Add base-class inheritance detection to flake8-django rules

crates/ruff_linter/resources/test/fixtures/flake8_django/DJ012.py

@@ -127,3 +127,21 @@ def get_absolute_url(self):
         pass
 
     middle_name = models.CharField(max_length=32)
+
+
+class BaseModel(models.Model):
+    pass
+
+
+class StrBeforeFieldInheritedModel(BaseModel):
+    """Model with `__str__` before fields."""
+
+    class Meta:
+        verbose_name = "test"
+        verbose_name_plural = "tests"
+
+    def __str__(self):
+        return "foobar"
+
+    first_name = models.CharField(max_length=32)
+

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

@@ -397,27 +397,13 @@ pub(crate) fn statement(stmt: &Stmt, checker: &mut Checker) {
                 flake8_django::rules::nullable_model_string_field(checker, body);
             }
             if checker.enabled(Rule::DjangoExcludeWithModelForm) {
-                if let Some(diagnostic) = flake8_django::rules::exclude_with_model_form(
-                    checker,
-                    arguments.as_deref(),
-                    body,
-                ) {
-                    checker.diagnostics.push(diagnostic);
-                }
+                flake8_django::rules::exclude_with_model_form(checker, class_def);
             }
             if checker.enabled(Rule::DjangoAllWithModelForm) {
-                if let Some(diagnostic) =
-                    flake8_django::rules::all_with_model_form(checker, arguments.as_deref(), body)
-                {
-                    checker.diagnostics.push(diagnostic);
-                }
+                flake8_django::rules::all_with_model_form(checker, class_def)
             }
             if checker.enabled(Rule::DjangoUnorderedBodyContentInModel) {
-                flake8_django::rules::unordered_body_content_in_model(
-                    checker,
-                    arguments.as_deref(),
-                    body,
-                );
+                flake8_django::rules::unordered_body_content_in_model(checker, class_def);
             }
             if !checker.source_type.is_stub() {
                 if checker.enabled(Rule::DjangoModelWithoutDunderStr) {

crates/ruff_linter/src/rules/flake8_django/rules/all_with_model_form.rs

@@ -1,7 +1,6 @@
-use ruff_python_ast::{self as ast, Arguments, Expr, Stmt};
-
 use ruff_diagnostics::{Diagnostic, Violation};
 use ruff_macros::{derive_message_formats, violation};
+use ruff_python_ast::{self as ast, Expr, Stmt};
 use ruff_text_size::Ranged;
 
 use crate::checkers::ast::Checker;
@@ -48,21 +47,12 @@ impl Violation for DjangoAllWithModelForm {
 }
 
 /// DJ007
-pub(crate) fn all_with_model_form(
-    checker: &Checker,
-    arguments: Option<&Arguments>,
-    body: &[Stmt],
-) -> Option<Diagnostic> {
-    if !arguments.is_some_and(|arguments| {
-        arguments
-            .args
-            .iter()
-            .any(|base| is_model_form(base, checker.semantic()))
-    }) {
-        return None;
+pub(crate) fn all_with_model_form(checker: &mut Checker, class_def: &ast::StmtClassDef) {
+    if !is_model_form(class_def, checker.semantic()) {
+        return;
     }
 
-    for element in body {
+    for element in &class_def.body {
         let Stmt::ClassDef(ast::StmtClassDef { name, body, .. }) = element else {
             continue;
         };
@@ -83,18 +73,23 @@ pub(crate) fn all_with_model_form(
                 match value.as_ref() {
                     Expr::StringLiteral(ast::ExprStringLiteral { value, .. }) => {
                         if value == "__all__" {
-                            return Some(Diagnostic::new(DjangoAllWithModelForm, element.range()));
+                            checker
+                                .diagnostics
+                                .push(Diagnostic::new(DjangoAllWithModelForm, element.range()));
+                            return;
                         }
                     }
                     Expr::BytesLiteral(ast::ExprBytesLiteral { value, .. }) => {
                         if value == "__all__".as_bytes() {
-                            return Some(Diagnostic::new(DjangoAllWithModelForm, element.range()));
+                            checker
+                                .diagnostics
+                                .push(Diagnostic::new(DjangoAllWithModelForm, element.range()));
+                            return;
                         }
                     }
                     _ => (),
                 };
             }
         }
     }
-    None
 }

crates/ruff_linter/src/rules/flake8_django/rules/exclude_with_model_form.rs

@@ -1,7 +1,6 @@
-use ruff_python_ast::{self as ast, Arguments, Expr, Stmt};
-
 use ruff_diagnostics::{Diagnostic, Violation};
 use ruff_macros::{derive_message_formats, violation};
+use ruff_python_ast::{self as ast, Expr, Stmt};
 use ruff_text_size::Ranged;
 
 use crate::checkers::ast::Checker;
@@ -46,21 +45,12 @@ impl Violation for DjangoExcludeWithModelForm {
 }
 
