Use null propagation to optimize away IS NOT NULL checks - #34127
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rebased to fix conflicts |
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@ranma42 Could you rebase on latest main? |
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Pull request overview
This PR improves relational query SQL generation by simplifying CASE expressions that merely replicate SQL’s built-in null propagation behavior, removing redundant IS NULL/IS NOT NULL checks and producing simpler SQL. This aligns with the null-semantics propagation optimization work tracked in #34126.
Changes:
- Added a
CASEsimplification inSqlNullabilityProcessor.VisitCaseto drop redundant null-checking when the result expression already null-propagates. - Updated multiple SQL Server/SQLite functional tests to reflect the simplified SQL (removing
CASEwrappers and redundant null predicates). - Added new null-semantics tests to validate the optimization scenarios (unary op, binary op, partial/nested/mixed checks).
Reviewed changes
Copilot reviewed 14 out of 14 changed files in this pull request and generated 2 comments.
Show a summary per file
| File | Description |
|---|---|
| src/EFCore.Relational/Query/SqlNullabilityProcessor.cs | Implements the CASE-to-null-propagating-expression simplification in the nullability processor. |
| test/EFCore.Relational.Specification.Tests/Query/NullSemanticsQueryTestBase.cs | Adds new relational-spec tests covering IS NOT NULL optimization scenarios. |
| test/EFCore.SqlServer.FunctionalTests/Query/NullSemanticsQuerySqlServerTest.cs | Adds SQL Server AssertSql baselines for the new null-semantics optimization tests. |
| test/EFCore.SqlServer.FunctionalTests/Query/GearsOfWarQuerySqlServerTest.cs | Updates expected SQL to remove redundant CASE null-propagation patterns. |
| test/EFCore.SqlServer.FunctionalTests/Query/TPTGearsOfWarQuerySqlServerTest.cs | Updates expected SQL to remove redundant CASE null-propagation patterns. |
| test/EFCore.SqlServer.FunctionalTests/Query/TPCGearsOfWarQuerySqlServerTest.cs | Updates expected SQL to remove redundant CASE null-propagation patterns. |
| test/EFCore.SqlServer.FunctionalTests/Query/TemporalGearsOfWarQuerySqlServerTest.cs | Updates expected SQL to remove redundant CASE null-propagation patterns (temporal queries). |
| test/EFCore.SqlServer.FunctionalTests/Query/TemporalComplexNavigationsCollectionsSharedTypeQuerySqlServerTest.cs | Updates expected SQL by removing redundant IS NOT NULL checks inside CASE projections. |
| test/EFCore.SqlServer.FunctionalTests/Query/NorthwindGroupByQuerySqlServerTest.cs | Simplifies aggregate SQL baseline (MAX([OrderDate]) instead of MAX(CASE ...)). |
| test/EFCore.SqlServer.FunctionalTests/Query/SpatialQuerySqlServerGeometryTest.cs | Removes redundant null-check CASE around SQL Server spatial instance method calls. |
| test/EFCore.SqlServer.FunctionalTests/Query/SpatialQuerySqlServerGeographyTest.cs | Removes redundant null-check CASE around SQL Server spatial instance method calls. |
| test/EFCore.SqlServer.FunctionalTests/Query/EntitySplittingQuerySqlServerTest.cs | Removes redundant IS NOT NULL checks in a projection CASE baseline. |
| test/EFCore.Sqlite.FunctionalTests/Query/GearsOfWarQuerySqliteTest.cs | Updates SQLite baselines to remove redundant CASE null-propagation patterns. |
| test/EFCore.Sqlite.FunctionalTests/Query/SpatialQuerySqliteTest.cs | Removes redundant null-check CASE around spatial function call baseline. |
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Sorry for the delay, I did not have much bandwidth to spare during the week. |
When a CASE expression simply replicates SQL null propagation, simplify it.
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When a CASE expression simply replicates SQL null propagation, simplify it.
Contributes to #34126.