Add a rule to enforce lazy imports

crates/ruff/tests/cli/snapshots/cli__lint__requires_python_extend_from_shared_config.snap

@@ -182,6 +182,7 @@ linter.flake8_self.ignore_names = [
 linter.flake8_tidy_imports.ban_relative_imports = "parents"
 linter.flake8_tidy_imports.banned_api = {}
 linter.flake8_tidy_imports.banned_module_level_imports = []
+linter.flake8_tidy_imports.banned_eager_imports = []
 linter.flake8_type_checking.strict = false
 linter.flake8_type_checking.exempt_modules = [
 	typing,

crates/ruff/tests/cli/snapshots/cli__lint__requires_python_no_tool.snap

@@ -184,6 +184,7 @@ linter.flake8_self.ignore_names = [
 linter.flake8_tidy_imports.ban_relative_imports = "parents"
 linter.flake8_tidy_imports.banned_api = {}
 linter.flake8_tidy_imports.banned_module_level_imports = []
+linter.flake8_tidy_imports.banned_eager_imports = []
 linter.flake8_type_checking.strict = false
 linter.flake8_type_checking.exempt_modules = [
 	typing,

crates/ruff/tests/cli/snapshots/cli__lint__requires_python_no_tool_preview_enabled.snap

@@ -191,6 +191,7 @@ linter.flake8_self.ignore_names = [
 linter.flake8_tidy_imports.ban_relative_imports = "parents"
 linter.flake8_tidy_imports.banned_api = {}
 linter.flake8_tidy_imports.banned_module_level_imports = []
+linter.flake8_tidy_imports.banned_eager_imports = []
 linter.flake8_type_checking.strict = false
 linter.flake8_type_checking.exempt_modules = [
 	typing,

crates/ruff/tests/cli/snapshots/cli__lint__requires_python_no_tool_target_version_override.snap

@@ -186,6 +186,7 @@ linter.flake8_self.ignore_names = [
 linter.flake8_tidy_imports.ban_relative_imports = "parents"
 linter.flake8_tidy_imports.banned_api = {}
 linter.flake8_tidy_imports.banned_module_level_imports = []
+linter.flake8_tidy_imports.banned_eager_imports = []
 linter.flake8_type_checking.strict = false
 linter.flake8_type_checking.exempt_modules = [
 	typing,

crates/ruff/tests/cli/snapshots/cli__lint__requires_python_pyproject_toml_above.snap

@@ -183,6 +183,7 @@ linter.flake8_self.ignore_names = [
 linter.flake8_tidy_imports.ban_relative_imports = "parents"
 linter.flake8_tidy_imports.banned_api = {}
 linter.flake8_tidy_imports.banned_module_level_imports = []
+linter.flake8_tidy_imports.banned_eager_imports = []
 linter.flake8_type_checking.strict = false
 linter.flake8_type_checking.exempt_modules = [
 	typing,

crates/ruff/tests/cli/snapshots/cli__lint__requires_python_pyproject_toml_above_with_tool.snap

@@ -184,6 +184,7 @@ linter.flake8_self.ignore_names = [
 linter.flake8_tidy_imports.ban_relative_imports = "parents"
 linter.flake8_tidy_imports.banned_api = {}
 linter.flake8_tidy_imports.banned_module_level_imports = []
+linter.flake8_tidy_imports.banned_eager_imports = []
 linter.flake8_type_checking.strict = false
 linter.flake8_type_checking.exempt_modules = [
 	typing,

crates/ruff/tests/cli/snapshots/cli__lint__requires_python_ruff_toml_above-2.snap

@@ -182,6 +182,7 @@ linter.flake8_self.ignore_names = [
 linter.flake8_tidy_imports.ban_relative_imports = "parents"
 linter.flake8_tidy_imports.banned_api = {}
 linter.flake8_tidy_imports.banned_module_level_imports = []
+linter.flake8_tidy_imports.banned_eager_imports = []
 linter.flake8_type_checking.strict = false
 linter.flake8_type_checking.exempt_modules = [
 	typing,

crates/ruff/tests/cli/snapshots/cli__lint__requires_python_ruff_toml_above.snap

@@ -182,6 +182,7 @@ linter.flake8_self.ignore_names = [
 linter.flake8_tidy_imports.ban_relative_imports = "parents"
 linter.flake8_tidy_imports.banned_api = {}
 linter.flake8_tidy_imports.banned_module_level_imports = []
+linter.flake8_tidy_imports.banned_eager_imports = []
 linter.flake8_type_checking.strict = false
 linter.flake8_type_checking.exempt_modules = [
 	typing,

crates/ruff/tests/cli/snapshots/cli__lint__requires_python_ruff_toml_no_target_fallback.snap

@@ -182,6 +182,7 @@ linter.flake8_self.ignore_names = [
 linter.flake8_tidy_imports.ban_relative_imports = "parents"
 linter.flake8_tidy_imports.banned_api = {}
 linter.flake8_tidy_imports.banned_module_level_imports = []
+linter.flake8_tidy_imports.banned_eager_imports = []
 linter.flake8_type_checking.strict = false
 linter.flake8_type_checking.exempt_modules = [
 	typing,

crates/ruff/tests/snapshots/show_settings__display_default_settings.snap

@@ -295,6 +295,7 @@ linter.flake8_self.ignore_names = [
 linter.flake8_tidy_imports.ban_relative_imports = "parents"
 linter.flake8_tidy_imports.banned_api = {}
 linter.flake8_tidy_imports.banned_module_level_imports = []
+linter.flake8_tidy_imports.banned_eager_imports = []
 linter.flake8_type_checking.strict = false
 linter.flake8_type_checking.exempt_modules = [
 	typing,

crates/ruff/tests/snapshots/show_settings__display_settings_from_nested_directory.snap

