Add DJ015 for leading slashes as well

crates/ruff_linter/resources/test/fixtures/flake8_django/DJ015.py

@@ -0,0 +1,48 @@
+from django.urls import path
+from . import views
+
+# Errors - leading slash
+urlpatterns = [
+    path("/help/", views.help_view),  # DJ015
+    path("/about/", views.about_view),  # DJ015
+    path("/contact/", views.contact_view),  # DJ015
+    path("/api/users/", views.users_view),  # DJ015
+    path("/blog/posts/", views.posts_view),  # DJ015
+]
+
+# OK - no leading slash
+urlpatterns_ok = [
+    path("help/", views.help_view),
+    path("about/", views.about_view),
+    path("contact/", views.contact_view),
+    path("api/users/", views.users_view),
+    path("blog/posts/", views.posts_view),
+]
+
+# OK - just root path
+urlpatterns_root = [
+    path("/", views.index_view),
+    path("", views.home_view),
+]
+
+# OK - with path parameters
+urlpatterns_params = [
+    path("users/<int:id>/", views.user_detail),
+    path("posts/<slug:slug>/", views.post_detail),
+]
+
+# Mixed cases
+urlpatterns_mixed = [
+    path("good/", views.good_view),
+    path("/bad/", views.bad_view),  # DJ015
+    path("also-good/", views.also_good_view),
+    path("/also-bad/", views.also_bad_view),  # DJ015
+]
+
+# Edge cases with different quote styles
+urlpatterns_quotes = [
+    path('/single-quote/', views.single_quote_view),  # DJ015
+    path("/double-quote/", views.double_quote_view),  # DJ015
+    path('''/triple-single/''', views.triple_single_view),  # DJ015
+    path("""/triple-double/""", views.triple_double_view),  # DJ015
+]

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

@@ -1184,6 +1184,9 @@ pub(crate) fn expression(expr: &Expr, checker: &Checker) {
             if checker.is_rule_enabled(Rule::DjangoURLPathWithoutTrailingSlash) {
                 flake8_django::rules::url_path_without_trailing_slash(checker, call);
             }
+            if checker.is_rule_enabled(Rule::DjangoURLPathWithLeadingSlash) {
+                flake8_django::rules::url_path_with_leading_slash(checker, call);
+            }
             if checker.is_rule_enabled(Rule::UnsupportedMethodCallOnAll) {
                 flake8_pyi::rules::unsupported_method_call_on_all(checker, func);
             }

crates/ruff_linter/src/codes.rs

@@ -1101,6 +1101,7 @@ pub fn code_to_rule(linter: Linter, code: &str) -> Option<(RuleGroup, Rule)> {
         (Flake8Django, "012") => rules::flake8_django::rules::DjangoUnorderedBodyContentInModel,
         (Flake8Django, "013") => rules::flake8_django::rules::DjangoNonLeadingReceiverDecorator,
         (Flake8Django, "014") => rules::flake8_django::rules::DjangoURLPathWithoutTrailingSlash,
+        (Flake8Django, "015") => rules::flake8_django::rules::DjangoURLPathWithLeadingSlash,
 
         // flynt
         // Reserved: (Flynt, "001") => Rule: :StringConcatenationToFString,

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

@@ -19,6 +19,7 @@ mod tests {
     #[test_case(Rule::DjangoAllWithModelForm, Path::new("DJ007.py"))]
     #[test_case(Rule::DjangoModelWithoutDunderStr, Path::new("DJ008.py"))]
     #[test_case(Rule::DjangoURLPathWithoutTrailingSlash, Path::new("DJ014.py"))]
+    #[test_case(Rule::DjangoURLPathWithLeadingSlash, Path::new("DJ015.py"))]
     #[test_case(Rule::DjangoUnorderedBodyContentInModel, Path::new("DJ012.py"))]
     #[test_case(Rule::DjangoNonLeadingReceiverDecorator, Path::new("DJ013.py"))]
     fn rules(rule_code: Rule, path: &Path) -> Result<()> {

