Cannot generate compiled model on EFCore.PG with an array value converter

[JustArchi]

File a bug

Hey, the below worked fine in EF Core 7 (.NET 7). After update to 8.0.0, it now gives error during dotnet ef dbcontext optimize. Naturally I stumbled upon this in my own real project, but I've extracted minimal reproducible case that should make you run into the issue.

Include your code

[Table("test")]
public sealed class Asset {
	[Column]
	[Key]
	public int ID { get; set; }
	
	[Column]
	public List<EType> MatchableTypes { get; set; } = new();
}

public enum EType {
	Unknown,
	One,
	Two
}

public sealed class MyContext : DbContext {
	public DbSet<Asset> Assets => Set<Asset>();

	public MyContext(DbContextOptions<MyContext> options) : base(options) { }
}

Include stack traces

System.ArgumentOutOfRangeException: Specified argument was out of the range of valid values.
   at Microsoft.CodeAnalysis.CSharp.SyntaxFactory.GetBinaryExpressionOperatorTokenKind(SyntaxKind kind)
   at Microsoft.CodeAnalysis.CSharp.SyntaxFactory.BinaryExpression(SyntaxKind kind, ExpressionSyntax left, ExpressionSyntax right)
   at Microsoft.EntityFrameworkCore.Query.Internal.LinqToCSharpSyntaxTranslator.VisitBinary(BinaryExpression binary)
   at Microsoft.EntityFrameworkCore.Query.Internal.LinqToCSharpSyntaxTranslator.Visit(Expression node)
   at Microsoft.EntityFrameworkCore.Query.Internal.LinqToCSharpSyntaxTranslator.Translate(Expression node)
   at Microsoft.EntityFrameworkCore.Query.Internal.LinqToCSharpSyntaxTranslator.VisitBlock(BlockExpression block)
   at Microsoft.EntityFrameworkCore.Query.Internal.LinqToCSharpSyntaxTranslator.Visit(Expression node)
   at Microsoft.EntityFrameworkCore.Query.Internal.LinqToCSharpSyntaxTranslator.Translate(Expression node)
   at Microsoft.EntityFrameworkCore.Query.Internal.LinqToCSharpSyntaxTranslator.<TranslateConditional>g__TranslateConditionalStatement|35_0(ConditionalExpression conditional, <>c__DisplayClass35_0&)
   at Microsoft.EntityFrameworkCore.Query.Internal.LinqToCSharpSyntaxTranslator.TranslateConditional(ConditionalExpression conditional, IdentifierNameSyntax lowerableAssignmentVariable)
   at Microsoft.EntityFrameworkCore.Query.Internal.LinqToCSharpSyntaxTranslator.VisitConditional(ConditionalExpression conditional)
   at Microsoft.EntityFrameworkCore.Query.Internal.LinqToCSharpSyntaxTranslator.Visit(Expression node)
   at Microsoft.EntityFrameworkCore.Query.Internal.LinqToCSharpSyntaxTranslator.Translate(Expression node)
   at Microsoft.EntityFrameworkCore.Query.Internal.LinqToCSharpSyntaxTranslator.VisitLoop(LoopExpression loop)
   at Microsoft.EntityFrameworkCore.Query.Internal.LinqToCSharpSyntaxTranslator.Visit(Expression node)
   at Microsoft.EntityFrameworkCore.Query.Internal.LinqToCSharpSyntaxTranslator.Translate(Expression node)
   at Microsoft.EntityFrameworkCore.Query.Internal.LinqToCSharpSyntaxTranslator.VisitBlock(BlockExpression block)
   at Microsoft.EntityFrameworkCore.Query.Internal.LinqToCSharpSyntaxTranslator.Visit(Expression node)
   at Microsoft.EntityFrameworkCore.Query.Internal.LinqToCSharpSyntaxTranslator.VisitLoop(LoopExpression loop)
   at Microsoft.EntityFrameworkCore.Query.Internal.LinqToCSharpSyntaxTranslator.Visit(Expression node)
   at Microsoft.EntityFrameworkCore.Query.Internal.LinqToCSharpSyntaxTranslator.Translate(Expression node)
   at Microsoft.EntityFrameworkCore.Query.Internal.LinqToCSharpSyntaxTranslator.VisitBlock(BlockExpression block)
   at Microsoft.EntityFrameworkCore.Query.Internal.LinqToCSharpSyntaxTranslator.Visit(Expression node)
   at Microsoft.EntityFrameworkCore.Query.Internal.LinqToCSharpSyntaxTranslator.Translate(Expression node)
   at Microsoft.EntityFrameworkCore.Query.Internal.LinqToCSharpSyntaxTranslator.VisitBlock(BlockExpression block)
   at Microsoft.EntityFrameworkCore.Query.Internal.LinqToCSharpSyntaxTranslator.Visit(Expression node)