 /// DJ006
-pub(crate) fn exclude_with_model_form(
-    checker: &Checker,
-    arguments: Option<&Arguments>,
-    body: &[Stmt],
-) -> Option<Diagnostic> {
-    if !arguments.is_some_and(|arguments| {
-        arguments
-            .args
-            .iter()
-            .any(|base| is_model_form(base, checker.semantic()))
-    }) {
-        return None;
+pub(crate) fn exclude_with_model_form(checker: &mut Checker, class_def: &ast::StmtClassDef) {
+    if !is_model_form(class_def, checker.semantic()) {
+        return;
     }
 
-    for element in body {
+    for element in &class_def.body {
         let Stmt::ClassDef(ast::StmtClassDef { name, body, .. }) = element else {
             continue;
         };
@@ -76,10 +66,12 @@ pub(crate) fn exclude_with_model_form(
                     continue;
                 };
                 if id == "exclude" {
-                    return Some(Diagnostic::new(DjangoExcludeWithModelForm, target.range()));
+                    checker
+                        .diagnostics
+                        .push(Diagnostic::new(DjangoExcludeWithModelForm, target.range()));
+                    return;
                 }
             }
         }
     }
-    None
 }

crates/ruff_linter/src/rules/flake8_django/rules/helpers.rs

@@ -1,17 +1,17 @@
-use ruff_python_ast::Expr;
+use ruff_python_ast::{self as ast, Expr};
 
-use ruff_python_semantic::SemanticModel;
+use ruff_python_semantic::{analyze, SemanticModel};
 
 /// Return `true` if a Python class appears to be a Django model, based on its base classes.
-pub(super) fn is_model(base: &Expr, semantic: &SemanticModel) -> bool {
-    semantic.resolve_call_path(base).is_some_and(|call_path| {
+pub(super) fn is_model(class_def: &ast::StmtClassDef, semantic: &SemanticModel) -> bool {
+    analyze::class::any_over_body(class_def, semantic, &|call_path| {
         matches!(call_path.as_slice(), ["django", "db", "models", "Model"])
     })
 }
 
 /// Return `true` if a Python class appears to be a Django model form, based on its base classes.
-pub(super) fn is_model_form(base: &Expr, semantic: &SemanticModel) -> bool {
-    semantic.resolve_call_path(base).is_some_and(|call_path| {
+pub(super) fn is_model_form(class_def: &ast::StmtClassDef, semantic: &SemanticModel) -> bool {
+    analyze::class::any_over_body(class_def, semantic, &|call_path| {
         matches!(
             call_path.as_slice(),
             ["django", "forms", "ModelForm"] | ["django", "forms", "models", "ModelForm"]

crates/ruff_linter/src/rules/flake8_django/rules/model_without_dunder_str.rs

@@ -1,10 +1,9 @@
-use ruff_python_ast::{self as ast, Arguments, Expr, Stmt};
-
 use ruff_diagnostics::{Diagnostic, Violation};
 use ruff_macros::{derive_message_formats, violation};
 use ruff_python_ast::helpers::is_const_true;
+use ruff_python_ast::identifier::Identifier;
+use ruff_python_ast::{self as ast, Expr, Stmt};
 use ruff_python_semantic::SemanticModel;
-use ruff_text_size::Ranged;
 
 use crate::checkers::ast::Checker;
 
@@ -52,57 +51,39 @@ impl Violation for DjangoModelWithoutDunderStr {
 }
 
 /// DJ008
-pub(crate) fn model_without_dunder_str(
-    checker: &mut Checker,
-    ast::StmtClassDef {
-        name,
-        arguments,
-        body,
-        ..
-    }: &ast::StmtClassDef,
-) {
-    if !is_non_abstract_model(arguments.as_deref(), body, checker.semantic()) {
+pub(crate) fn model_without_dunder_str(checker: &mut Checker, class_def: &ast::StmtClassDef) {
+    if !is_non_abstract_model(class_def, checker.semantic()) {
         return;
     }
-    if has_dunder_method(body) {
+    if has_dunder_method(class_def) {
         return;
     }
-    checker
-        .diagnostics
-        .push(Diagnostic::new(DjangoModelWithoutDunderStr, name.range()));
+    checker.diagnostics.push(Diagnostic::new(
+        DjangoModelWithoutDunderStr,
+        class_def.identifier(),
+    ));
 }
 
-fn has_dunder_method(body: &[Stmt]) -> bool {
-    body.iter().any(|val| match val {
-        Stmt::FunctionDef(ast::StmtFunctionDef { name, .. }) => {
-            if name == "__str__" {
-                return true;
-            }
-            false
-        }
+/// Returns `true` if the class has `__str__` method.
+fn has_dunder_method(class_def: &ast::StmtClassDef) -> bool {
+    class_def.body.iter().any(|val| match val {
+        Stmt::FunctionDef(ast::StmtFunctionDef { name, .. }) => name == "__str__",
         _ => false,
     })
 }
 
