[rc2] Fix DefaultIfEmpty and nullability within SelectMany selector #36238
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June 23, 2025 21:09
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| Assert.Equal( | ||
| CoreStrings.ExpressionParameterizationExceptionSensitive( | ||
| "value(Microsoft.EntityFrameworkCore.Query.NorthwindMiscellaneousQueryTestBase`1+<>c__DisplayClass175_0[Microsoft.EntityFrameworkCore.Query.NorthwindQueryCosmosFixture`1[Microsoft.EntityFrameworkCore.TestUtilities.NoopModelCustomizer]]).ss.Set().Any()"), | ||
| "value(Microsoft.EntityFrameworkCore.Query.NorthwindMiscellaneousQueryTestBase`1+<>c__DisplayClass177_0[Microsoft.EntityFrameworkCore.Query.NorthwindQueryCosmosFixture`1[Microsoft.EntityFrameworkCore.TestUtilities.NoopModelCustomizer]]).ss.Set().Any()"), |
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Consider using Contains to avoid having a compiler-generated string in the assert
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What makes this slightly tricky is that the compiler-generated component is integrated inside the CoreStrings template etc... If it starts happening frequently we can think about a better way...
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Fixes #35950
Description
See #35950 (comment) for a detailed explanation of what's going on. tl;dr a COALESCE optimization done in 9.0 exposed a previously-existing, latent bug with columns not being considered nullable though they're after DefaultIfEmpty.
Customer impact
Some queries involving the DefaultIfEmpty() operator which worked in EF 8.0 started failing in EF 9.0.
Note that various other bugfixes to DefaultIfEmpty have been done in 10.0 (#36208, #33343, #19095) - this continues those fixes to substantially improve DefaultIfEmpty support in general.
How found
User-reported
Regression
Yes, from 8.0 to 9.0.
Testing
Added
Risk
Low, targeted fix for the specific scenario.