Fix dict merge issue and add tests

ansible_collections/arista/avd/molecule/eos_designs_unit_tests/intended/configs/core-1-isis-sr-ldp.cfg

@@ -186,6 +186,8 @@ interface Ethernet10
    description P2P_LINK_TO_CORE-2-OSPF-LDP_Ethernet10
    no shutdown
    mtu 1500
+   l2 mtu 2222
+   l2 mru 2222
    speed forced 1000full
    no switchport
    ip address 100.64.48.12/31

ansible_collections/arista/avd/molecule/eos_designs_unit_tests/intended/configs/core-2-ospf-ldp.cfg

@@ -144,6 +144,8 @@ interface Ethernet10
    description P2P_LINK_TO_CORE-1-ISIS-SR-LDP_Ethernet10
    no shutdown
    mtu 1500
+   l2 mtu 2222
+   l2 mru 2222
    speed forced 1000full
    no switchport
    ip address 100.64.48.13/31

ansible_collections/arista/avd/molecule/eos_designs_unit_tests/intended/structured_configs/core-1-isis-sr-ldp.yml

@@ -248,6 +248,8 @@ ethernet_interfaces:
       igp_sync: true
   description: P2P_LINK_TO_CORE-2-OSPF-LDP_Ethernet10
   speed: forced 1000full
+  l2_mru: 2222
+  l2_mtu: 2222
 - name: Ethernet12
   peer: core-2-ospf-ldp
   peer_interface: Ethernet12

ansible_collections/arista/avd/molecule/eos_designs_unit_tests/intended/structured_configs/core-2-ospf-ldp.yml

@@ -190,6 +190,8 @@ ethernet_interfaces:
       igp_sync: true
   description: P2P_LINK_TO_CORE-1-ISIS-SR-LDP_Ethernet10
   speed: forced 1000full
+  l2_mru: 2222
+  l2_mtu: 2222
 - name: Ethernet12
   peer: core-1-isis-sr-ldp
   peer_interface: Ethernet12

ansible_collections/arista/avd/molecule/eos_designs_unit_tests/inventory/group_vars/CORE_UNIT_TESTS.yml

@@ -77,6 +77,9 @@ core_interfaces:
       speed: "forced 1000full"
       mtu: 1500
       ip_pool: underlay_pool
+      # Testing merge of structured config on profile and link.
+      structured_config:
+        l2_mtu: 2222
 
   p2p_links:
 
@@ -139,6 +142,9 @@ core_interfaces:
       id: 7
       interfaces: [ Ethernet10, Ethernet10 ]
       profile: ospf_bb_profile
+      # Testing merge of structured config on profile and link.
+      structured_config:
+        l2_mru: 2222
 
     # core Port-Channel
     - nodes: [ core-1-isis-sr-ldp, core-2-ospf-ldp ]

ansible_collections/arista/avd/molecule/eos_designs_unit_tests/inventory/group_vars/UPLINK_MLAG_STRUCTURED_CONFIG_L2LEAFS.yml

@@ -11,20 +11,22 @@ l2leaf:
           level: 25
         unknown_unicast:
           level: 25
-      switchport:
-        trunk:
-          native_vlan_tag: true
     mlag_interfaces: [ Ethernet3, Ethernet4 ]
     mlag_peer_ipv4_pool: 10.255.252.0/24
-    mlag_port_channel_structured_config:  # Setting structured config here but it is overridden on group level and applied again on node level.
-      description: "Port-channel description not being used because it is overridden on node-group level."
+    mlag_port_channel_structured_config:  # Setting structured config here but it is overridden by 'null' on group level and applied again on node level.
+      description: "Port-channel description not being used because it is overridden by 'null' on node-group level."
 
     spanning_tree_mode: mstp
     spanning_tree_priority: 16384
   node_groups:
     - group: UPLINK-MLAG-STRUCTURED-CONFIG-L2LEAF1
       # Testing the inheritance works correctly when nullifying a dict in the group and then applying a new one per node.
       mlag_port_channel_structured_config: null
+      # Testing merging of uplink_structured_config which is a dict type with no schema.
+      uplink_structured_config:
+        switchport:
+          trunk:
+            native_vlan_tag: true
       nodes:
         - name: UPLINK-MLAG-STRUCTURED-CONFIG-L2LEAF1A
           id: 1

python-avd/pyavd/_schema/models/avd_model.py

@@ -8,7 +8,7 @@
 from typing import TYPE_CHECKING, Any, ClassVar, Literal
 
 from pyavd._schema.coerce_type import coerce_type
-from pyavd._utils import Undefined, UndefinedType
+from pyavd._utils import Undefined, UndefinedType, merge
 
 from .avd_base import AvdBase
 from .avd_indexed_list import AvdIndexedList
@@ -256,8 +256,15 @@ def _deepmerge(self, other: Self, list_merge: Literal["append", "replace"] = "ap
             if issubclass(field_type, AvdBase) and isinstance(old_value, field_type):
                 # Merge in to the existing object
                 old_value._deepmerge(new_value, list_merge=list_merge)
-            else:
-                setattr(self, field, new_value)
+                continue
+
+            if field_type is dict:
+                # In-place deepmerge in to the existing dict without schema.
+                # Deepcopying since merge() does not copy.
+                merge(old_value, deepcopy(new_value), list_merge=list_merge)
+                continue
+
+            setattr(self, field, new_value)
 
     def _inherit(self, other: Self) -> None:
         """Update unset fields on this instance with fields from other instance. No merging."""
@@ -291,12 +298,19 @@ def _deepinherit(self, other: Self) -> None:
             # Inherit the field only if the old value is Undefined.
             if old_value is Undefined:
                 setattr(self, field, deepcopy(new_value))
+                continue
 
             # Merge new value if it is a class with inheritance support.
             field_type = field_info["type"]
             if issubclass(field_type, (AvdModel, AvdIndexedList)) and isinstance(old_value, field_type):
                 # Inherit into the existing object.
                 old_value._deepinherit(new_value)
+                continue
+
+            if field_type is dict:
+                # In-place deepmerge in to the existing dict without schema.
+                # Deepcopying since merge() does not copy.
+                merge(old_value, deepcopy(new_value), list_merge="replace")
 
     def _deepinherited(self, other: Self) -> Self:
         """Return new instance with the result of recursively inheriting unset fields from other instance. Lists are not merged."""

python-avd/pyavd/_utils/merge/__init__.py

@@ -46,7 +46,7 @@ def _strategy_must_match(_config: object, path: list, base: Any, nxt: Any) -> An
 
 def merge(
     base: Any,
-    *nxt_list: list[Any],
+    *nxt_list: Any,
     recursive: bool = True,
     list_merge: str = "append",
     same_key_strategy: str = "override",