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

@@ -5,6 +5,7 @@ pub(crate) use model_without_dunder_str::*;
 pub(crate) use non_leading_receiver_decorator::*;
 pub(crate) use nullable_model_string_field::*;
 pub(crate) use unordered_body_content_in_model::*;
+pub(crate) use url_path_with_leading_slash::*;
 pub(crate) use url_path_without_trailing_slash::*;
 
 mod all_with_model_form;
@@ -14,4 +15,5 @@ mod model_without_dunder_str;
 mod non_leading_receiver_decorator;
 mod nullable_model_string_field;
 mod unordered_body_content_in_model;
+mod url_path_with_leading_slash;
 mod url_path_without_trailing_slash;

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

@@ -0,0 +1,121 @@
+use ruff_macros::{ViolationMetadata, derive_message_formats};
+use ruff_python_ast::{self as ast, Expr};
+use ruff_python_semantic::Modules;
+use ruff_text_size::{Ranged, TextSize};
+
+use crate::checkers::ast::Checker;
+use crate::{AlwaysFixableViolation, Edit, Fix};
+
+/// ## What it does
+/// Checks that all Django URL route definitions using `django.urls.path()`
+/// do not start with a leading slash.
+///
+/// ## Why is this bad?
+/// Django's URL patterns should not start with a leading slash. When using
+/// `include()` or when patterns are combined, leading slashes can cause
+/// issues with URL resolution. The Django documentation recommends that
+/// URL patterns should not have leading slashes, as they are not necessary
+/// and can lead to unexpected behavior.
+///
+/// ## Example
+/// ```python
+/// from django.urls import path
+/// from . import views
+///
+/// urlpatterns = [
+///     path("/help/", views.help_view),  # Leading slash
+///     path("/about/", views.about_view),  # Leading slash
+/// ]
+/// ```
+///
+/// Use instead:
+/// ```python
+/// from django.urls import path
+/// from . import views
+///
+/// urlpatterns = [
+///     path("help/", views.help_view),
+///     path("about/", views.about_view),
+/// ]
+/// ```
+///
+/// ## References
+/// - [Django documentation: URL dispatcher](https://docs.djangoproject.com/en/stable/topics/http/urls/)
+#[derive(ViolationMetadata)]
+#[violation_metadata(preview_since = "v0.14.1")]
+pub(crate) struct DjangoURLPathWithLeadingSlash {
+    url_pattern: String,
+}
+
+impl AlwaysFixableViolation for DjangoURLPathWithLeadingSlash {
+    #[derive_message_formats]
+    fn message(&self) -> String {
+        let DjangoURLPathWithLeadingSlash { url_pattern } = self;
+        format!("URL route `{url_pattern}` has an unnecessary leading slash")
+    }
+
+    fn fix_title(&self) -> String {
+        "Remove leading slash".to_string()
+    }
+}
+
+/// DJ015
+pub(crate) fn url_path_with_leading_slash(checker: &Checker, call: &ast::ExprCall) {
+    if !checker.semantic().seen_module(Modules::DJANGO) {
+        return;
+    }
+
+    // Check if this is a call to django.urls.path
+    if !checker
+        .semantic()
+        .resolve_qualified_name(&call.func)
+        .is_some_and(|qualified_name| {
+            matches!(qualified_name.segments(), ["django", "urls", "path"])
+        })
+    {
+        return;
+    }
+
+    // Get the first argument (the route pattern)
+    let Some(route_arg) = call.arguments.args.first() else {
+        return;
+    };
+
+    // Check if it's a string literal
+    if let Expr::StringLiteral(ast::ExprStringLiteral { value, .. }) = route_arg {
+        let route = value.to_str();
+
+        // Skip empty strings and root path "/"
+        if route.is_empty() || route == "/" {
+            return;
+        }
+
+        // Check if route starts with a leading slash
+        if route.starts_with('/') {
+            // Report diagnostic for routes with leading slash
+            let mut diagnostic = checker.report_diagnostic(
+                DjangoURLPathWithLeadingSlash {
+                    url_pattern: route.to_string(),
+                },
+                route_arg.range(),
+            );
+
+            // Determine the quote style to find the insertion point for removal
+            let string_content = checker.locator().slice(route_arg.range());
+            let quote_len =
+                if string_content.starts_with("'''") || string_content.starts_with("\"\"\"") {
+                    3
+                } else if string_content.starts_with('\'') || string_content.starts_with('"') {
+                    1
+                } else {
+                    return; // Invalid string format
+                };
+
+            // Remove the leading slash (after the opening quote(s))
+            let removal_start = route_arg.range().start() + TextSize::new(quote_len);
+            let removal_end = removal_start + TextSize::new(1); // Remove one character (the slash)
+
+            diagnostic.set_fix(Fix::safe_edit(Edit::deletion(removal_start, removal_end)));
+        }
+    }
+}

