 mod reraise_no_cause;
 mod try_consider_else;
 mod verbose_raise;

src/rules/tryceratops/rules/raise_within_try.rs

@@ -0,0 +1,54 @@
+use ruff_macros::derive_message_formats;
+use rustpython_ast::{Stmt, StmtKind};
+
+use crate::ast::types::Range;
+use crate::ast::visitor::{self, Visitor};
+use crate::checkers::ast::Checker;
+use crate::define_violation;
+use crate::registry::Diagnostic;
+use crate::violation::Violation;
+
+define_violation!(
+    pub struct RaiseWithinTry;
+);
+impl Violation for RaiseWithinTry {
+    #[derive_message_formats]
+    fn message(&self) -> String {
+        format!("Abstract `raise` to an inner function")
+    }
+}
+
+#[derive(Default)]
+struct RaiseStatementVisitor<'a> {
+    raises: Vec<&'a Stmt>,
+}
+
+impl<'a, 'b> Visitor<'b> for RaiseStatementVisitor<'a>
+where
+    'b: 'a,
+{
+    fn visit_stmt(&mut self, stmt: &'b Stmt) {
+        match stmt.node {
+            StmtKind::Raise { .. } => self.raises.push(stmt),
+            StmtKind::Try { .. } => (),
+            _ => visitor::walk_stmt(self, stmt),
+        }
+    }
+}
+
+/// TRY301
+pub fn raise_within_try(checker: &mut Checker, body: &[Stmt]) {
+    let raises = {
+        let mut visitor = RaiseStatementVisitor::default();
+        for stmt in body {
+            visitor.visit_stmt(stmt);
+        }
+        visitor.raises
+    };
+
+    for stmt in raises {
+        checker
+            .diagnostics
+            .push(Diagnostic::new(RaiseWithinTry, Range::from_located(stmt)));
+    }
+}

src/rules/tryceratops/snapshots/ruff__rules__tryceratops__tests__raise-within-try_TRY301.py.snap

@@ -0,0 +1,35 @@
+---
+source: src/rules/tryceratops/mod.rs
+expression: diagnostics
+---
+- kind:
+    RaiseWithinTry: ~
+  location:
+    row: 9
+    column: 12
+  end_location:
+    row: 9
+    column: 32
+  fix: ~
+  parent: ~
+- kind:
+    RaiseWithinTry: ~
+  location:
+    row: 11
+    column: 8
+  end_location:
+    row: 11
+    column: 28
+  fix: ~
+  parent: ~
+- kind:
+    RaiseWithinTry: ~
+  location:
+    row: 16
+    column: 16
+  end_location:
+    row: 16
+    column: 36
+  fix: ~
+  parent: ~
+