[refurb] Implement repeated-append rule (FURB113)

crates/ruff/resources/test/fixtures/refurb/FURB113.py

@@ -0,0 +1,169 @@
+from typing import List
+
+
+def func():
+    pass
+
+
+nums = []
+nums2 = []
+nums3: list[int] = func()
+nums4: List[int]
+
+
+class C:
+    def append(self, x):
+        pass
+
+
+# Errors.
+
+
+# FURB113
+nums.append(1)
+nums.append(2)
+pass
+
+
+# FURB113
+nums3.append(1)
+nums3.append(2)
+pass
+
+
+# FURB113
+nums4.append(1)
+nums4.append(2)
+pass
+
+
+# FURB113
+nums.append(1)
+nums2.append(1)
+nums.append(2)
+nums.append(3)
+pass
+
+
+# FURB113
+nums.append(1)
+nums2.append(1)
+nums.append(2)
+# FURB113
+nums3.append(1)
+nums.append(3)
+# FURB113
+nums4.append(1)
+nums4.append(2)
+nums3.append(2)
+pass
+
+# FURB113
+nums.append(1)
+nums.append(2)
+nums.append(3)
+
+
+if True:
+    # FURB113
+    nums.append(1)
+    nums.append(2)
+
+
+if True:
+    # FURB113
+    nums.append(1)
+    nums.append(2)
+    pass
+
+
+if True:
+    # FURB113
+    nums.append(1)
+    nums2.append(1)
+    nums.append(2)
+    nums.append(3)
+
+
+def yes_one(x: list[int]):
+    # FURB113
+    x.append(1)
+    x.append(2)
+
+
+def yes_two(x: List[int]):
+    # FURB113
+    x.append(1)
+    x.append(2)
+
+
+def yes_three(*, x: list[int]):
+    # FURB113
+    x.append(1)
+    x.append(2)
+
+
+def yes_four(x: list[int], /):
+    # FURB113
+    x.append(1)
+    x.append(2)
+
+
+def yes_five(x: list[int], y: list[int]):
+    # FURB113
+    x.append(1)
+    x.append(2)
+    y.append(1)
+    x.append(3)
+
+
+def yes_six(x: list):
+    # FURB113
+    x.append(1)
+    x.append(2)
+
+
+# Non-errors.
+
+nums.append(1)
+pass
+nums.append(2)
+
+
+if True:
+    nums.append(1)
+    pass
+    nums.append(2)
+
+
+nums.append(1)
+pass
+
+
+nums.append(1)
+nums2.append(2)
+
+
+nums.copy()
+nums.copy()
+
+
+c = C()
+c.append(1)
+c.append(2)
+
+
+def not_one(x):
+    x.append(1)
+    x.append(2)
+
+
+def not_two(x: C):
+    x.append(1)
+    x.append(2)
+
+
+# redefining a list variable with a new type shouldn't confuse ruff.
+nums2 = C()
+nums2.append(1)
+nums2.append(2)

crates/ruff/src/checkers/ast/analyze/statement.rs

@@ -13,7 +13,7 @@ use crate::rules::{
     flake8_django, flake8_errmsg, flake8_import_conventions, flake8_pie, flake8_pyi,
     flake8_pytest_style, flake8_raise, flake8_return, flake8_simplify, flake8_slots,
     flake8_tidy_imports, flake8_type_checking, mccabe, pandas_vet, pep8_naming, perflint,
-    pycodestyle, pyflakes, pygrep_hooks, pylint, pyupgrade, ruff, tryceratops,
+    pycodestyle, pyflakes, pygrep_hooks, pylint, pyupgrade, refurb, ruff, tryceratops,
 };
 use crate::settings::types::PythonVersion;
 
@@ -1484,6 +1484,9 @@ pub(crate) fn statement(stmt: &Stmt, checker: &mut Checker) {
             if checker.enabled(Rule::AsyncioDanglingTask) {
                 ruff::rules::asyncio_dangling_task(checker, value);
             }
+            if checker.enabled(Rule::RepeatedAppend) {
+                refurb::rules::repeated_append(checker, stmt);
+            }
         }
         _ => {}
     }

crates/ruff/src/codes.rs

@@ -865,6 +865,9 @@ pub fn code_to_rule(linter: Linter, code: &str) -> Option<(RuleGroup, Rule)> {
         (Flake8Slots, "001") => (RuleGroup::Unspecified, rules::flake8_slots::rules::NoSlotsInTupleSubclass),
         (Flake8Slots, "002") => (RuleGroup::Unspecified, rules::flake8_slots::rules::NoSlotsInNamedtupleSubclass),
 
+        // refurb
+        (Refurb, "113") => (RuleGroup::Nursery, rules::refurb::rules::RepeatedAppend),
+
         _ => return None,
     })
 }

crates/ruff/src/registry.rs

@@ -196,6 +196,9 @@ pub enum Linter {
     /// [Perflint](https://pypi.org/project/perflint/)
     #[prefix = "PERF"]
     Perflint,
+    /// [refurb](https://pypi.org/project/refurb/)
+    #[prefix = "FURB"]
+    Refurb,
     /// Ruff-specific rules
     #[prefix = "RUF"]
     Ruff,

crates/ruff/src/rules/mod.rs

@@ -52,5 +52,6 @@ pub mod pyflakes;
 pub mod pygrep_hooks;
 pub mod pylint;
 pub mod pyupgrade;
+pub mod refurb;
 pub mod ruff;
 pub mod tryceratops;

crates/ruff/src/rules/refurb/mod.rs

@@ -0,0 +1,25 @@
+//! Rules from [refurb](https://pypi.org/project/refurb/)/
+pub(crate) mod rules;
+
+#[cfg(test)]
+mod tests {
+    use std::path::Path;
+
+    use anyhow::Result;
+    use test_case::test_case;
+
+    use crate::registry::Rule;
+    use crate::test::test_path;
+    use crate::{assert_messages, settings};
+
+    #[test_case(Rule::RepeatedAppend, Path::new("FURB113.py"))]
+    fn rules(rule_code: Rule, path: &Path) -> Result<()> {
+        let snapshot = format!("{}_{}", rule_code.noqa_code(), path.to_string_lossy());
+        let diagnostics = test_path(
+            Path::new("refurb").join(path).as_path(),
+            &settings::Settings::for_rule(rule_code),
+        )?;
+        assert_messages!(snapshot, diagnostics);
+        Ok(())
+    }
+}

crates/ruff/src/rules/refurb/rules/mod.rs

@@ -0,0 +1,3 @@
+pub(crate) use repeated_append::*;
+
+mod repeated_append;