[flake8-logging] Implement LOG001: direct-logger-instantiation

crates/ruff/resources/test/fixtures/flake8_logging/LOG001.py

@@ -0,0 +1,5 @@
+import logging
+
+logging.Logger(__name__)
+logging.Logger()
+logging.getLogger(__name__)

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

@@ -892,6 +892,9 @@ pub(crate) fn expression(expr: &Expr, checker: &mut Checker) {
             if checker.enabled(Rule::QuadraticListSummation) {
                 ruff::rules::quadratic_list_summation(checker, call);
             }
+            if checker.enabled(Rule::DirectLoggerInstantiation) {
+                flake8_logging::rules::direct_logger_instantiation(checker, call);
+            }
         }
         Expr::Dict(ast::ExprDict {
             keys,

crates/ruff/src/codes.rs

@@ -921,6 +921,7 @@ pub fn code_to_rule(linter: Linter, code: &str) -> Option<(RuleGroup, Rule)> {
         (Refurb, "145") => (RuleGroup::Preview, rules::refurb::rules::SliceCopy),
 
         // flake8-logging
+        (Flake8Logging, "001") => (RuleGroup::Preview, rules::flake8_logging::rules::DirectLoggerInstantiation),
         (Flake8Logging, "009") => (RuleGroup::Preview, rules::flake8_logging::rules::UndocumentedWarn),
 
         _ => return None,

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

@@ -70,6 +70,7 @@ impl Violation for MutableArgumentDefault {
     fn message(&self) -> String {
         format!("Do not use mutable data structures for argument defaults")
     }
+
     fn autofix_title(&self) -> Option<String> {
         Some(format!("Replace with `None`; initialize within function"))
     }

crates/ruff/src/rules/flake8_logging/mod.rs

@@ -13,6 +13,7 @@ mod tests {
     use crate::settings::Settings;
     use crate::test::test_path;
 
+    #[test_case(Rule::DirectLoggerInstantiation, Path::new("LOG001.py"))]
     #[test_case(Rule::UndocumentedWarn, Path::new("LOG009.py"))]
     fn rules(rule_code: Rule, path: &Path) -> Result<()> {
         let snapshot = format!("{}_{}", rule_code.noqa_code(), path.to_string_lossy());

crates/ruff/src/rules/flake8_logging/rules/direct_logger_instantiation.rs

@@ -0,0 +1,77 @@
+use ruff_diagnostics::{AutofixKind, Diagnostic, Edit, Fix, Violation};
+use ruff_macros::{derive_message_formats, violation};
+use ruff_python_ast as ast;
+use ruff_text_size::Ranged;
+
+use crate::checkers::ast::Checker;
+use crate::importer::ImportRequest;
+use crate::registry::AsRule;
+
+/// ## What it does
+/// Checks for direct instantiation of `logging.Logger`, as opposed to using
+/// `logging.getLogger()`.
+///
+/// ## Why is this bad?
+/// The [Logger Objects] documentation states that:
+///
+/// > Note that Loggers should NEVER be instantiated directly, but always
+/// > through the module-level function `logging.getLogger(name)`.
+///
+/// If a logger is directly instantiated, it won't be added to the logger
+/// tree, and will bypass all configuration. Messages logged to it will
+/// only be sent to the "handler of last resort", skipping any filtering
+/// or formatting.
+///
+/// ## Example
+/// ```python
+/// import logging
+///
+/// logger = logging.Logger(__name__)
+/// ```
+///
+/// Use instead:
+/// ```python
+/// import logging
+///
+/// logger = logging.getLogger(__name__)
+/// ```
+///
+/// [Logger Objects]: https://docs.python.org/3/library/logging.html#logger-objects
+#[violation]
+pub struct DirectLoggerInstantiation;
+
+impl Violation for DirectLoggerInstantiation {
+    const AUTOFIX: AutofixKind = AutofixKind::Sometimes;
+
+    #[derive_message_formats]
+    fn message(&self) -> String {
+        format!("Use `logging.getLogger()` to instantiate loggers")
+    }
+
+    fn autofix_title(&self) -> Option<String> {
+        Some(format!("Replace with `logging.getLogger()`"))
+    }
+}
+
+/// LOG001
+pub(crate) fn direct_logger_instantiation(checker: &mut Checker, call: &ast::ExprCall) {
+    if checker
+        .semantic()
+        .resolve_call_path(call.func.as_ref())
+        .is_some_and(|call_path| matches!(call_path.as_slice(), ["logging", "Logger"]))
+    {
+        let mut diagnostic = Diagnostic::new(DirectLoggerInstantiation, call.func.range());
+        if checker.patch(diagnostic.kind.rule()) {
+            diagnostic.try_set_fix(|| {
+                let (import_edit, binding) = checker.importer().get_or_import_symbol(
+                    &ImportRequest::import("logging", "getLogger"),
+                    call.func.start(),
+                    checker.semantic(),
+                )?;
+                let reference_edit = Edit::range_replacement(binding, call.func.range());
+                Ok(Fix::suggested_edits(import_edit, [reference_edit]))
+            });
+        }
+        checker.diagnostics.push(diagnostic);
+    }
+}

