fix: the exception of plan validation (#714)

* fix: Missing Required Fields in Plan Validation

* fix: the exception of plan validation

* Fixed the test errors

* Addressed the comments of the PR reviews

tests/unit/graph/test_plan_validation.py

@@ -167,8 +167,8 @@ class TestValidateAndFixPlanStepTypeRepair:
             validate_and_fix_plan(plan)
             # Should log repair operation
             mock_logger.info.assert_called()
-            call_args = str(mock_logger.info.call_args)
-            assert "Repaired missing step_type" in call_args
+            # Check that any of the info calls contains "Repaired missing step_type"
+            assert any("Repaired missing step_type" in str(call) for call in mock_logger.info.call_args_list)
 
     def test_non_dict_plan_returns_unchanged(self):
         """Test that non-dict plans are returned unchanged."""
@@ -363,6 +363,154 @@ class TestValidateAndFixPlanIntegration:
         assert result["steps"][1]["need_search"] is False
 
 
+class TestValidateAndFixPlanIssue710:
+    """Specific tests for Issue #710 scenarios - missing required Plan fields."""
+
+    def test_missing_locale_field_added(self):
+        """Test that missing locale field is added with default value."""
+        plan = {
+            "has_enough_context": True,
+            "title": "Test Plan",
+            "steps": []
+        }
+
+        result = validate_and_fix_plan(plan)
+
+        assert "locale" in result
+        assert result["locale"] == "en-US"
+
+    def test_empty_locale_field_replaced(self):
+        """Test that empty locale field is replaced with default value."""
+        plan = {
+            "locale": "",
+            "has_enough_context": True,
+            "title": "Test Plan",
+            "steps": []
+        }
+
+        result = validate_and_fix_plan(plan)
+
+        assert "locale" in result
+        assert result["locale"] == "en-US"
+
+    def test_missing_has_enough_context_field_added(self):
+        """Test that missing has_enough_context field is added with default value."""
+        plan = {
+            "locale": "en-US",
+            "title": "Test Plan",
+            "steps": []
+        }
+
+        result = validate_and_fix_plan(plan)
+
+        assert "has_enough_context" in result
+        assert result["has_enough_context"] is False
+
+    def test_missing_title_field_added_from_step(self):
+        """Test that missing title field is inferred from first step."""
+        plan = {
+            "locale": "en-US",
+            "has_enough_context": True,
+            "steps": [
+                {
+                    "need_search": True,
+                    "title": "Step Title",
+                    "description": "Step description",
+                    "step_type": "research"
+                }
+            ]
+        }
+
+        result = validate_and_fix_plan(plan)
+
+        assert "title" in result
+        assert result["title"] == "Step Title"
+
+    def test_missing_title_field_added_default(self):
+        """Test that missing title field is added with default when no steps available."""
+        plan = {
+            "locale": "en-US",
+            "has_enough_context": True,
+            "steps": []
+        }
+
+        result = validate_and_fix_plan(plan)
+
+        assert "title" in result
+        assert result["title"] == "Research Plan"
+
+    def test_all_required_fields_missing(self):
+        """Test that all missing required fields are added."""
+        plan = {
+            "steps": [
+                {
+                    "need_search": True,
+                    "title": "Step 1",
+                    "description": "Description",
+                    "step_type": "research"
+                }
+            ]
+        }
+
+        result = validate_and_fix_plan(plan)
+
+        # All required fields should be present
+        assert "locale" in result
+        assert "has_enough_context" in result
+        assert "title" in result
+
+        # With appropriate defaults
+        assert result["locale"] == "en-US"
+        assert result["has_enough_context"] is False
+        assert result["title"] == "Step 1"  # Inferred from first step
+
+    def test_issue_710_scenario_passes_pydantic_validation(self):
+        """Test that fixed plan can be validated by Pydantic schema (reproduces issue #710 fix)."""
+        from src.prompts.planner_model import Plan as PlanModel
+
+        # Simulate the problematic plan from issue #710 that's missing required fields
+        plan = {
+            "content": '{\n  "locale": "en-US",\n  "has_enough_context": false,\n  "title": "Test Plan",\n  "steps": [\n    {\n      "need_search": true,\n      "title": "Research Step",\n      "description": "Gather data",\n      "step_type": "research"\n    }\n  ]\n}',
+            "reasoning": 2368
+        }
+
+        # Extract just the JSON part (simulating what would happen in the actual flow)
+        import json
+        json_content = json.loads(plan["content"])
+
+        # Remove required fields to simulate the issue
+        del json_content["locale"]
+        del json_content["has_enough_context"]
+        del json_content["title"]
+
+        # First validate and fix
+        fixed_plan = validate_and_fix_plan(json_content)
+
+        # Then try Pydantic validation (should not raise)
+        validated = PlanModel.model_validate(fixed_plan)
+
+        # Validation should succeed
+        assert validated.locale == "en-US"
+        assert validated.has_enough_context is False
+        assert validated.title == "Research Step"  # Inferred from first step
+
+    def test_existing_fields_preserved(self):
+        """Test that existing valid fields are preserved."""
+        plan = {
+            "locale": "zh-CN",
+            "has_enough_context": True,
+            "title": "Existing Title",
+            "steps": []
+        }
+
+        result = validate_and_fix_plan(plan)
+
+        # Existing values should be preserved
+        assert result["locale"] == "zh-CN"
+        assert result["has_enough_context"] is True
+        assert result["title"] == "Existing Title"
+
+
 class TestValidateAndFixPlanIssue650:
     """Specific tests for Issue #650 scenarios."""