crates/ruff_linter/src/rules/flake8_django/snapshots/ruff_linter__rules__flake8_django__tests__DJ015_DJ015.py.snap

@@ -0,0 +1,216 @@
+---
+source: crates/ruff_linter/src/rules/flake8_django/mod.rs
+---
+DJ015 [*] URL route `/help/` has an unnecessary leading slash
+ --> DJ015.py:6:10
+  |
+4 | # Errors - leading slash
+5 | urlpatterns = [
+6 |     path("/help/", views.help_view),  # DJ015
+  |          ^^^^^^^^
+7 |     path("/about/", views.about_view),  # DJ015
+8 |     path("/contact/", views.contact_view),  # DJ015
+  |
+help: Remove leading slash
+3 | 
+4 | # Errors - leading slash
+5 | urlpatterns = [
+  -     path("/help/", views.help_view),  # DJ015
+6 +     path("help/", views.help_view),  # DJ015
+7 |     path("/about/", views.about_view),  # DJ015
+8 |     path("/contact/", views.contact_view),  # DJ015
+9 |     path("/api/users/", views.users_view),  # DJ015
+
+DJ015 [*] URL route `/about/` has an unnecessary leading slash
+ --> DJ015.py:7:10
+  |
+5 | urlpatterns = [
+6 |     path("/help/", views.help_view),  # DJ015
+7 |     path("/about/", views.about_view),  # DJ015
+  |          ^^^^^^^^^
+8 |     path("/contact/", views.contact_view),  # DJ015
+9 |     path("/api/users/", views.users_view),  # DJ015
+  |
+help: Remove leading slash
+4  | # Errors - leading slash
+5  | urlpatterns = [
+6  |     path("/help/", views.help_view),  # DJ015
+   -     path("/about/", views.about_view),  # DJ015
+7  +     path("about/", views.about_view),  # DJ015
+8  |     path("/contact/", views.contact_view),  # DJ015
+9  |     path("/api/users/", views.users_view),  # DJ015
+10 |     path("/blog/posts/", views.posts_view),  # DJ015
+
+DJ015 [*] URL route `/contact/` has an unnecessary leading slash
+  --> DJ015.py:8:10
+   |
+ 6 |     path("/help/", views.help_view),  # DJ015
+ 7 |     path("/about/", views.about_view),  # DJ015
+ 8 |     path("/contact/", views.contact_view),  # DJ015
+   |          ^^^^^^^^^^^
+ 9 |     path("/api/users/", views.users_view),  # DJ015
+10 |     path("/blog/posts/", views.posts_view),  # DJ015
+   |
+help: Remove leading slash
+5  | urlpatterns = [
+6  |     path("/help/", views.help_view),  # DJ015
+7  |     path("/about/", views.about_view),  # DJ015
+   -     path("/contact/", views.contact_view),  # DJ015
+8  +     path("contact/", views.contact_view),  # DJ015
+9  |     path("/api/users/", views.users_view),  # DJ015
+10 |     path("/blog/posts/", views.posts_view),  # DJ015
+11 | ]
+
+DJ015 [*] URL route `/api/users/` has an unnecessary leading slash
+  --> DJ015.py:9:10
+   |
+ 7 |     path("/about/", views.about_view),  # DJ015
+ 8 |     path("/contact/", views.contact_view),  # DJ015
+ 9 |     path("/api/users/", views.users_view),  # DJ015
+   |          ^^^^^^^^^^^^^
+10 |     path("/blog/posts/", views.posts_view),  # DJ015
+11 | ]
+   |
+help: Remove leading slash
+6  |     path("/help/", views.help_view),  # DJ015
+7  |     path("/about/", views.about_view),  # DJ015
