From b8d0b4337672d9ba4c73aa40201bd5707b539359 Mon Sep 17 00:00:00 2001
From: Nigel Small <nasmall@pm.me>
Date: Tue, 1 Jun 2021 10:26:54 +0100
Subject: [PATCH] Fixes #903 by reintroducing entity-level label/key overrides

---
 py2neo/data/__init__.py        | 23 ++++++++--
 test/integration/test_merge.py | 78 ++++++++++++++++++++++++++++++++++
 2 files changed, 97 insertions(+), 4 deletions(-)

diff --git a/py2neo/data/__init__.py b/py2neo/data/__init__.py
index a5131f72..ae82c987 100644
--- a/py2neo/data/__init__.py
+++ b/py2neo/data/__init__.py
@@ -279,12 +279,21 @@ def __db_merge__(self, tx, primary_label=None, primary_key=None):
         node_dict = {}
         for node in self.nodes:
             if not self._is_bound(node, graph):
-                if node.__model__ is None:
-                    p_label = primary_label
-                    p_key = primary_key
-                else:
+                # Determine primary label
+                if node.__primarylabel__ is not None:
+                    p_label = node.__primarylabel__
+                elif node.__model__ is not None:
                     p_label = node.__model__.__primarylabel__ or primary_label
+                else:
+                    p_label = primary_label
+                # Determine primary key
+                if node.__primarykey__ is not None:
+                    p_key = node.__primarykey__
+                elif node.__model__ is not None:
                     p_key = node.__model__.__primarykey__ or primary_key
+                else:
+                    p_key = primary_key
+                # Add node to the node dictionary
                 key = (p_label, p_key, frozenset(node.labels))
                 node_dict.setdefault(key, []).append(node)
 
@@ -611,6 +620,12 @@ class Node(Entity):
     #: OGM model class
     __model__ = None
 
+    #: Entity-level override for merge label
+    __primarylabel__ = None
+
+    #: Entity-level override for merge key
+    __primarykey__ = None
+
     @classmethod
     def ref(cls, graph, identity):
         obj = cls()
diff --git a/test/integration/test_merge.py b/test/integration/test_merge.py
index 8e979927..3fa31594 100644
--- a/test/integration/test_merge.py
+++ b/test/integration/test_merge.py
@@ -347,3 +347,81 @@ class ModelB(Model):
     graph.merge(node, label_a, "a")
     assert node.identity != a_id
     assert node.identity == b_id
+
+
+def test_can_merge_node_with_merge_arguments(graph):
+    graph.delete_all()
+    a = Node("Person", name="Alice")
+    graph.merge(a, "Person", "name")
+    assert graph.nodes.match("Person", name="Alice").first() == a
+
+
+def test_can_merge_node_with_primary_label_and_key(graph):
+    graph.delete_all()
+    a = Node("Person", name="Alice")
+    a.__primarylabel__ = "Person"
+    a.__primarykey__ = "name"
+    graph.merge(a)
+    assert graph.nodes.match("Person", name="Alice").first() == a
+
+
+def test_can_merge_node_with_model(graph):
+    from py2neo.ogm import Model
+
+    class Person(Model):
+        __primarylabel__ = "Person"
+        __primarykey__ = "name"
+
+    graph.delete_all()
+
+    a = Node("Person", name="Alice")
+    a.__model__ = Person
+    graph.merge(a)
+    assert graph.nodes.match("Person", name="Alice").first() == a
+
+
+def test_can_merge_node_with_model_overriding_arguments(graph):
+    from py2neo.ogm import Model
+
+    class Person(Model):
+        __primarylabel__ = "Person"
+        __primarykey__ = "name"
+
+    graph.delete_all()
+
+    a = Node("Person", name="Alice")
+    a.__model__ = Person
+    graph.merge(a, "Human", "nom")
+    assert graph.nodes.match("Person", name="Alice").first() == a
+
+
+def test_can_merge_node_with_primary_label_overriding_model(graph):
+    from py2neo.ogm import Model
+
+    class Person(Model):
+        __primarylabel__ = "Human"
+        __primarykey__ = "name"
+
+    graph.delete_all()
+
+    a = Node("Person", name="Alice")
+    a.__model__ = Person
+    a.__primarylabel__ = "Person"
+    graph.merge(a)
+    assert graph.nodes.match("Person", name="Alice").first() == a
+
+
+def test_can_merge_node_with_primary_key_overriding_model(graph):
+    from py2neo.ogm import Model
+
+    class Person(Model):
+        __primarylabel__ = "Person"
+        __primarykey__ = "nom"
+
+    graph.delete_all()
+
+    a = Node("Person", name="Alice")
+    a.__model__ = Person
+    a.__primarykey__ = "name"
+    graph.merge(a)
+    assert graph.nodes.match("Person", name="Alice").first() == a