ref(crons): Add migration to backfill MonitorEnvironment.is_muted

[evanpurkhiser]

Implements Step 2 of the migration plan from NEW-564: There needs to be some way to mute the entire cron detector

This data migration backfills MonitorEnvironment.is_muted from Monitor.is_muted for all muted monitors. This ensures existing data is consistent before switching to read from MonitorEnvironment.is_muted.

After this migration runs:

• Monitors with is_muted=True will have ALL environments muted
• Monitors with is_muted=False will have environments unchanged

This establishes the correct invariant:

• Monitor is muted ↔ ALL environments are muted
• Monitor is unmuted ↔ ANY environment is unmuted

The migration:

• Uses range queries for efficient batching (1000 monitors per batch)
• Only updates environments for muted monitors (unmuted is the default)
• Is marked as post-deployment for manual execution in production

Test verifies:

• Muted monitor environments are updated to is_muted=True
• Unmuted monitor environments remain unchanged
• Monitors without environments are unaffected

[codecov]

❌ 1 Tests Failed:

Tests completed	Failed	Passed	Skipped
29770	1	29769	245

View the top 1 failed test(s) by shortest run time

tests.sentry.api.test_api_owners.APIOwnersTestCase::test_api_owner_is_a_valid_code_owner

Stack Traces | 0.049s run time

#x1B[1m#x1B[.../sentry/api/test_api_owners.py#x1B[0m:22: in test_api_owner_is_a_valid_code_owner
    assert owner.value in self.teams
#x1B[1m#x1B[31mE   AssertionError: assert 'visibility' in {'alerts-create-issues', 'alerts-notifications', 'codecov', 'crons', 'dashboards', 'data', ...}#x1B[0m
#x1B[1m#x1B[31mE    +  where 'visibility' = <ApiOwner.VISIBILITY: 'visibility'>.value#x1B[0m
#x1B[1m#x1B[31mE    +  and   {'alerts-create-issues', 'alerts-notifications', 'codecov', 'crons', 'dashboards', 'data', ...} = <tests.sentry.api.test_api_owners.APIOwnersTestCase testMethod=test_api_owner_is_a_valid_code_owner>.teams#x1B[0m

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[github-actions]

This PR has a migration; here is the generated SQL for src/sentry/monitors/migrations/0011_backfill_monitor_environment_is_muted.py

for 0011_backfill_monitor_environment_is_muted in monitors

--
-- Raw Python operation
--
-- THIS OPERATION CANNOT BE WRITTEN AS SQL

[wedamija]

You may as well just use RangeQuerySetWrapper and filter is_muted in memory. There's no index on id, is_muted so writing this manually won't help at all.

[evanpurkhiser]

look again

[wedamija]

You're better off filtering is_muted in memory here instead of the query, otherwise you might end up with timeouts.

[evanpurkhiser]

good call