Insert required space when fixing B013

crates/ruff/resources/test/fixtures/flake8_bugbear/B013.py

@@ -10,3 +10,5 @@
     pass
 except (*retriable_exceptions,):
     pass
+except(ValueError,):
+    pass

crates/ruff/src/rules/flake8_bugbear/rules/redundant_tuple_in_exception_handler.rs

@@ -3,7 +3,7 @@ use ruff_python_ast::{self as ast, ExceptHandler, Expr};
 use ruff_diagnostics::{AlwaysAutofixableViolation, Diagnostic, Edit, Fix};
 use ruff_macros::{derive_message_formats, violation};
 use ruff_python_ast::helpers::map_starred;
-use ruff_text_size::Ranged;
+use ruff_text_size::{Ranged, TextRange};
 
 use crate::checkers::ast::Checker;
 use crate::registry::AsRule;
@@ -78,8 +78,26 @@ pub(crate) fn redundant_tuple_in_exception_handler(
             type_.range(),
         );
         if checker.patch(diagnostic.kind.rule()) {
+            // If there's no space between the `except` and the tuple, we need to insert a space,
+            // as in:
+            // ```python
+            // except(ValueError,):
+            // ```
+            // Otherwise, the output will be invalid syntax, since we're removing a set of
+            // parentheses.
+            let requires_space = checker
+                .locator()
+                .slice(TextRange::up_to(type_.start()))
+                .chars()
+                .last()
+                .is_some_and(|char| char.is_ascii_alphabetic());
+            let content = checker.generator().expr(elt);
             diagnostic.set_fix(Fix::automatic(Edit::range_replacement(
-                checker.generator().expr(elt),
+                if requires_space {
+                    format!(" {content}")
+                } else {
+                    content
+                },
                 type_.range(),
             )));
         }

crates/ruff/src/rules/flake8_bugbear/snapshots/ruff__rules__flake8_bugbear__tests__B013_B013.py.snap

@@ -29,6 +29,7 @@ B013.py:11:8: B013 [*] A length-one tuple literal is redundant in exception hand
 11 | except (*retriable_exceptions,):
    |        ^^^^^^^^^^^^^^^^^^^^^^^^ B013
 12 |     pass
+13 | except(ValueError,):
    |
    = help: Replace with `except retriable_exceptions`
 
@@ -39,5 +40,25 @@ B013.py:11:8: B013 [*] A length-one tuple literal is redundant in exception hand
 11    |-except (*retriable_exceptions,):
    11 |+except retriable_exceptions:
 12 12 |     pass
+13 13 | except(ValueError,):
+14 14 |     pass
+
+B013.py:13:7: B013 [*] A length-one tuple literal is redundant in exception handlers
+   |
+11 | except (*retriable_exceptions,):
+12 |     pass
+13 | except(ValueError,):
+   |       ^^^^^^^^^^^^^ B013
+14 |     pass
+   |
+   = help: Replace with `except ValueError`
+
+ℹ Fix
+10 10 |     pass
+11 11 | except (*retriable_exceptions,):
+12 12 |     pass
+13    |-except(ValueError,):
+   13 |+except ValueError:
+14 14 |     pass