Fix issues with nulls in primitive collections

[roji]

Fixes #37605

Thanks to @BurakBebek1 for flagging this and submitting a fix PR in #37600.

[Copilot]

Pull request overview

Fixes incorrect/null-unaware translation and execution for Contains over nullable primitive collections (especially when SQL Server switches to OPENJSON), ensuring correct matching of NULL elements and avoiding invalid nullable SqlExpression types.

Changes:

• Update relational null-stripping logic to preserve the original collection element CLR type when rewriting parameters (to keep value converters working correctly).
• Fix SQL Server OPENJSON ColumnExpression construction to use a non-nullable CLR type while keeping nullability in the separate nullable flag.
• Add/adjust provider functional tests (SqlServer/Sqlite/Cosmos) for EF.Parameter(...).Contains(...) and add large-collection regression coverage for #37605.

Reviewed changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
test/EFCore.Sqlite.FunctionalTests/Query/PrimitiveCollectionsQuerySqliteTest.cs	Adds SQL assertion for EF.Parameter + nullable ints including null semantics (OR ... IS NULL).
test/EFCore.SqlServer.FunctionalTests/Query/PrimitiveCollectionsQuerySqlServerTest.cs	Adds SQL assertion for OPENJSON + OR ... IS NULL, plus large collection regression test; file also appears to have gained a BOM.
test/EFCore.SqlServer.FunctionalTests/Query/PrimitiveCollectionsQuerySqlServerJsonTypeTest.cs	Adds SQL assertion for OPENJSON + OR ... IS NULL in JSON-type variant.
test/EFCore.SqlServer.FunctionalTests/Query/PrimitiveCollectionsQuerySqlServer160Test.cs	Adds SQL assertion for OPENJSON + OR ... IS NULL for SQL Server 2016+ coverage.
test/EFCore.SqlServer.FunctionalTests/Query/PrimitiveCollectionsQueryOldSqlServerTest.cs	Adds an override expecting EF.Parameter unsupported and adds a large-collection regression test.
test/EFCore.Specification.Tests/Query/PrimitiveCollectionsQueryTestBase.cs	Introduces new base test for EF.Parameter(nullableInts).Contains(...) with a null element.
test/EFCore.Cosmos.FunctionalTests/Query/PrimitiveCollectionsQueryCosmosTest.cs	Adds Cosmos SQL assertion for EF.Parameter over nullable ints including null.
src/EFCore.SqlServer/Query/Internal/SqlServerSqlNullabilityProcessor.cs	Ensures ColumnExpression type is non-nullable for OPENJSON projection; file also appears to have gained a BOM.
src/EFCore.Relational/Query/SqlNullabilityProcessor.cs	Rewrites null-stripping to pick element type from runtime IEnumerable<T> to preserve converter expectations.

[Copilot]

Pull request overview

Copilot reviewed 9 out of 9 changed files in this pull request and generated no new comments.

Comments suppressed due to low confidence (2)

test/EFCore.SqlServer.FunctionalTests/Query/PrimitiveCollectionsQuerySqlServerTest.cs:1

• This file now starts with a UTF-8 BOM (invisible character before the first //). Unless the file contains non-ASCII characters that require it, please revert the BOM/encoding-only change to avoid unnecessary diffs and inconsistent encodings across the repo.

// Licensed to the .NET Foundation under one or more agreements.

src/EFCore.SqlServer/Query/Internal/SqlServerSqlNullabilityProcessor.cs:1

• This file now starts with a UTF-8 BOM (invisible character before the license header). Unless there are non-ASCII characters in the file, please remove the BOM to avoid encoding-only churn and keep file encodings consistent.

// Licensed to the .NET Foundation under one or more agreements.