Avoid underflow in get_model matching (#8965)

Closes #8962.
astral-sh · Dec 2, 2023 · 22d8a98 · 22d8a98
1 parent 35082b2
commit 22d8a98
Show file tree

Hide file tree

Showing 3 changed files with 24 additions and 1 deletion.
diff --git a/crates/ruff_linter/resources/test/fixtures/pep8_naming/N806.py b/crates/ruff_linter/resources/test/fixtures/pep8_naming/N806.py
@@ -52,3 +52,6 @@ def model_assign() -> None:
 
     Bad = import_string("django.core.exceptions.ValidationError")  # N806
     ValidationError = import_string("django.core.exceptions.ValidationError")  # OK
+
+    Bad = apps.get_model()  # N806
+    Bad = apps.get_model(model_name="Stream")  # N806
diff --git a/crates/ruff_linter/src/rules/pep8_naming/helpers.rs b/crates/ruff_linter/src/rules/pep8_naming/helpers.rs
@@ -101,11 +101,15 @@ pub(super) fn is_django_model_import(name: &str, stmt: &Stmt, semantic: &Semanti
             return false;
         };
 
+        if arguments.is_empty() {
+            return false;
+        }
+
         // Match against, e.g., `apps.get_model("zerver", "Attachment")`.
         if let Some(call_path) = collect_call_path(func.as_ref()) {
             if matches!(call_path.as_slice(), [.., "get_model"]) {
                 if let Some(argument) =
-                    arguments.find_argument("model_name", arguments.args.len() - 1)
+                    arguments.find_argument("model_name", arguments.args.len().saturating_sub(1))
                 {
                     if let Some(string_literal) = argument.as_string_literal_expr() {
                         return string_literal.value.to_str() == name;

diff --git a/...src/rules/pep8_naming/snapshots/ruff_linter__rules__pep8_naming__tests__N806_N806.py.snap b/...src/rules/pep8_naming/snapshots/ruff_linter__rules__pep8_naming__tests__N806_N806.py.snap
@@ -38,4 +38,20 @@ N806.py:53:5: N806 Variable `Bad` in function should be lowercase
 54 |     ValidationError = import_string("django.core.exceptions.ValidationError")  # OK
    |
 
+N806.py:56:5: N806 Variable `Bad` in function should be lowercase
+   |
+54 |     ValidationError = import_string("django.core.exceptions.ValidationError")  # OK
+55 | 
+56 |     Bad = apps.get_model()  # N806
+   |     ^^^ N806
+57 |     Bad = apps.get_model(model_name="Stream")  # N806
+   |
+
+N806.py:57:5: N806 Variable `Bad` in function should be lowercase
+   |
+56 |     Bad = apps.get_model()  # N806
+57 |     Bad = apps.get_model(model_name="Stream")  # N806
+   |     ^^^ N806
+   |
+