Make primary field target adapter return early.

.github/workflows/tests.yml

@@ -3,7 +3,7 @@ on: [push, pull_request]
 jobs:
   build:
     if: github.event_name != 'pull_request' || github.event.pull_request.head.repo.full_name != github.event.pull_request.base.repo.full_name
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-22.04
     strategy:
       fail-fast: false
       matrix:

news/1851.bugfix

@@ -0,0 +1 @@
+Optimized performance of DexterityObjectPrimaryFieldTarget adapter. @maurits

src/plone/restapi/serializer/dxcontent.py

@@ -220,23 +220,26 @@ def __init__(self, context, request):
 
     def __call__(self):
         primary_field_name = self.get_primary_field_name()
+        if not primary_field_name:
+            return
         for schema in iterSchemata(self.context):
             read_permissions = mergedTaggedValueDict(schema, READ_PERMISSIONS_KEY)
 
-            for name, field in getFields(schema).items():
-                if not self.check_permission(read_permissions.get(name), self.context):
-                    continue
-
-                if name != primary_field_name:
-                    continue
-
-                target_adapter = queryMultiAdapter(
-                    (field, self.context, self.request), IPrimaryFieldTarget
-                )
-                if target_adapter:
-                    target = target_adapter()
-                    if target:
-                        return target
+            field = getFields(schema).get(primary_field_name)
+            if field is None:
+                continue
+            if not self.check_permission(
+                read_permissions.get(primary_field_name),
+                self.context,
+            ):
+                return
+
+            target_adapter = queryMultiAdapter(
+                (field, self.context, self.request), IPrimaryFieldTarget
+            )
+            if not target_adapter:
+                return
+            return target_adapter()
 
     def get_primary_field_name(self):
         fieldname = None