Collect django pk data at the binding layer

Summary: Collect primary key data from the binding layer. In the next diff, we will propagate it to the class metadata layer.

Reviewed By: rchen152

Differential Revision: D85470913

fbshipit-source-id: fdce9485a1ed425674659a946de56353d4b8731a

Author: migeed-z

pyrefly/lib/binding/class.rs

@@ -241,6 +241,9 @@ impl<'a> BindingsBuilder<'a> {
             } = &definition
             {
                 self.extract_pydantic_config_dict(e, &name, &mut pydantic_config_dict);
+
+                // TODO: We will use this to populate the django metadata
+                let _is_django_primary_key = self.extract_django_primary_key(e);
             }
             let (is_initialized_on_class, is_annotated) = match &definition {
                 ClassFieldDefinition::DefinedInMethod { annotation, .. } => {

pyrefly/lib/binding/django.rs

@@ -0,0 +1,32 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+use ruff_python_ast::Expr;
+use ruff_python_ast::name::Name;
+
+use crate::binding::bindings::BindingsBuilder;
+
+const PRIMARY_KEY: Name = Name::new_static("primary_key");
+
+impl<'a> BindingsBuilder<'a> {
+    /// Detect if a field has `primary_key=True` set. This will be used to support Django models with custom primary keys.
+    pub fn extract_django_primary_key(&self, e: &Expr) -> bool {
+        let Some(call) = e.as_call_expr() else {
+            return false;
+        };
+        for keyword in &call.arguments.keywords {
+            if let Some(arg_name) = &keyword.arg
+                && arg_name.as_str() == PRIMARY_KEY.as_str()
+                && let Expr::BooleanLiteral(bl) = &keyword.value
+            {
+                return bl.value;
+            }
+        }
+
+        false
+    }
+}

pyrefly/lib/binding/mod.rs

@@ -9,6 +9,7 @@ pub mod base_class;
 pub mod binding;
 pub mod bindings;
 pub mod class;
+pub mod django;
 pub mod expr;
 pub mod function;
 pub mod narrow;