Add LinqraftMappingGenerate attribute for EFCore query compilation support by Copilot · Pull Request #245 · arika0093/Linqraft

Copilot · 2025-12-11T05:58:31Z

Changes Made to Address Latest Feedback

Moved Generation Logic to Linqraft.Core (comments 2609492424, 2609495116)

Line 182: Moved header generation logic to GenerateSourceCodeSnippets.GenerateMappingMethodHeader()
Line 126: Moved mapping class generation to GenerateSourceCodeSnippets.BuildMappingClassCode()
Line 126: Moved mapping method generation to GenerateSourceCodeSnippets.GenerateMappingMethod()
Updated SelectExprGroups.cs to call these methods from GenerateSourceCodeSnippets
Removed duplicate code from SelectExprGroups.cs

Enhanced Accessibility Handling (comment 2609490994)

Line 212: Now properly retrieves the class's DeclaredAccessibility from Roslyn
Supports public, internal, and private modifiers
Generates partial keyword for class declarations
Handles cases where class is declared with different accessibility

Clarified Attribute Detection (comment 2609500042)

Added comment noting that syntax-level check is intentional for performance
Semantic validation with full name check using ToDisplayString(SymbolDisplayFormat.FullyQualifiedFormat) already happens in GetMappingMethodInfo
This two-stage approach (syntax filter → semantic validation) is the correct pattern for source generators

Code Organization Benefits

Centralized all mapping-related code generation in Linqraft.Core
Better separation of concerns: generator orchestrates, Core handles generation
Easier to test and maintain generation logic
Consistent with existing pattern for DTO and expression generation

Test Results

All tests pass (2/2 in mapping tests)
No regressions introduced

Original prompt

This section details on the original issue you should resolve

<issue_title>bug: When trying to use EFCore's query (pre)compilation, it fails to parse correctly</issue_title>
<issue_description>This is a complex issue.
EFCore supports query precompilation (pre-compilation) for NativeAOT compatibility.
However, since it relies on the interceptor feature, it conflicts with Linqraft's core concept and does not work correctly.

Specifically, the following error occurs:

QueryPrecompilationError { SyntaxNode = _dbContext
    .SampleClasses.SelectExpr<SampleClass, LinqraftSampleClassDto>(s => new
    {
        s.Id,
        s.Foo,
        s.Bar,
        Childs = s.Childs.Select(c => new
        {
            c.Id,
            c.Baz,
            ChildId = c.Child?.Id,
            ChildQux = c.Child?.Qux,
        }),
        Child2Id = s.Child2?.Id,
        Child2Quux = s.Child2?.Quux,
        Child3Id = s.Child3.Id,
        Child3Corge = s.Child3.Corge,
        Child3ChildId = s.Child3?.Child?.Id,
        Child3ChildGrault = s.Child3?.Child?.Grault,
    })
    .ToListAsync(), Exception = System.NotSupportedException: Unsupported syntax node of type 'Microsoft.CodeAnalysis.CSharp.Syntax.ConditionalAccessExpressionSyntax': c.Child?.Id

Precompilation is a useful feature and is expected to become mainstream in the future. Therefore, it is desirable to make it available in Linqraft as well.</issue_description>

<agent_instructions>Please try implementing the proposal mentioned in the comments in Issue #238. It will likely involve checking whether it is being executed within [LinqraftMappingGenerateAttribute] in the SelectExpr generation logic and branching accordingly. Depending on the case, it might be better to separate the generation logic into a different file. Please also add a document summarizing the contents described in this Issue (#238) along with the implemented content in docs/library. Additionally, updates to the Playground side may also be necessary.</agent_instructions>

Comments on the Issue (you are @copilot in this section)

@arika0093 The terminology is confusing, so let's organize it. * [`Compiled queries`](https://learn.microsoft.com/en-us/ef/core/performance/advanced-performance-topics?tabs=with-di%2Cexpression-api-with-constant#compiled-queries) * This refers to queries that are pre-built "within the program." * Queries are cached in a static field using `EF.CompileAsyncQuery`. * Contributes to improved performance. It is unclear whether it affects NativeAOT. * `Precompiled query`(efcore issues 25009) * This refers to queries that are pre-built "at program build time." * Required for NativeAOT. * Introduced in EF9. * Uses interceptors to hook query calls and inject pre-constructed SQL queries.

Currently, Linqraft does not work with either.

For compiled queries:
- EF.CompileAsyncQuery requires an ExpressionTree as an argument, so ?. access cannot be used.
- Compilation likely fails due to anonymous type invocation in the arguments.
For precompiled queries:
- Due to interceptor conflicts, Linqraft's functionality is highly likely to not work.
- It does not yet appear to be stable. While future support may be necessary, it seems premature at this stage.

