Insert space to avoid syntax error in RSE fixes (#6886)

Closes #6810.
astral-sh · Aug 25, 2023 · 2883ae4 · 2883ae4
1 parent bd625b1
commit 2883ae4
Show file tree

Hide file tree

Showing 3 changed files with 106 additions and 1 deletion.
diff --git a/crates/ruff/resources/test/fixtures/flake8_raise/RSE102.py b/crates/ruff/resources/test/fixtures/flake8_raise/RSE102.py
@@ -68,3 +68,14 @@ def error():
 
 # OK
 raise ctypes.WinError(1)
+
+
+# RSE102
+raise IndexError()from ZeroDivisionError
+
+raise IndexError()\
+from ZeroDivisionError
+
+raise IndexError() from ZeroDivisionError
+
+raise IndexError();
diff --git a/crates/ruff/src/rules/flake8_raise/rules/unnecessary_paren_on_raise_exception.rs b/crates/ruff/src/rules/flake8_raise/rules/unnecessary_paren_on_raise_exception.rs
@@ -74,7 +74,25 @@ pub(crate) fn unnecessary_paren_on_raise_exception(checker: &mut Checker, expr:
 
         let mut diagnostic = Diagnostic::new(UnnecessaryParenOnRaiseException, arguments.range());
         if checker.patch(diagnostic.kind.rule()) {
-            diagnostic.set_fix(Fix::automatic(Edit::range_deletion(arguments.range())));
+            // If the arguments are immediately followed by a `from`, insert whitespace to avoid
+            // a syntax error, as in:
+            // ```python
+            // raise IndexError()from ZeroDivisionError
+            // ```
+            if checker
+                .locator()
+                .after(arguments.end())
+                .chars()
+                .next()
+                .is_some_and(char::is_alphanumeric)
+            {
+                diagnostic.set_fix(Fix::automatic(Edit::range_replacement(
+                    " ".to_string(),
+                    arguments.range(),
+                )));
+            } else {
+                diagnostic.set_fix(Fix::automatic(Edit::range_deletion(arguments.range())));
+            }
         }
         checker.diagnostics.push(diagnostic);
     }

diff --git a/...ots/ruff__rules__flake8_raise__tests__unnecessary-paren-on-raise-exception_RSE102.py.snap b/...ots/ruff__rules__flake8_raise__tests__unnecessary-paren-on-raise-exception_RSE102.py.snap
@@ -179,4 +179,80 @@ RSE102.py:37:16: RSE102 [*] Unnecessary parentheses on raised exception
 41 39 | # OK
 42 40 | raise AssertionError
 
+RSE102.py:74:17: RSE102 [*] Unnecessary parentheses on raised exception
+   |
+73 | # RSE102
+74 | raise IndexError()from ZeroDivisionError
+   |                 ^^ RSE102
+75 | 
+76 | raise IndexError()\
+   |
+   = help: Remove unnecessary parentheses
+
+ℹ Fix
+71 71 | 
+72 72 | 
+73 73 | # RSE102
+74    |-raise IndexError()from ZeroDivisionError
+   74 |+raise IndexError from ZeroDivisionError
+75 75 | 
+76 76 | raise IndexError()\
+77 77 | from ZeroDivisionError
+
+RSE102.py:76:17: RSE102 [*] Unnecessary parentheses on raised exception
+   |
+74 | raise IndexError()from ZeroDivisionError
+75 | 
+76 | raise IndexError()\
+   |                 ^^ RSE102
+77 | from ZeroDivisionError
+   |
+   = help: Remove unnecessary parentheses
+
+ℹ Fix
+73 73 | # RSE102
+74 74 | raise IndexError()from ZeroDivisionError
+75 75 | 
+76    |-raise IndexError()\
+   76 |+raise IndexError\
+77 77 | from ZeroDivisionError
+78 78 | 
+79 79 | raise IndexError() from ZeroDivisionError
+
+RSE102.py:79:17: RSE102 [*] Unnecessary parentheses on raised exception
+   |
+77 | from ZeroDivisionError
+78 | 
+79 | raise IndexError() from ZeroDivisionError
+   |                 ^^ RSE102
+80 | 
+81 | raise IndexError();
+   |
+   = help: Remove unnecessary parentheses
+
+ℹ Fix
+76 76 | raise IndexError()\
+77 77 | from ZeroDivisionError
+78 78 | 
+79    |-raise IndexError() from ZeroDivisionError
+   79 |+raise IndexError from ZeroDivisionError
+80 80 | 
+81 81 | raise IndexError();
+
+RSE102.py:81:17: RSE102 [*] Unnecessary parentheses on raised exception
+   |
+79 | raise IndexError() from ZeroDivisionError
+80 | 
+81 | raise IndexError();
+   |                 ^^ RSE102
+   |
+   = help: Remove unnecessary parentheses
+
+ℹ Fix
+78 78 | 
+79 79 | raise IndexError() from ZeroDivisionError
+80 80 | 
+81    |-raise IndexError();
+   81 |+raise IndexError;
+