   at Microsoft.EntityFrameworkCore.Query.Internal.LinqToCSharpSyntaxTranslator.Translate(Expression node)
   at Microsoft.EntityFrameworkCore.Query.Internal.LinqToCSharpSyntaxTranslator.TranslateConditional(ConditionalExpression conditional, IdentifierNameSyntax lowerableAssignmentVariable)
   at Microsoft.EntityFrameworkCore.Query.Internal.LinqToCSharpSyntaxTranslator.VisitConditional(ConditionalExpression conditional)
   at Microsoft.EntityFrameworkCore.Query.Internal.LinqToCSharpSyntaxTranslator.Visit(Expression node)
   at Microsoft.EntityFrameworkCore.Query.Internal.LinqToCSharpSyntaxTranslator.Translate(Expression node)
   at Microsoft.EntityFrameworkCore.Query.Internal.LinqToCSharpSyntaxTranslator.VisitLambda[T](Expression`1 lambda)
   at Microsoft.EntityFrameworkCore.Query.Internal.LinqToCSharpSyntaxTranslator.Visit(Expression node)
   at Microsoft.EntityFrameworkCore.Query.Internal.LinqToCSharpSyntaxTranslator.TranslateCore(Expression node, ISet`1 collectedNamespaces, Boolean statementContext)
   at Microsoft.EntityFrameworkCore.Query.Internal.LinqToCSharpSyntaxTranslator.TranslateExpression(Expression node, ISet`1 collectedNamespaces)
   at Microsoft.EntityFrameworkCore.Design.Internal.CSharpHelper.Expression(Expression node, ISet`1 collectedNamespaces)
   at Microsoft.EntityFrameworkCore.Design.Internal.CSharpRuntimeAnnotationCodeGenerator.Create(ValueConverter converter, CSharpRuntimeAnnotationCodeGeneratorParameters parameters, ICSharpHelper codeHelper)
   at Microsoft.EntityFrameworkCore.Design.Internal.RelationalCSharpRuntimeAnnotationCodeGenerator.Create(CoreTypeMapping typeMapping, CSharpRuntimeAnnotationCodeGeneratorParameters parameters, ValueComparer valueComparer, ValueComparer keyValueComparer, ValueComparer providerValueComparer)
   at Npgsql.EntityFrameworkCore.PostgreSQL.Design.Internal.NpgsqlCSharpRuntimeAnnotationCodeGenerator.Create(CoreTypeMapping typeMapping, CSharpRuntimeAnnotationCodeGeneratorParameters parameters, ValueComparer valueComparer, ValueComparer keyValueComparer, ValueComparer providerValueComparer)
   at Microsoft.EntityFrameworkCore.Design.Internal.ICSharpRuntimeAnnotationCodeGenerator.Create(CoreTypeMapping typeMapping, IProperty property, CSharpRuntimeAnnotationCodeGeneratorParameters parameters)
   at Microsoft.EntityFrameworkCore.Scaffolding.Internal.CSharpRuntimeModelCodeGenerator.Create(IProperty property, String variableName, Dictionary`2 propertyVariables, CSharpRuntimeAnnotationCodeGeneratorParameters parameters)
   at Microsoft.EntityFrameworkCore.Scaffolding.Internal.CSharpRuntimeModelCodeGenerator.Create(IProperty property, Dictionary`2 propertyVariables, CSharpRuntimeAnnotationCodeGeneratorParameters parameters)
   at Microsoft.EntityFrameworkCore.Scaffolding.Internal.CSharpRuntimeModelCodeGenerator.CreateEntityType(IEntityType entityType, IndentedStringBuilder mainBuilder, IndentedStringBuilder methodBuilder, SortedSet`1 namespaces, String className, Boolean nullable)
   at Microsoft.EntityFrameworkCore.Scaffolding.Internal.CSharpRuntimeModelCodeGenerator.GenerateEntityType(IEntityType entityType, String namespace, String className, Boolean nullable)
   at Microsoft.EntityFrameworkCore.Scaffolding.Internal.CSharpRuntimeModelCodeGenerator.GenerateModel(IModel model, CompiledModelCodeGenerationOptions options)
   at Microsoft.EntityFrameworkCore.Scaffolding.Internal.CompiledModelScaffolder.ScaffoldModel(IModel model, String outputDir, CompiledModelCodeGenerationOptions options)
   at Microsoft.EntityFrameworkCore.Design.Internal.DbContextOperations.Optimize(String outputDir, String modelNamespace, String contextTypeName)
   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.OptimizeContextImpl(String outputDir, String modelNamespace, String contextType)
   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.OptimizeContext.<>c__DisplayClass0_0.<.ctor>b__0()
   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.OperationBase.Execute(Action action)

