Improve exception for JsonElement with Sqlite #34752
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In case it's helpful, here are copies of the code files: Program.cs using Microsoft.Data.Sqlite;
using Microsoft.EntityFrameworkCore;
using SqliteJsonTest;
await using var conn = new SqliteConnection(new SqliteConnectionStringBuilder
{
DataSource = ":memory:",
}.ConnectionString);
await conn.OpenAsync();
await using var db = new WidgetContext(new DbContextOptionsBuilder<WidgetContext>().UseSqlite(conn).Options);
await db.Database.EnsureCreatedAsync();
var widget = await db.Widgets.SingleAsync();WidgetContext.cs using Microsoft.EntityFrameworkCore;
namespace SqliteJsonTest;
internal sealed class WidgetContext : DbContext
{
public DbSet<Widget> Widgets { get; set; }
public WidgetContext(DbContextOptions options) : base(options)
{
}
}Widget.cs using System.Text.Json;
namespace SqliteJsonTest;
internal sealed class Widget
{
public long Id { get; set; }
public JsonElement Metadata { get; set; }
}SqliteJsonTest.csproj <Project Sdk="Microsoft.NET.Sdk">
<PropertyGroup>
<OutputType>Exe</OutputType>
<TargetFramework>net8.0</TargetFramework>
<ImplicitUsings>enable</ImplicitUsings>
<Nullable>enable</Nullable>
</PropertyGroup>
<ItemGroup>
<PackageReference Include="Microsoft.EntityFrameworkCore.Sqlite" Version="8.0.8" />
</ItemGroup>
</Project> |
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related to / dupe of #28871 we could consider throwing a better exception in the meantime |
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@maumar using Microsoft.EntityFrameworkCore.Sqlite 7.0.20, I get |
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yeah, we should get back to something similar. Looks like we bypass any validation and try to construct the shaper for JsonElement as if it were a regular POCO entity mapped to json (and resulting in nasty error about MemoryStream). We do use clr type |
AndriySvyryd
changed the title
maumar
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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
maumar
added a commit
that referenced
this issue
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
maumar
added a commit
that referenced
this issue
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
maumar
added a commit
that referenced
this issue
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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Getting exception
System.InvalidOperationException: 'No coercion operator is defined between types 'System.IO.MemoryStream' and 'System.Text.Json.JsonElement'.'when trying to pull back records withJsonElementproperties.Stacktrace:
Code is here:
SqliteJsonTest.zip
EF Core version: 8.0.8
Database provider: Microsoft.EntityFrameworkCore.Sqlite
Target framework: .NET 8.0
Operating system: Windows 10 Enterprise 22H2
IDE: Visual Studio 2022 17.11.4
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