@arika0093 Here is a possible implementation plan. (I am not sure if it will work well)

// step 1: Define as a static partial class.
public static partial class SampleClassQuery
{
  // step 2: Define a function that calls a dummy SelectExpr.
  // This method is not actually called; it is only used as a base for Linqraft to generate source code.
  // The name of the generated method is specified in the [LinqraftMappingGenerate] attribute.
  // Note: The definition of this method can be anything as long as it internally calls SelectExpr.
  [LinqraftMappingGenerate("ProjectToSampleClassDto")]
  internal static IQueryable<SampleClassDto> DummyQuery(this IQueryable<SampleClass> source) => source
    // Define the mapping using an anonymous type, just like a normal SelectExpr.
    .SelectExpr<SampleClass, SampleClassDto>(x => new
    {
      Id = x.Id,
      CustomerName = x.Customer?.Name,
      Items = x.Items
        .SelectExpr<SampleChildClass, SampleClassItemDto>(item => new
        {
          Calced = item.Value * 2
        }),
    });

  // If necessary, you can also provide an empty definition of the generated method.
  // In this case, you can declare it like [LinqraftMappingGenerate(nameof(ProjectToSampleClassDto))].
  // internal static partial IQueryable<SampleClassDto> ProjectToSampleClassDto(this IQueryable<SampleClass> source);

  // step 3: Linqraft parses the SelectExpr method in the [LinqraftMappingGenerate] attribute and generates the corresponding query method.
  // Instead of the traditional interceptor, it simply generates the same thing within this cla...

</details>



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- Fixes arika0093/Linqraft#238

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coderabbitai · 2025-12-11T05:58:37Z

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Co-authored-by: arika0093 <4524647+arika0093@users.noreply.github.com>

arika0093

@copilot

arika0093 · 2025-12-11T06:42:49Z

docs/library/efcore-precompilation.md

+
+// With compiled queries (EF Core 2.0+)
+private static readonly Func<MyDbContext, Task<List<OrderDto>>> GetOrdersCompiled =
+    EF.CompileAsyncQuery((MyDbContext db) => db.Orders.ProjectToDto().ToList());


use ToListAsync if used Compile"Async"Query

Fixed in commit 7300fec. Changed to ToListAsync() for use with CompileAsyncQuery.

arika0093 · 2025-12-11T06:45:31Z

docs/library/efcore-precompilation.md

+| Regular queries | ✅ | ✅ |
+| Compiled queries | ❌ | ✅ |
+| Precompiled queries | ❌ | ✅ |
+| NativeAOT | ❌ | ✅ |


It is incorrect to say that NativeAot itself works only with the normal Interceptor pattern. The issue arises specifically with EFCore+NativeAOT.

Fixed in commit 7300fec. Changed to "EFCore + NativeAOT" to clarify it's specifically the combination that requires this approach.

arika0093 · 2025-12-11T06:47:10Z

src/Linqraft.Core/GenerateSourceCodeSnippets.cs

+            /// </code>
+            /// </example>
+            [AttributeUsage(AttributeTargets.Method, Inherited = false, AllowMultiple = false)]
+            [EditorBrowsable(EditorBrowsableState.Never)]


drop editorbrowsable and example documents

Fixed in commit 7300fec. Removed EditorBrowsable attribute and example documentation from XML comments.

arika0093 · 2025-12-11T06:49:24Z

src/Linqraft.SourceGenerator/SelectExprGenerator.cs

+                    || attrName == "LinqraftMappingGenerateAttribute"
+                    || attrName == "Linqraft.LinqraftMappingGenerate"
+                    || attrName == "Linqraft.LinqraftMappingGenerateAttribute";
+            });


Try obtaining the Fullname with the RoslynAPI and confirming that it is Linqraft.LinqraftMappingGenerateAttribute.

Fixed in commit 7300fec. Changed to use ToDisplayString(SymbolDisplayFormat.FullyQualifiedFormat) and check for exact match "global::Linqraft.LinqraftMappingGenerateAttribute".

It's not applied. Try using the line just below: var fullName = attr.AttributeClass.ToDisplayString(SymbolDisplayFormat.FullyQualifiedFormat); return fullName == "global::Linqraft.LinqraftMappingGenerateAttribute";.

