Add Optimized Single Column Date Rewriter

[mikaelweave]

Description

• Adds an allow-listed SQL scalar-temporal equality rewriter for Patient.birthdate.
• Rewrites exact-day and exact-year equality searches to use DateTimeEnd predicates while preserving existing handling for month precision, ranges, composites, and non-allow-listed date parameters.
• Adds focused unit coverage for the rewrite behavior and includes the current partial-birthdate E2E baseline from the test PR.

Related issues

AB#190492

Testing

Describe how this change was tested.

FHIR Team Checklist

• Update the title of the PR to be succinct and less than 65 characters
• Add a milestone to the PR for the sprint that it is merged (i.e. add S47)
• Tag the PR with the type of update: Bug, Build, Dependencies, Enhancement, New-Feature or Documentation
• Tag the PR with Open source, Azure API for FHIR (CosmosDB or common code) or Azure Healthcare APIs (SQL or common code) to specify where this change is intended to be released.
• Tag the PR with Schema Version backward compatible or Schema Version backward incompatible or Schema Version unchanged if this adds or updates Sql script which is/is not backward compatible with the code.
• When changing or adding behavior, if your code modifies the system design or changes design assumptions, please create and include an ADR.
• CI is green before merge
• Review squash-merge requirements

Semver Change (docs)

Patch|Skip|Feature|Breaking (reason)

[brendankowitz]

🤖 Automated Pipeline Failure Analysis — Build #49384

❌ Failed Jobs

Job	Result
Run R4 Cosmos Tests cosmosE2eTests	❌ Failed
Run Stu3 Cosmos Tests cosmosE2eTests	❌ Failed
All SQL E2E tests (R4, R5, Stu3)	✅ Passed
All unit tests & integration tests	✅ Passed

Root Cause

The ScalarTemporalEqualityRewriter was registered in the SQL Server search pipeline (SqlServerSearchService.cs, line ~2062), but the Cosmos DB search pipeline (FhirCosmosSearchService.cs, lines 78-84) still uses only:

compartmentSearchRewriter,
smartCompartmentSearchRewriter,
DateTimeEqualityRewriter.Instance,

The shared E2E test GivenPatientsWithPartialBirthdates_WhenSearchedByEquality_ThenCurrentOverlapBehaviorIsPreserved in DateSearchTests.cs was updated to expect the tighter day-precision results (e.g. dayBundle → only patient2000March03), which is correct for SQL where the rewriter is active. However, Cosmos DB still returns the old overlap-based results (patient2000, patient2000March, patient2000March03), causing both Cosmos E2E test jobs to fail.

Suggested Fix

Since the test class is decorated with [HttpIntegrationFixtureArgumentSets(DataStore.All, Format.Json)] and extends SearchTestsBase<DateSearchTestFixture>, the Fixture.DataStore property is available to branch assertions by backend. For example:

Bundle dayBundle = await Client.SearchAsync(ResourceType.Patient, $"birthdate=2000-03-03&_tag={tag}");
if (Fixture.DataStore == DataStore.SqlServer)
{
    // SQL path: ScalarTemporalEqualityRewriter narrows to exact-day containment
    ValidateBundle(dayBundle, patient2000March03);
}
else
{
    // Cosmos path: still uses range overlap (tracked by AB#191826)
    ValidateBundle(dayBundle, patient2000, patient2000March, patient2000March03);
}

Apply the same pattern for the lastDayBundle assertion.

Alternatively, the rewriter could be added to the Cosmos DB pipeline too, but ScalarTemporalEqualityRewriter uses SQL-specific constructs (SqlFieldName.DateTimeIsLongerThanADay), so that would require additional Cosmos DB query model work.

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Analysis by Azure SRE Agent