Obsolete owned JSON entities in relational

[roji]

Closes #37290

[AndriySvyryd]

File an issue to remove the obsoletion before RC2 so we don't forget

[Copilot]

Pull request overview

This pull request obsoletes the ToJson() method for owned JSON entities in EF Core's relational functionality, encouraging developers to migrate to complex types for JSON mapping instead. The change introduces a new diagnostic code (EF8001) and adds #pragma warning disable/restore directives throughout the test suite to suppress warnings for existing usage of the obsolete API.

Key Changes:

• Added [Obsolete] attributes to ToJson() extension methods with diagnostic ID EF8001
• Introduced diagnostic constants in EFDiagnostics.cs for the obsolete owned JSON entities feature
• Suppressed EF8001 warnings across test files that continue to test the now-obsolete functionality

Reviewed changes

Copilot reviewed 31 out of 31 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
src/Shared/EFDiagnostics.cs	Added constants for EF8001 diagnostic and obsolete message for owned JSON entities
src/EFCore.Relational/Extensions/RelationalOwnedNavigationBuilderExtensions.cs	Marked four ToJson() overloads as obsolete with diagnostic ID EF8001
test/EFCore.Specification.Tests/TestUtilities/BuildSource.cs	Configured compiler to suppress EF8001 warnings in dynamically compiled test code
test/EFCore.Tests/Infrastructure/ModelValidatorTest.cs	Added pragma directives to suppress EF8001 warnings for owned entity type tests
test/EFCore.Relational.Tests/Infrastructure/RelationalModelValidatorTest.Json.cs	Added file-level pragma to suppress warnings for JSON validation tests
test/EFCore.Relational.Tests/Migrations/Internal/MigrationsModelDifferTest.cs	Wrapped owned-to-complex conversion test with pragma directives
test/EFCore.Relational.Tests/Metadata/Conventions/TableSharingConcurrencyTokenConventionTest.cs	Added pragma directives around JSON-mapped entity test
test/EFCore.Relational.Specification.Tests/Update/JsonUpdateFixtureBase.cs	Added file-level pragma to suppress warnings for JSON update test fixtures
test/EFCore.Relational.Specification.Tests/Query/JsonQueryRelationalFixture.cs	Added file-level pragma to suppress warnings for JSON query fixtures
test/EFCore.Relational.Specification.Tests/Query/PrecompiledQueryRelationalTestBase.cs	Wrapped OnModelCreating method with pragma directives for JSON entity configuration
test/EFCore.Relational.Specification.Tests/Query/OptionalDependentQueryFixtureBase.cs	Wrapped OnModelCreating method with pragma directives for JSON entity setup
test/EFCore.Relational.Specification.Tests/Query/OperatorsQueryTestBase.cs	Added pragma directives around JSON scalar concatenation test
test/EFCore.Relational.Specification.Tests/Query/NonSharedPrimitiveCollectionsQueryRelationalTestBase.cs	Wrapped column collection test with pragma directives
test/EFCore.Relational.Specification.Tests/Query/AdHocPrecompiledQueryRelationalTestBase.cs	Added pragma directives around JsonContext class definition
test/EFCore.Relational.Specification.Tests/Query/AdHocJsonQueryRelationalTestBase.cs	Added file-level pragma to suppress warnings for ad-hoc JSON query tests
test/EFCore.Relational.Specification.Tests/Query/Associations/OwnedJson/OwnedJsonRelationalFixtureBase.cs	Added file-level pragma to suppress warnings in owned JSON association tests
test/EFCore.Relational.Specification.Tests/Scaffolding/CompiledModelRelationalTestBase.cs	Added pragma directives around ToJson() calls in conditional blocks
test/EFCore.Relational.Specification.Tests/PropertyValuesRelationalTestBase.cs	Added file-level pragma to suppress warnings for property values tests
test/EFCore.Relational.Specification.Tests/ModelBuilding/RelationalTestModelBuilderExtensions.cs	Marked test helper ToJson() extension methods as obsolete with diagnostic ID
test/EFCore.Relational.Specification.Tests/Migrations/MigrationsTestBase.cs	Added pragma directives around multiple JSON-related migration tests
test/EFCore.Relational.Specification.Tests/ComplexTypesTrackingRelationalTestBase.cs	Wrapped OnModelCreating method with pragma directives for JSON entity configuration
test/EFCore.SqlServer.Tests/Infrastructure/SqlServerModelValidatorTest.cs	Renamed test method and added pragma directives for vector inside JSON owned entity test
test/EFCore.SqlServer.Tests/Migrations/SqlServerModelDifferTest.cs	Added pragma directives around column type alteration tests for owned types
test/EFCore.SqlServer.FunctionalTests/Update/JsonUpdateJsonTypeSqlServerFixture.cs	Added file-level pragma to suppress warnings for SQL Server JSON update tests
test/EFCore.SqlServer.FunctionalTests/Query/JsonQueryJsonTypeSqlServerFixture.cs	Added file-level pragma to suppress warnings for SQL Server JSON query tests
test/EFCore.SqlServer.FunctionalTests/Query/AdHocMiscellaneousQuerySqlServerTest.cs	Wrapped OnModelCreating method with pragma directives for context setup
test/EFCore.SqlServer.FunctionalTests/Query/AdHocJsonQuerySqlServerTestBase.cs	Added file-level pragma to suppress warnings for SQL Server ad-hoc JSON tests
test/EFCore.SqlServer.FunctionalTests/ModelBuilding/SqlServerModelBuilderTestBase.cs	Added pragma directives around multiple JSON entity tests with nested restore directive
test/EFCore.SqlServer.FunctionalTests/MaterializationInterceptionSqlServerTest.cs	Wrapped OnModelCreating method with pragma directives for owned JSON entity setup
test/EFCore.Sqlite.FunctionalTests/MaterializationInterceptionSqliteTest.cs	Wrapped OnModelCreating method with pragma directives for owned JSON entity configuration
test/EFCore.Design.Tests/Migrations/Design/CSharpMigrationsGeneratorTest.ModelSnapshot.cs	Added pragma directives around JSON snapshot storage tests

[roji]

File an issue to remove the obsoletion before RC2 so we don't forget

I've reopened #37290 and it's still in the 11 milestone; we can use it both to gather feedback and to remember to revisit the question.