+8  |     path("/contact/", views.contact_view),  # DJ015
+   -     path("/api/users/", views.users_view),  # DJ015
+9  +     path("api/users/", views.users_view),  # DJ015
+10 |     path("/blog/posts/", views.posts_view),  # DJ015
+11 | ]
+12 | 
+
+DJ015 [*] URL route `/blog/posts/` has an unnecessary leading slash
+  --> DJ015.py:10:10
+   |
+ 8 |     path("/contact/", views.contact_view),  # DJ015
+ 9 |     path("/api/users/", views.users_view),  # DJ015
+10 |     path("/blog/posts/", views.posts_view),  # DJ015
+   |          ^^^^^^^^^^^^^^
+11 | ]
+   |
+help: Remove leading slash
+7  |     path("/about/", views.about_view),  # DJ015
+8  |     path("/contact/", views.contact_view),  # DJ015
+9  |     path("/api/users/", views.users_view),  # DJ015
+   -     path("/blog/posts/", views.posts_view),  # DJ015
+10 +     path("blog/posts/", views.posts_view),  # DJ015
+11 | ]
+12 | 
+13 | # OK - no leading slash
+
+DJ015 [*] URL route `/bad/` has an unnecessary leading slash
+  --> DJ015.py:37:10
+   |
+35 | urlpatterns_mixed = [
+36 |     path("good/", views.good_view),
+37 |     path("/bad/", views.bad_view),  # DJ015
+   |          ^^^^^^^
+38 |     path("also-good/", views.also_good_view),
+39 |     path("/also-bad/", views.also_bad_view),  # DJ015
+   |
+help: Remove leading slash
+34 | # Mixed cases
+35 | urlpatterns_mixed = [
+36 |     path("good/", views.good_view),
+   -     path("/bad/", views.bad_view),  # DJ015
+37 +     path("bad/", views.bad_view),  # DJ015
+38 |     path("also-good/", views.also_good_view),
+39 |     path("/also-bad/", views.also_bad_view),  # DJ015
+40 | ]
+
+DJ015 [*] URL route `/also-bad/` has an unnecessary leading slash
+  --> DJ015.py:39:10
+   |
+37 |     path("/bad/", views.bad_view),  # DJ015
+38 |     path("also-good/", views.also_good_view),
+39 |     path("/also-bad/", views.also_bad_view),  # DJ015
+   |          ^^^^^^^^^^^^
+40 | ]
+   |
+help: Remove leading slash
+36 |     path("good/", views.good_view),
+37 |     path("/bad/", views.bad_view),  # DJ015
+38 |     path("also-good/", views.also_good_view),
+   -     path("/also-bad/", views.also_bad_view),  # DJ015
+39 +     path("also-bad/", views.also_bad_view),  # DJ015
+40 | ]
+41 | 
+42 | # Edge cases with different quote styles
+
+DJ015 [*] URL route `/single-quote/` has an unnecessary leading slash
+  --> DJ015.py:44:10
+   |
+42 | # Edge cases with different quote styles
+43 | urlpatterns_quotes = [
+44 |     path('/single-quote/', views.single_quote_view),  # DJ015
+   |          ^^^^^^^^^^^^^^^^
+45 |     path("/double-quote/", views.double_quote_view),  # DJ015
+46 |     path('''/triple-single/''', views.triple_single_view),  # DJ015
+   |
+help: Remove leading slash
+41 | 
+42 | # Edge cases with different quote styles
+43 | urlpatterns_quotes = [
+   -     path('/single-quote/', views.single_quote_view),  # DJ015
+44 +     path('single-quote/', views.single_quote_view),  # DJ015
