EC2: create_route() should allow overlapping CIDR's (#6106)

getmoto · Mar 22, 2023 · 53603b0 · 53603b0
1 parent 681db43
commit 53603b0
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Showing 2 changed files with 14 additions and 12 deletions.
diff --git a/moto/ec2/models/route_tables.py b/moto/ec2/models/route_tables.py
@@ -514,7 +514,7 @@ def __validate_destination_cidr_block(
         for route in route_table.routes.values():
             if not route.destination_cidr_block:
                 continue
-            if not route.local and ip_v4_network.overlaps(
-                ipaddress.IPv4Network(str(route.destination_cidr_block))
+            if not route.local and ip_v4_network == ipaddress.IPv4Network(
+                str(route.destination_cidr_block)
             ):
                 raise RouteAlreadyExistsError(destination_cidr_block)
diff --git a/tests/test_ec2/test_route_tables.py b/tests/test_ec2/test_route_tables.py
@@ -664,16 +664,18 @@ def test_routes_already_exist():
     ex.value.response["ResponseMetadata"].should.have.key("RequestId")
     ex.value.response["Error"]["Code"].should.equal("RouteAlreadyExists")
 
-    with pytest.raises(ClientError) as ex:
-        client.create_route(
-            RouteTableId=main_route_table.id,
-            DestinationCidrBlock=ROUTE_SUB_CIDR,
-            GatewayId=igw.id,
-        )
-
-    ex.value.response["ResponseMetadata"]["HTTPStatusCode"].should.equal(400)
-    ex.value.response["ResponseMetadata"].should.have.key("RequestId")
-    ex.value.response["Error"]["Code"].should.equal("RouteAlreadyExists")
+    # We can create a sub cidr
+    client.create_route(
+        RouteTableId=main_route_table.id,
+        DestinationCidrBlock=ROUTE_SUB_CIDR,
+        GatewayId=igw.id,
+    )
+    # Or even a catch-all
+    client.create_route(
+        RouteTableId=main_route_table.id,
+        DestinationCidrBlock="0.0.0.0/0",
+        GatewayId=igw.id,
+    )
 
 
 @mock_ec2