@@ -303,6 +303,7 @@ linter.flake8_self.ignore_names = [
 linter.flake8_tidy_imports.ban_relative_imports = "parents"
 linter.flake8_tidy_imports.banned_api = {}
 linter.flake8_tidy_imports.banned_module_level_imports = []
+linter.flake8_tidy_imports.banned_eager_imports = []
 linter.flake8_type_checking.strict = false
 linter.flake8_type_checking.exempt_modules = [
 	typing,

crates/ruff_linter/resources/test/fixtures/flake8_tidy_imports/TID254.py

@@ -0,0 +1,28 @@
+from __future__ import annotations
+
+import os
+import typing as t
+lazy import pathlib
+
+from foo import bar
+lazy from foo import baz
+from starry import *
+
+with manager():
+    import email
+
+if True:
+    from bar import qux
+
+try:
+    import collections
+except Exception:
+    pass
+
+def func():
+    import fractions
+
+class Example:
+    import decimal
+
+x = 1; import pkg.submodule

crates/ruff_linter/resources/test/fixtures/flake8_tidy_imports/TID254_py314.py

@@ -0,0 +1,2 @@
+import os
+from foo import bar

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

@@ -582,6 +582,9 @@ pub(crate) fn statement(stmt: &Stmt, checker: &mut Checker) {
             if checker.is_rule_enabled(Rule::BannedModuleLevelImports) {
                 flake8_tidy_imports::rules::banned_module_level_imports(checker, stmt);
             }
+            if checker.is_rule_enabled(Rule::BannedEagerImports) {
+                flake8_tidy_imports::rules::banned_eager_imports(checker, stmt);
+            }
 
             for alias in names {
                 if checker.is_rule_enabled(Rule::NonAsciiImportName) {
@@ -786,6 +789,9 @@ pub(crate) fn statement(stmt: &Stmt, checker: &mut Checker) {
             if checker.is_rule_enabled(Rule::BannedModuleLevelImports) {
                 flake8_tidy_imports::rules::banned_module_level_imports(checker, stmt);
             }
+            if checker.is_rule_enabled(Rule::BannedEagerImports) {
+                flake8_tidy_imports::rules::banned_eager_imports(checker, stmt);
+            }
 
             if checker.is_rule_enabled(Rule::PytestIncorrectPytestImport) {
                 flake8_pytest_style::rules::import_from(checker, stmt, module, level);

crates/ruff_linter/src/checkers/ast/mod.rs

@@ -332,6 +332,29 @@ impl<'a> Checker<'a> {
         Generator::new(self.stylist.indentation(), self.stylist.line_ending())
     }
 
+    pub(crate) fn lazy_import_context(&self) -> Option<LazyImportContext> {
+        match self.semantic.current_scope().kind {
+            // Possible, but invalid positions.
+            ScopeKind::Function(_) => return Some(LazyImportContext::Function),
+            ScopeKind::Class(_) => return Some(LazyImportContext::Class),
+            // Valid position.
+            ScopeKind::Module => {}
+            // Impossible positions because lambdas and comprehensions can't contain statements.
+            ScopeKind::Lambda(_)
+            | ScopeKind::Generator { .. }
+            | ScopeKind::Type
+            | ScopeKind::DunderClassCell => {}
+        }
+
+        for statement in self.semantic.current_statements().skip(1) {
+            if matches!(statement, Stmt::Try(_)) {
+                return Some(LazyImportContext::TryExceptBlocks);
+            }
+        }
+
+        None
+    }
+
     /// Return the preferred quote for a generated `StringLiteral` node, given where we are in the
     /// AST.
     fn preferred_quote(&self) -> Quote {
@@ -803,26 +826,7 @@ impl SemanticSyntaxContext for Checker<'_> {
     }
 
     fn lazy_import_context(&self) -> Option<LazyImportContext> {
-        match self.semantic.current_scope().kind {
-            // Possible, but invalid positions.
-            ScopeKind::Function(_) => return Some(LazyImportContext::Function),
-            ScopeKind::Class(_) => return Some(LazyImportContext::Class),
-            // Valid position.
-            ScopeKind::Module => {}
-            // Impossible positions because lambdas and comprehensions can't contain statements.
-            ScopeKind::Lambda(_)
-            | ScopeKind::Generator { .. }
-            | ScopeKind::Type
-            | ScopeKind::DunderClassCell => {}
-        }
-
-        for statement in self.semantic.current_statements().skip(1) {
-            if matches!(statement, Stmt::Try(_)) {
-                return Some(LazyImportContext::TryExceptBlocks);
-            }
-        }
-
-        None
+        self.lazy_import_context()
     }
 
     fn in_async_context(&self) -> bool {

crates/ruff_linter/src/codes.rs

@@ -435,6 +435,7 @@ pub fn code_to_rule(linter: Linter, code: &str) -> Option<(RuleGroup, Rule)> {
         (Flake8TidyImports, "251") => rules::flake8_tidy_imports::rules::BannedApi,
         (Flake8TidyImports, "252") => rules::flake8_tidy_imports::rules::RelativeImports,
         (Flake8TidyImports, "253") => rules::flake8_tidy_imports::rules::BannedModuleLevelImports,
+        (Flake8TidyImports, "254") => rules::flake8_tidy_imports::rules::BannedEagerImports,
 
         // flake8-return
         (Flake8Return, "501") => rules::flake8_return::rules::UnnecessaryReturnNone,