+45 |     path("/double-quote/", views.double_quote_view),  # DJ015
+46 |     path('''/triple-single/''', views.triple_single_view),  # DJ015
+47 |     path("""/triple-double/""", views.triple_double_view),  # DJ015
+
+DJ015 [*] URL route `/double-quote/` has an unnecessary leading slash
+  --> DJ015.py:45:10
+   |
+43 | urlpatterns_quotes = [
+44 |     path('/single-quote/', views.single_quote_view),  # DJ015
+45 |     path("/double-quote/", views.double_quote_view),  # DJ015
+   |          ^^^^^^^^^^^^^^^^
+46 |     path('''/triple-single/''', views.triple_single_view),  # DJ015
+47 |     path("""/triple-double/""", views.triple_double_view),  # DJ015
+   |
+help: Remove leading slash
+42 | # Edge cases with different quote styles
+43 | urlpatterns_quotes = [
+44 |     path('/single-quote/', views.single_quote_view),  # DJ015
+   -     path("/double-quote/", views.double_quote_view),  # DJ015
+45 +     path("double-quote/", views.double_quote_view),  # DJ015
+46 |     path('''/triple-single/''', views.triple_single_view),  # DJ015
+47 |     path("""/triple-double/""", views.triple_double_view),  # DJ015
+48 | ]
+
+DJ015 [*] URL route `/triple-single/` has an unnecessary leading slash
+  --> DJ015.py:46:10
+   |
+44 |     path('/single-quote/', views.single_quote_view),  # DJ015
+45 |     path("/double-quote/", views.double_quote_view),  # DJ015
+46 |     path('''/triple-single/''', views.triple_single_view),  # DJ015
+   |          ^^^^^^^^^^^^^^^^^^^^^
+47 |     path("""/triple-double/""", views.triple_double_view),  # DJ015
+48 | ]
+   |
+help: Remove leading slash
+43 | urlpatterns_quotes = [
+44 |     path('/single-quote/', views.single_quote_view),  # DJ015
+45 |     path("/double-quote/", views.double_quote_view),  # DJ015
+   -     path('''/triple-single/''', views.triple_single_view),  # DJ015
+46 +     path('''triple-single/''', views.triple_single_view),  # DJ015
+47 |     path("""/triple-double/""", views.triple_double_view),  # DJ015
+48 | ]
+
+DJ015 [*] URL route `/triple-double/` has an unnecessary leading slash
+  --> DJ015.py:47:10
+   |
+45 |     path("/double-quote/", views.double_quote_view),  # DJ015
+46 |     path('''/triple-single/''', views.triple_single_view),  # DJ015
+47 |     path("""/triple-double/""", views.triple_double_view),  # DJ015
+   |          ^^^^^^^^^^^^^^^^^^^^^
+48 | ]
+   |
+help: Remove leading slash
+44 |     path('/single-quote/', views.single_quote_view),  # DJ015
+45 |     path("/double-quote/", views.double_quote_view),  # DJ015
+46 |     path('''/triple-single/''', views.triple_single_view),  # DJ015
+   -     path("""/triple-double/""", views.triple_double_view),  # DJ015
+47 +     path("""triple-double/""", views.triple_double_view),  # DJ015
+48 | ]

ruff.schema.json

@@ -3158,6 +3158,7 @@
         "DJ012",
         "DJ013",
         "DJ014",
+        "DJ015",
         "DOC",
         "DOC1",
         "DOC10",