fix: allow null materialization in ModelAlertDataSchema for ClickHouse compatibility (#2180)

When ClickHouse stores NULL for the materialization column in alerts_v2,
the JSON data contains "materialization": null. The Pydantic schema
rejected this with 'none is not an allowed value' because materialization
was typed as str (required, non-nullable).

This change makes materialization Optional[str] in both the schema and
the alert model, and handles None gracefully in string formatting.

Co-authored-by: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
Co-authored-by: Yosef Arbiv <yosef.arbiv@gmail.com>

Author: devin-ai-integration[bot]

elementary/monitor/alerts/model_alert.py

@@ -18,9 +18,9 @@ def __init__(
         alias: str,
         path: str,
         original_path: str,
-        materialization: str,
         full_refresh: bool,
         alert_class_id: str,
+        materialization: Optional[str] = None,
         message: Optional[str] = None,
         model_unique_id: Optional[str] = None,
         detected_at: Optional[datetime] = None,
@@ -110,7 +110,9 @@ def concise_name(self) -> str:
 
     @property
     def summary(self) -> str:
-        return f'dbt failed to build {self.materialization} "{self.alias}"'
+        if self.materialization:
+            return f'dbt failed to build {self.materialization} "{self.alias}"'
+        return f'dbt failed to build "{self.alias}"'
 
     def get_report_link(self) -> Optional[ReportLinkData]:
         return get_model_runs_link(self.report_url, self.model_unique_id)

elementary/monitor/fetchers/alerts/schema/alert_data.py

@@ -249,7 +249,7 @@ class ModelAlertDataSchema(BaseAlertDataSchema):
     alias: str
     path: str
     original_path: str
-    materialization: str
+    materialization: Optional[str] = None
     full_refresh: bool
     message: Optional[str] = None
     resource_type: ResourceType = Field(ResourceType.MODEL, const=True)  # type: ignore  # noqa