[flake8-simplify] Add autofix for contextlib.suppress (SIM105) (#3915)

crates/ruff/src/rules/flake8_simplify/rules/suppressible_exception.rs

@@ -1,36 +1,44 @@
-use rustpython_parser::ast::{Excepthandler, ExcepthandlerKind, Located, Stmt, StmtKind};
+use rustpython_parser::ast::{Excepthandler, ExcepthandlerKind, Located, Location, Stmt, StmtKind};
 
-use ruff_diagnostics::{Diagnostic, Violation};
+use ruff_diagnostics::{AlwaysAutofixableViolation, Diagnostic, Edit, Fix};
 use ruff_macros::{derive_message_formats, violation};
 use ruff_python_ast::call_path::compose_call_path;
 use ruff_python_ast::helpers;
 use ruff_python_ast::types::Range;
 
+use crate::autofix::actions::get_or_import_symbol;
 use crate::checkers::ast::Checker;
+use crate::registry::AsRule;
 
 #[violation]
 pub struct SuppressibleException {
     pub exception: String,
 }
 
-impl Violation for SuppressibleException {
+impl AlwaysAutofixableViolation for SuppressibleException {
     #[derive_message_formats]
     fn message(&self) -> String {
         let SuppressibleException { exception } = self;
-        format!("Use `contextlib.suppress({exception})` instead of try-except-pass")
+        format!("Use `contextlib.suppress({exception})` instead of `try`-`except`-`pass`")
+    }
+
+    fn autofix_title(&self) -> String {
+        let SuppressibleException { exception } = self;
+        format!("Replace with `contextlib.suppress({exception})`")
     }
 }
+
 /// SIM105
 pub fn suppressible_exception(
     checker: &mut Checker,
     stmt: &Stmt,
-    body: &[Stmt],
+    try_body: &[Stmt],
     handlers: &[Excepthandler],
     orelse: &[Stmt],
     finalbody: &[Stmt],
 ) {
     if !matches!(
-        body,
+        try_body,
         [Located {
             node: StmtKind::Delete { .. }
                 | StmtKind::Assign { .. }
@@ -62,10 +70,36 @@ pub fn suppressible_exception(
             } else {
                 handler_names.join(", ")
             };
-            checker.diagnostics.push(Diagnostic::new(
+            let mut diagnostic = Diagnostic::new(
-                SuppressibleException { exception },
+                SuppressibleException {
+                    exception: exception.clone(),
+                },
                 Range::from(stmt),
-            ));
+            );
+
+            if checker.patch(diagnostic.kind.rule()) {
+                diagnostic.try_set_fix(|| {
+                    let (import_edit, binding) = get_or_import_symbol(
+                        "contextlib",
+                        "suppress",
+                        &checker.ctx,
+                        &checker.importer,
+                        checker.locator,
+                    )?;
+                    let try_ending = stmt.location.with_col_offset(3); // size of "try"
+                    let replace_try = Edit::replacement(
+                        format!("with {binding}({exception})"),
+                        stmt.location,
+                        try_ending,
+                    );
+                    let handler_line_begin = Location::new(handler.location.row(), 0);
+                    let remove_handler =
+                        Edit::deletion(handler_line_begin, handler.end_location.unwrap());
+                    Ok(Fix::from_iter([import_edit, replace_try, remove_handler]))
+                });
+            }
+
+            checker.diagnostics.push(diagnostic);
         }
     }
 }

crates/ruff/src/rules/flake8_simplify/snapshots/ruff__rules__flake8_simplify__tests__SIM105_SIM105.py.snap

@@ -4,9 +4,9 @@ expression: diagnostics
 ---
 - kind:
     name: SuppressibleException
-    body: "Use `contextlib.suppress(ValueError)` instead of try-except-pass"
+    body: "Use `contextlib.suppress(ValueError)` instead of `try`-`except`-`pass`"
-    suggestion: ~
+    suggestion: "Replace with `contextlib.suppress(ValueError)`"
-    fixable: false
+    fixable: true
   location:
     row: 4
     column: 0
@@ -14,13 +14,34 @@ expression: diagnostics
     row: 7
     column: 8
   fix:
-    edits: []
+    edits:
+      - content: "import contextlib\n"
+        location:
+          row: 1
+          column: 0
+        end_location:
+          row: 1
+          column: 0
+      - content: with contextlib.suppress(ValueError)
+        location:
+          row: 4
+          column: 0
+        end_location:
+          row: 4
+          column: 3
+      - content: ""
+        location:
+          row: 6
+          column: 0
+        end_location:
+          row: 7
+          column: 8
   parent: ~
 - kind:
     name: SuppressibleException
-    body: "Use `contextlib.suppress(ValueError, OSError)` instead of try-except-pass"
+    body: "Use `contextlib.suppress(ValueError, OSError)` instead of `try`-`except`-`pass`"
-    suggestion: ~
+    suggestion: "Replace with `contextlib.suppress(ValueError, OSError)`"
-    fixable: false
+    fixable: true
   location:
     row: 9
     column: 0
@@ -28,13 +49,34 @@ expression: diagnostics
     row: 12
     column: 8
   fix:
-    edits: []
+    edits:
+      - content: "import contextlib\n"
+        location:
+          row: 1
+          column: 0
+        end_location:
+          row: 1
+          column: 0
+      - content: "with contextlib.suppress(ValueError, OSError)"
+        location:
+          row: 9
+          column: 0
+        end_location:
+          row: 9
+          column: 3
+      - content: ""
+        location:
+          row: 11
+          column: 0
+        end_location:
+          row: 12
+          column: 8
   parent: ~
 - kind:
     name: SuppressibleException
-    body: "Use `contextlib.suppress(Exception)` instead of try-except-pass"
+    body: "Use `contextlib.suppress(Exception)` instead of `try`-`except`-`pass`"
-    suggestion: ~
+    suggestion: "Replace with `contextlib.suppress(Exception)`"
-    fixable: false
+    fixable: true
   location:
     row: 14
     column: 0
@@ -42,13 +84,34 @@ expression: diagnostics
     row: 17
     column: 8
   fix:
-    edits: []
+    edits:
+      - content: "import contextlib\n"
+        location:
+          row: 1
+          column: 0
+        end_location:
+          row: 1
+          column: 0
+      - content: with contextlib.suppress(Exception)
+        location:
+          row: 14
+          column: 0
+        end_location:
+          row: 14
+          column: 3
+      - content: ""
+        location:
+          row: 16
+          column: 0
+        end_location:
+          row: 17
+          column: 8
   parent: ~
 - kind:
     name: SuppressibleException
-    body: "Use `contextlib.suppress(a.Error, b.Error)` instead of try-except-pass"
+    body: "Use `contextlib.suppress(a.Error, b.Error)` instead of `try`-`except`-`pass`"
-    suggestion: ~
+    suggestion: "Replace with `contextlib.suppress(a.Error, b.Error)`"
-    fixable: false
+    fixable: true
   location:
     row: 19
     column: 0
@@ -56,6 +119,27 @@ expression: diagnostics
     row: 22
     column: 8
   fix:
-    edits: []
+    edits:
+      - content: "import contextlib\n"
+        location:
+          row: 1
+          column: 0
+        end_location:
+          row: 1
+          column: 0
+      - content: "with contextlib.suppress(a.Error, b.Error)"
+        location:
+          row: 19
+          column: 0
+        end_location:
+          row: 19
+          column: 3
+      - content: ""
+        location:
+          row: 21
+          column: 0
+        end_location:
+          row: 22
+          column: 8
   parent: ~