crates/ruff/src/rules/flake8_logging/rules/mod.rs

@@ -1,3 +1,5 @@
+pub(crate) use direct_logger_instantiation::*;
 pub(crate) use undocumented_warn::*;
 
+mod direct_logger_instantiation;
 mod undocumented_warn;

crates/ruff/src/rules/flake8_logging/rules/undocumented_warn.rs

@@ -59,7 +59,7 @@ pub(crate) fn undocumented_warn(checker: &mut Checker, expr: &Expr) {
             diagnostic.try_set_fix(|| {
                 let (import_edit, binding) = checker.importer().get_or_import_symbol(
                     &ImportRequest::import("logging", "WARNING"),
-                    expr.range().start(),
+                    expr.start(),
                     checker.semantic(),
                 )?;
                 let reference_edit = Edit::range_replacement(binding, expr.range());

crates/ruff/src/rules/flake8_logging/snapshots/ruff__rules__flake8_logging__tests__LOG001_LOG001.py.snap

@@ -0,0 +1,40 @@
+---
+source: crates/ruff/src/rules/flake8_logging/mod.rs
+---
+LOG001.py:3:1: LOG001 [*] Use `logging.getLogger()` to instantiate loggers
+  |
+1 | import logging
+2 | 
+3 | logging.Logger(__name__)
+  | ^^^^^^^^^^^^^^ LOG001
+4 | logging.Logger()
+5 | logging.getLogger(__name__)
+  |
+  = help: Replace with `logging.getLogger()`
+
+ℹ Suggested fix
+1 1 | import logging
+2 2 | 
+3   |-logging.Logger(__name__)
+  3 |+logging.getLogger(__name__)
+4 4 | logging.Logger()
+5 5 | logging.getLogger(__name__)
+
+LOG001.py:4:1: LOG001 [*] Use `logging.getLogger()` to instantiate loggers
+  |
+3 | logging.Logger(__name__)
+4 | logging.Logger()
+  | ^^^^^^^^^^^^^^ LOG001
+5 | logging.getLogger(__name__)
+  |
+  = help: Replace with `logging.getLogger()`
+
+ℹ Suggested fix
+1 1 | import logging
+2 2 | 
+3 3 | logging.Logger(__name__)
+4   |-logging.Logger()
+  4 |+logging.getLogger()
+5 5 | logging.getLogger(__name__)
+
+

crates/ruff_workspace/src/configuration.rs

@@ -853,9 +853,11 @@ mod tests {
     ];
 
     const PREVIEW_RULES: &[Rule] = &[
+        Rule::DirectLoggerInstantiation,
         Rule::ManualDictComprehension,
-        Rule::TooManyPublicMethods,
         Rule::SliceCopy,
+        Rule::TooManyPublicMethods,
+        Rule::TooManyPublicMethods,
         Rule::UndocumentedWarn,
     ];