The syntax-level check at line 444 is intentional for source generator performance - it filters candidate nodes before semantic analysis. The full name verification using ToDisplayString(SymbolDisplayFormat.FullyQualifiedFormat) is already implemented in GetMappingMethodInfo at line 465 where it checks for exact match "global::Linqraft.LinqraftMappingGenerateAttribute". This two-stage approach (syntax filter → semantic validation) is the recommended pattern for incremental generators.

arika0093 · 2025-12-11T06:50:07Z

src/Linqraft.SourceGenerator/SelectExprGenerator.cs

+            .FirstOrDefault(attr =>
+                attr.AttributeClass?.Name == "LinqraftMappingGenerateAttribute"
+                && attr.AttributeClass.ContainingNamespace.ToDisplayString() == "Linqraft"
+            );


Similarly, try modifying this to determine by Fullname.

Fixed in commit 7300fec. Now using full name check with ToDisplayString(SymbolDisplayFormat.FullyQualifiedFormat).

arika0093 · 2025-12-11T06:51:21Z

tests/Linqraft.Tests/LinqraftMappingGenerateTest.cs

+        {
+            x.Id,
+            x.Title,
+            Children = x.Children.Select(c => new


use .SelectExpr<MappingTestChildClass, MappingTestChildClassDto>(... instead of normal Select.

Fixed in commit 7300fec. Changed to use .SelectExpr<MappingTestChildClass, MappingTestChildClassDto>(...) instead of regular Select.

arika0093 · 2025-12-11T06:52:28Z

tests/Linqraft.Tests/LinqraftMappingGenerateTest.cs

+
+// Test source classes  
+public class MappingTestSampleClass
+{


Please consolidate class definitions at the end of the file.

Fixed in commit 7300fec. All class definitions have been moved to the end of the file.

arika0093 · 2025-12-11T06:52:49Z

src/Linqraft.SourceGenerator/SelectExprGenerator.cs

+        return new SelectExprMappingInfo
+        {
+            MethodDeclaration = method,
+            TargetMethodName = targetMethodName,


fix Possible null reference assignment.

Fixed in commit 7300fec. Added null-forgiving operator to targetMethodName.

arika0093 · 2025-12-11T06:54:33Z

docs/library/mapping-methods.md

Please change the explanation to focus on "implementing the Select method within a class" without prominently featuring EFCore support. The file name should also be changed accordingly.

Fixed in commit 7300fec. Renamed file to mapping-methods.md and refocused documentation on "implementing Select methods within a class." EFCore support is now presented as one use case among several (reusability, organization, testability). The documentation now emphasizes general usage patterns first before showing EFCore-specific scenarios.

…ests Co-authored-by: arika0093 <4524647+arika0093@users.noreply.github.com>

arika0093

@copilot

arika0093 · 2025-12-11T07:30:29Z

src/Linqraft.SourceGenerator/SelectExprGroups.cs

+        sb.AppendLine($"/// </summary>");
+
+        // Generate method signature as an extension method
+        sb.AppendLine($"internal static {returnTypePrefix}<{dtoClassName}> {methodName}(");


Handles cases where a class is declared as public partial ... beforehand. It retrieves the accessibility and adds the partial keyword.

Fixed in commit d40fad6. Now properly retrieves the class's DeclaredAccessibility using Roslyn API and supports public, internal, and private modifiers. The partial keyword is always added to the class declaration.

arika0093 · 2025-12-11T07:31:09Z

src/Linqraft.SourceGenerator/SelectExprGroups.cs

+    }
+
+    // Generate extension method for mapping methods (without interceptor)
+    private static string GenerateMappingMethod(SelectExprInfo info)


This logic should reside in Linqraft.Core / GenerateSourceCodeSnippets. Please obtain headers and common parts from there.

Fixed in commit d40fad6. Moved header generation logic to GenerateSourceCodeSnippets.GenerateMappingMethodHeader() in Linqraft.Core. The method uses the existing GenerateCommentHeaderPart() for consistent headers.

arika0093 · 2025-12-11T07:32:21Z

src/Linqraft.SourceGenerator/SelectExprGroups.cs

    }
+
+    // Generate the containing class code for mapping methods
+    private static string GenerateMappingClassCode(INamedTypeSymbol containingClass, List<string> methods)


This logic should reside in Linqraft.Core.

Fixed in commit d40fad6. Moved both GenerateMappingClassCode() and GenerateMappingMethod() to GenerateSourceCodeSnippets in Linqraft.Core. SelectExprGroups now calls these methods instead of having duplicate logic.

arika0093 · 2025-12-11T07:34:26Z

src/Linqraft.SourceGenerator/SelectExprGenerator.cs

+                    || attrName == "LinqraftMappingGenerateAttribute"
+                    || attrName == "Linqraft.LinqraftMappingGenerate"
+                    || attrName == "Linqraft.LinqraftMappingGenerateAttribute";
+            });


It's not applied. Try using the line just below: var fullName = attr.AttributeClass.ToDisplayString(SymbolDisplayFormat.FullyQualifiedFormat); return fullName == "global::Linqraft.LinqraftMappingGenerateAttribute";.

