Fix to #32192 - Remove lookup of JsonTypeMapping via JsonElement #35788
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maumar
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maumar
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Mar 14, 2025
| /// <summary> | ||
| /// A type representing CLR type of the JsonTypeMapping. | ||
| /// </summary> | ||
| public class JsonClrType |
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name suggestions are welcome @dotnet/efteam
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Move it to .Storage and make the default constructor private.
My naming suggestion is JsonTypePlaceholder
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Pull Request Overview
This PR fixes issues with JSON type mapping by introducing a new dummy CLR type (JsonClrType) to replace usage of JsonElement in EFCore, preventing misleading exceptions on providers that don’t support weak-typed JSON.
- Introduces the JsonClrType dummy marker type.
- Updates various Relational, SqlServer, and Sqlite mapping files to use JsonClrType instead of JsonElement.
- Updates tests and scaffolding baselines accordingly.
Reviewed Changes
Copilot reviewed 13 out of 13 changed files in this pull request and generated no comments.
Show a summary per file
| File | Description |
|---|---|
| src/EFCore.Relational/Metadata/JsonClrType.cs | New type definition for JsonClrType as a CLR marker. |
| test/EFCore.Relational.Specification.Tests/Query/AdHocMiscellaneousQueryRelationalTestBase.cs | Added test to ensure a meaningful exception is thrown for a JsonElement property. |
| src/EFCore.Relational/Metadata/Internal/JsonColumnBase.cs | Changed default type mapping lookup from JsonElement to JsonClrType. |
| src/EFCore.SqlServer/Storage/Internal/SqlServerTypeMappingSource.cs | Modified type check for JSON mapping to use JsonClrType. |
| src/EFCore.Relational/Storage/JsonTypeMapping.cs | Updated comments and mapping references from JsonElement to a generic description. |
| src/EFCore.Relational/Metadata/Internal/JsonViewColumn.cs | Adjusted default store type mapping to use JsonClrType. |
| src/EFCore.Relational/Metadata/Internal/JsonColumn.cs | Replaced JsonElement with JsonClrType in default mapping lookup. |
| src/EFCore.Sqlite.Core/Storage/Internal/SqliteJsonTypeMapping.cs | Changed constructor parameter and mapping type to JsonClrType. |
| src/EFCore.Sqlite.Core/Storage/Internal/SqliteTypeMappingSource.cs | Updated mapping dictionary entry from JsonElement to JsonClrType. |
| src/EFCore.SqlServer/Storage/Internal/SqlServerOwnedJsonTypeMapping.cs | Adjusted base constructor call to use JsonClrType. |
| test/EFCore.SqlServer.FunctionalTests/Scaffolding/Baselines/BigModel_with_JSON_columns/DbContextModelBuilder.cs | Updated generic column accessors to reference JsonClrType. |
| src/EFCore.Relational/Metadata/Internal/RelationalModel.cs | Changed lookup in relation to JSON column type mapping to use JsonClrType. |
| test/EFCore.Sqlite.FunctionalTests/Scaffolding/Baselines/BigModel_with_JSON_columns/DbContextModelBuilder.cs | Updated generic column accessors to reference JsonClrType. |
maumar
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Mar 14, 2025
...te.FunctionalTests/Scaffolding/Baselines/BigModel_with_JSON_columns/DbContextModelBuilder.cs
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AndriySvyryd
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Mar 14, 2025
When adding support for JSON mapped types, we decided to use JsonElement as a CLR type marker for JsonTypeMapping. This decision was in hindsight incorrect, it makes it hard for providers that actually support weak-typed json (npgsql) and throws cryptic exception (No coercion operator is defined between types 'System.IO.MemoryStream' and 'System.Text.Json.JsonElement) for providers that don't support it, when customers try to do it regardless. Fix is to create a dummy type and use that instead, so JsonElement is no longer recognized by base EFCore. Fixes #32192 also fixes #34752
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When adding support for JSON mapped types, we decided to use JsonElement as a CLR type marker for JsonTypeMapping. This decision was in hindsight incorrect, it makes it hard for providers that actually support weak-typed json (npgsql) and throws cryptic exception (No coercion operator is defined between types 'System.IO.MemoryStream' and 'System.Text.Json.JsonElement) for providers that don't support it, when customers try to do it regardless. Fix is to create a dummy type and use that instead, so JsonElement is no longer recognized by base EFCore.
Fixes #32192
also fixes #34752