Include provider and version information

EF Core version: 8.0.0
Database provider: Npgsql.EntityFrameworkCore.PostgreSQL
Target framework: .NET 8.0
Operating system: Linux Debian Testing
IDE: JetBrains Rider 2023.3.2

Originally reported in npgsql/efcore.pg#2976

[XieJJ99]

We're facing the same issue, the model works without pre-compiled model, but throws the "System.ArgumentOutOfRangeException: Specified argument was out of the range of valid values." exception when trying to generate the optimized model.
We attempted the following solutions without success:

Marking the property as PrimitiveCollection
Marking the property as PrimitiveCollection and then set the element conversion to int

[ajcvickers]

Note for triage: this is a regression on the Npgsql provider from 7 to 8. Does not repro with SQL Server. /cc @roji

[roji]

This indeed turned out to be incorrect handling of compound assignment operators in LinqToCSharpSyntaxTranslator (anything like +=, *=). Submitted #32715 to fix that.

Once that's fixed, the translator still fails on another error. The incoming LINQ tree is as follows:

value => value == null ? null :
{
    int[] result;
    int length;
    int i;
    length = value.Count;
    result = new int[length];
    {
        i = 0;
        Loop(Break: LoopBreak Continue: )
        {
            i < length ?
            {
                result[i] = Invoke(value => (int)value, value[i]);
                return (i += 1)
                ;
            } : Goto(break LoopBreak)
        }
    }
    return result;
}

This code is from NpgsqlArrayConverter; this is a composing value converter that knows how to convert between arrays given an element value converter (this is why this issue is PG-only).

It's not really visible in the code above, but the expression produces by the converter has two nested blocks, each declaring the variable i, effectively as follows:

var i = 0;
{
    var i = 8;
}

Although this works in LINQ, this is of course illegal in C# and causes LinqToCSharpSyntaxTranslator to bomb (the error message should be improved, #32716). Once the unneeded outer declaration is removed (npgsql/efcore.pg#3047), the compiled model is generated successfully.

[roji]

While after these fixes the compiled model can be generated, it is invalid since NpgsqlArrayConverter produces statement/loop nodes, but these are invalid in the Expression<Func<...>> context where the tree is required. Opened #32717 to track/discuss.

Accordingly, am removing servicing-consider from this... In any case, the compound assignment problem tracked by this issue is trivial to work around in Npgsql code, so we don't really need to patch it.