error on conflicts

dimos/core/blueprints.py

@@ -110,6 +110,41 @@ def _all_name_types(self) -> set[tuple[str, type]]:
     def _is_name_unique(self, name: str) -> bool:
         return sum(1 for n, _ in self._all_name_types if n == name) == 1
 
+    def _verify_no_name_conflicts(self) -> None:
+        name_to_types = defaultdict(set)
+        name_to_modules = defaultdict(list)
+
+        for blueprint in self.blueprints:
+            for conn in blueprint.connections:
+                connection_name = self.remapping_map.get((blueprint.module, conn.name), conn.name)
+                name_to_types[connection_name].add(conn.type)
+                name_to_modules[connection_name].append((blueprint.module, conn.type))
+
+        conflicts = {}
+        for conn_name, types in name_to_types.items():
+            if len(types) > 1:
+                modules_by_type = defaultdict(list)
+                for module, conn_type in name_to_modules[conn_name]:
+                    modules_by_type[conn_type].append(module)
+                conflicts[conn_name] = modules_by_type
+
+        if not conflicts:
+            return
+
+        error_lines = ["Blueprint cannot start because there are conflicting connections."]
+        for name, modules_by_type in conflicts.items():
+            type_entries = []
+            for conn_type, modules in modules_by_type.items():
+                for module in modules:
+                    type_str = f"{conn_type.__module__}.{conn_type.__name__}"
+                    module_str = module.__name__
+                    type_entries.append((type_str, module_str))
+            if len(type_entries) >= 2:
+                locations = ", ".join(f"{type_} in {module}" for type_, module in type_entries)
+                error_lines.append(f"    - '{name}' has conflicting types. {locations}")
+
+        raise ValueError("\n".join(error_lines))
+
     def _deploy_all_modules(
         self, module_coordinator: ModuleCoordinator, global_config: GlobalConfig
     ) -> None:
@@ -209,6 +244,8 @@ def build(self, global_config: GlobalConfig | None = None) -> ModuleCoordinator:
             global_config = GlobalConfig()
         global_config = global_config.model_copy(update=self.global_config_overrides)
 
+        self._verify_no_name_conflicts()
+
         module_coordinator = ModuleCoordinator(global_config=global_config)
         module_coordinator.start()
 

dimos/core/test_blueprints.py

@@ -12,6 +12,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import pytest
+
 from dimos.core.blueprints import (
     ModuleBlueprint,
     ModuleBlueprintSet,
@@ -185,6 +187,81 @@ def test_build_happy_path() -> None:
         coordinator.stop()
 
 
+def test_name_conflicts_are_reported() -> None:
+    class ModuleA(Module):
+        shared_data: Out[Data1] = None
+
+    class ModuleB(Module):
+        shared_data: In[Data2] = None
+
+    blueprint_set = autoconnect(ModuleA.blueprint(), ModuleB.blueprint())
+
+    try:
+        blueprint_set._verify_no_name_conflicts()
+        pytest.fail("Expected ValueError to be raised")
+    except ValueError as e:
+        error_message = str(e)
+        assert "Blueprint cannot start because there are conflicting connections" in error_message
+        assert "'shared_data' has conflicting types" in error_message
+        assert "Data1 in ModuleA" in error_message
+        assert "Data2 in ModuleB" in error_message
+
+
+def test_multiple_name_conflicts_are_reported() -> None:
+    class Module1(Module):
+        sensor_data: Out[Data1] = None
+        control_signal: Out[Data2] = None
+
+    class Module2(Module):
+        sensor_data: In[Data2] = None
+        control_signal: In[Data3] = None
+
+    blueprint_set = autoconnect(Module1.blueprint(), Module2.blueprint())
+
+    try:
+        blueprint_set._verify_no_name_conflicts()
+        pytest.fail("Expected ValueError to be raised")
+    except ValueError as e:
+        error_message = str(e)
+        assert "Blueprint cannot start because there are conflicting connections" in error_message
+        assert "'sensor_data' has conflicting types" in error_message
+        assert "'control_signal' has conflicting types" in error_message
+
+
+def test_that_remapping_can_resolve_conflicts() -> None:
+    class Module1(Module):
+        data: Out[Data1] = None
+
+    class Module2(Module):
+        data: Out[Data2] = None  # Would conflict with Module1.data
+
+    class Module3(Module):
+        data1: In[Data1] = None
+        data2: In[Data2] = None
+
+    # Without remapping, should raise conflict error
+    blueprint_set = autoconnect(Module1.blueprint(), Module2.blueprint(), Module3.blueprint())
+
+    try:
+        blueprint_set._verify_no_name_conflicts()
+        pytest.fail("Expected ValueError due to conflict")
+    except ValueError as e:
+        assert "'data' has conflicting types" in str(e)
+
+    # With remapping to resolve the conflict
+    blueprint_set_remapped = autoconnect(
+        Module1.blueprint(), Module2.blueprint(), Module3.blueprint()
+    ).remappings(
+        [
+            (Module1, "data", "data1"),
+            (Module2, "data", "data2"),
+        ]
+    )
+
+    # Should not raise any exception after remapping
+    blueprint_set_remapped._verify_no_name_conflicts()
+
+
 def test_remapping() -> None:
     """Test that remapping connections works correctly."""
     pubsub.lcm.autoconf()

dimos/robot/all_blueprints.py

@@ -37,6 +37,7 @@
     "demo-google-maps-skill": "dimos.agents2.skills.demo_google_maps_skill:demo_google_maps_skill",
     "demo-remapping": "dimos.robot.unitree_webrtc.demo_remapping:remapping",
     "demo-remapping-transport": "dimos.robot.unitree_webrtc.demo_remapping:remapping_and_transport",
+    "demo-error-on-name-conflicts": "dimos.robot.unitree_webrtc.demo_error_on_name_conflicts:blueprint",
 }
 
 

dimos/robot/unitree_webrtc/demo_error_on_name_conflicts.py

@@ -0,0 +1,53 @@
+# Copyright 2025 Dimensional Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from dimos.core.blueprints import autoconnect
+from dimos.core.core import rpc
+from dimos.core.module import Module
+from dimos.core.stream import In, Out
+
+
+class Data1:
+    pass
+
+
+class Data2:
+    pass
+
+
+class ModuleA(Module):
+    shared_data: Out[Data1] = None
+
+    @rpc
+    def start(self) -> None:
+        super().start()
+
+    @rpc
+    def stop(self) -> None:
+        super().stop()
+
+
+class ModuleB(Module):
+    shared_data: In[Data2] = None
+
+    @rpc
+    def start(self) -> None:
+        super().start()
+
+    @rpc
+    def stop(self) -> None:
+        super().stop()
+
+
+blueprint = autoconnect(ModuleA.blueprint(), ModuleB.blueprint())