-fn is_non_abstract_model(
-    arguments: Option<&Arguments>,
-    body: &[Stmt],
-    semantic: &SemanticModel,
-) -> bool {
-    let Some(Arguments { args: bases, .. }) = arguments else {
-        return false;
-    };
-
-    if is_model_abstract(body) {
-        return false;
+/// Returns `true` if the class is a non-abstract Django model.
+fn is_non_abstract_model(class_def: &ast::StmtClassDef, semantic: &SemanticModel) -> bool {
+    if class_def.bases().is_empty() || is_model_abstract(class_def) {
+        false
+    } else {
+        helpers::is_model(class_def, semantic)
     }
-
-    bases.iter().any(|base| helpers::is_model(base, semantic))
 }
 
 /// Check if class is abstract, in terms of Django model inheritance.
-fn is_model_abstract(body: &[Stmt]) -> bool {
-    for element in body {
+fn is_model_abstract(class_def: &ast::StmtClassDef) -> bool {
+    for element in &class_def.body {
         let Stmt::ClassDef(ast::StmtClassDef { name, body, .. }) = element else {
             continue;
         };

crates/ruff_linter/src/rules/flake8_django/rules/unordered_body_content_in_model.rs

@@ -1,9 +1,8 @@
 use std::fmt;
 
-use ruff_python_ast::{self as ast, Arguments, Expr, Stmt};
-
 use ruff_diagnostics::{Diagnostic, Violation};
 use ruff_macros::{derive_message_formats, violation};
+use ruff_python_ast::{self as ast, Expr, Stmt};
 use ruff_python_semantic::SemanticModel;
 use ruff_text_size::Ranged;
 
@@ -79,6 +78,50 @@ impl Violation for DjangoUnorderedBodyContentInModel {
     }
 }
 
+/// DJ012
+pub(crate) fn unordered_body_content_in_model(
+    checker: &mut Checker,
+    class_def: &ast::StmtClassDef,
+) {
+    if !helpers::is_model(class_def, checker.semantic()) {
+        return;
+    }
+
+    // Track all the element types we've seen so far.
+    let mut element_types = Vec::new();
+    let mut prev_element_type = None;
+    for element in &class_def.body {
+        let Some(element_type) = get_element_type(element, checker.semantic()) else {
+            continue;
+        };
+
+        // Skip consecutive elements of the same type. It's less noisy to only report
+        // violations at type boundaries (e.g., avoid raising a violation for _every_
+        // field declaration that's out of order).
+        if prev_element_type == Some(element_type) {
+            continue;
+        }
+
+        prev_element_type = Some(element_type);
+
+        if let Some(&prev_element_type) = element_types
+            .iter()
+            .find(|&&prev_element_type| prev_element_type > element_type)
+        {
+            let diagnostic = Diagnostic::new(
+                DjangoUnorderedBodyContentInModel {
+                    element_type,
+                    prev_element_type,
+                },
+                element.range(),
+            );
+            checker.diagnostics.push(diagnostic);
+        } else {
+            element_types.push(element_type);
+        }
+    }
+}
+
 #[derive(Debug, Clone, Copy, PartialOrd, Ord, PartialEq, Eq)]
 enum ContentType {
     FieldDeclaration,
@@ -140,53 +183,3 @@ fn get_element_type(element: &Stmt, semantic: &SemanticModel) -> Option<ContentT
         _ => None,
     }
 }
-
-/// DJ012
-pub(crate) fn unordered_body_content_in_model(
-    checker: &mut Checker,
-    arguments: Option<&Arguments>,
-    body: &[Stmt],
-) {
-    if !arguments.is_some_and(|arguments| {
-        arguments
-            .args
-            .iter()
-            .any(|base| helpers::is_model(base, checker.semantic()))
-    }) {
-        return;
-    }
-
-    // Track all the element types we've seen so far.
-    let mut element_types = Vec::new();
-    let mut prev_element_type = None;
-    for element in body {
-        let Some(element_type) = get_element_type(element, checker.semantic()) else {
-            continue;
-        };
-
-        // Skip consecutive elements of the same type. It's less noisy to only report
-        // violations at type boundaries (e.g., avoid raising a violation for _every_
-        // field declaration that's out of order).
-        if prev_element_type == Some(element_type) {
-            continue;
-        }
-
-        prev_element_type = Some(element_type);
-
-        if let Some(&prev_element_type) = element_types
-            .iter()
-            .find(|&&prev_element_type| prev_element_type > element_type)
-        {
-            let diagnostic = Diagnostic::new(
-                DjangoUnorderedBodyContentInModel {
-                    element_type,
-                    prev_element_type,
-                },
-                element.range(),
-            );
-            checker.diagnostics.push(diagnostic);
-        } else {
-            element_types.push(element_type);
-        }
-    }
-}