fix: allow null materialization in ModelAlertDataSchema for ClickHouse compatibility

[devin-ai-integration]

Summary

Fixes a ValidationError (none is not an allowed value) when running edr monitor against ClickHouse, where the materialization column in alerts_v2 can be NULL.

ModelAlertDataSchema.materialization was typed as str (required, non-nullable). When ClickHouse returns null for this field, Pydantic v1 rejects it during PendingAlertSchema construction. This changes it to Optional[str] = None in both the Pydantic schema and the downstream ModelAlertModel, and handles None in the summary property string formatting.

Downstream code (slack.py, builder.py, base_integration.py) already guards against falsy materialization with truthiness checks or == "snapshot" comparisons, so no additional changes were needed there.

Review & Testing Checklist for Human

• Parameter reorder in ModelAlertModel.__init__: materialization was moved after alert_class_id to satisfy Python's rule that default-valued params follow non-default ones. Verify no callers pass materialization positionally (grep for ModelAlertModel( — existing callers in format_alert and test utilities use keyword args, but confirm nothing was missed).
• concise_name with null materialization: When materialization is None, concise_name will default to "model" (since None == "snapshot" is False). Confirm this is the desired fallback behavior rather than e.g. "unknown".
• Ideally, reproduce with a ClickHouse instance that has a NULL materialization row in alerts_v2 and confirm edr monitor no longer crashes.

Notes

• The root cause is that ClickHouse can store NULL for the materialization column when a model's materialization metadata is unavailable. Other warehouses may populate this field more reliably, which is why this hasn't surfaced outside ClickHouse.
• Existing unit tests (26 tests across alert schemas, pending alerts, and model alert messages) all pass with these changes.

Link to Devin session: https://app.devin.ai/sessions/362d19b8c47b47dd9b895f512ffdd30f
Requested by: @arbiv

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Summary by CodeRabbit

• Bug Fixes
  • Model alerts now support scenarios where materialization information is unavailable. Alert summaries are generated gracefully when this data is missing.

[devin-ai-integration]

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Thank you for raising your pull request.
Please make sure to add tests and document all user-facing changes.
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📝 Walkthrough

Walkthrough

Two files updated to make the materialization field optional in model alert definitions. The ModelAlertModel summary property was adjusted to conditionally include materialization when present.

Changes

Cohort / File(s)	Summary
Making materialization optional elementary/monitor/alerts/model_alert.py, elementary/monitor/fetchers/alerts/schema/alert_data.py	Updated materialization parameter from required str to Optional[str] = None in both the data schema and model. Adjusted ModelAlertModel.summary to conditionally include materialization text only when the value is present.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~8 minutes

Poem

🐰 A field once rigid, now set free,
Optional it shall come to be—
When missing, the message adapts with grace,
Flexibility finds its perfect place! ✨

🚥 Pre-merge checks | ✅ 2 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and specifically summarizes the main change: making materialization optional in ModelAlertDataSchema to support ClickHouse compatibility.
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.

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✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch devin/1775713161-fix-nullable-materialization

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[devin-ai-integration]

Devin Review found 1 potential issue.

View 3 additional findings in Devin Review.

[devin-ai-integration]

🟡 concise_name not updated to handle None materialization, unlike summary

The summary property was updated (lines 113-115) to gracefully handle materialization=None, but the concise_name property (lines 104-109) was not. When materialization is None, concise_name falls through to the else branch and returns "dbt model alert - {alias}", which may be incorrect (e.g., if the resource is a snapshot whose materialization data is missing). The same pattern also exists at elementary/monitor/alerts/alert_messages/builder.py:195 (asset_type = "snapshot" if alert.materialization == "snapshot" else "model"), which was also not updated.

(Refers to lines 104-109)

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[devin-ai-integration]

This is intentional behavior. When materialization is None, falling through to the else branch and defaulting to "model" is the correct safe fallback. The same pattern at builder.py:195 also defaults to "model" for the same reason.

A snapshot whose materialization metadata is missing would be an unusual edge case — in practice, if a snapshot is correctly configured in dbt, its materialization field would be populated as "snapshot". The scenario triggering this bug is model alerts in ClickHouse where the materialization column is NULL due to missing metadata, and defaulting those to "model" is the appropriate behavior.

The summary property was updated differently because it interpolates materialization directly into the string (which would produce "dbt failed to build None "alias""), while concise_name only checks equality against "snapshot" and never renders the raw value.