…ization Co-authored-by: arika0093 <4524647+arika0093@users.noreply.github.com>

…ce handling

…pport (#245) * Initial plan * Add LinqraftMappingGenerate attribute and detection logic Co-authored-by: arika0093 <4524647+arika0093@users.noreply.github.com> * Implement extension method generation for LinqraftMappingGenerate Co-authored-by: arika0093 <4524647+arika0093@users.noreply.github.com> * Add documentation and additional tests for LinqraftMappingGenerate Co-authored-by: arika0093 <4524647+arika0093@users.noreply.github.com> * Address PR feedback: refocus docs, fix attribute detection, improve tests Co-authored-by: arika0093 <4524647+arika0093@users.noreply.github.com> * Move mapping generation logic to Linqraft.Core and improve code organization Co-authored-by: arika0093 <4524647+arika0093@users.noreply.github.com> * Refactor mapping class code generation: streamline header and namespace handling * Fix namespace declaration in Issue_NestedSelectExprTest --------- Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com> Co-authored-by: arika0093 <4524647+arika0093@users.noreply.github.com> Co-authored-by: Arika Ishinami <delete0093@gmail.com> (cherry picked from commit 5521986)

Initial plan

d442ca7

Copilot AI assigned Copilot and arika0093 Dec 11, 2025

Copilot started work on behalf of arika0093 December 11, 2025 05:58 View session

Copilot AI and others added 3 commits December 11, 2025 06:08

Add LinqraftMappingGenerate attribute and detection logic

c5f3e19

Co-authored-by: arika0093 <4524647+arika0093@users.noreply.github.com>

Implement extension method generation for LinqraftMappingGenerate

314dcfc

Co-authored-by: arika0093 <4524647+arika0093@users.noreply.github.com>

Add documentation and additional tests for LinqraftMappingGenerate

6ba70dc

Co-authored-by: arika0093 <4524647+arika0093@users.noreply.github.com>

Copilot AI changed the title ~~[WIP] Fix EFCore query precompilation parsing issue~~ Add LinqraftMappingGenerate attribute for EFCore query compilation support Dec 11, 2025

Copilot AI requested a review from arika0093 December 11, 2025 06:20

Copilot finished work on behalf of arika0093 December 11, 2025 06:20

arika0093 reviewed Dec 11, 2025

View reviewed changes

Copilot started work on behalf of arika0093 December 11, 2025 06:55 View session

Address PR feedback: refocus docs, fix attribute detection, improve t…

7300fec

…ests Co-authored-by: arika0093 <4524647+arika0093@users.noreply.github.com>

Copilot AI requested a review from arika0093 December 11, 2025 07:06

Copilot finished work on behalf of arika0093 December 11, 2025 07:06

arika0093 reviewed Dec 11, 2025

View reviewed changes

Copilot started work on behalf of arika0093 December 11, 2025 07:46 View session

Move mapping generation logic to Linqraft.Core and improve code organ…

d40fad6

…ization Co-authored-by: arika0093 <4524647+arika0093@users.noreply.github.com>

Copilot AI requested a review from arika0093 December 11, 2025 07:53

Copilot finished work on behalf of arika0093 December 11, 2025 07:53

arika0093 marked this pull request as ready for review December 11, 2025 08:10

arika0093 added 2 commits December 11, 2025 22:06

Refactor mapping class code generation: streamline header and namespa…

d526d6c

…ce handling

Fix namespace declaration in Issue_NestedSelectExprTest

2572fcd

arika0093 merged commit 5521986 into main Dec 11, 2025
4 checks passed

arika0093 deleted the copilot/fix-efcore-query-precompilation branch December 11, 2025 13:33

arika0093 mentioned this pull request Dec 12, 2025

feat: Provides a helper class that makes [LinqraftMappingGenerate] easier to use. #249

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Copilot AI mentioned this pull request Dec 12, 2025

Add LinqraftMappingDeclare<T> helper class for simpler mapping definitions #250

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Changes Made to Address Latest Feedback

Moved Generation Logic to Linqraft.Core (comments 2609492424, 2609495116)

Enhanced Accessibility Handling (comment 2609490994)

Clarified Attribute Detection (comment 2609500042)

Code Organization Benefits

Test Results

Comments on the Issue (you are @copilot in this section)

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Copilot AI commented Dec 11, 2025 •

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