Add AsExpandedProperties IQueryable extension method

src/EntityFrameworkCore.Projectables/Extensions/QueryableExtensions.cs

@@ -7,4 +7,29 @@ public static class QueryableExtensions
     /// </summary>
     public static IQueryable<TModel> ExpandProjectables<TModel>(this IQueryable<TModel> query)
         => query.Provider.CreateQuery<TModel>(query.Expression.ExpandProjectables());
+
+    /// <summary>
+    /// Ensures that all writable <c>[Projectable]</c> properties on <typeparamref name="TModel"/> are populated
+    /// in query results by automatically generating a SELECT projection that merges all EF-mapped properties and navigations with
+    /// the expression-expanded value of every writable projectable property.
+    /// <para>
+    /// This method is particularly useful when fetching full entities (e.g. <c>FirstAsync()</c>,
+    /// <c>ToListAsync()</c>) on queries that are tracked by default, where the automatic select injection is
+    /// otherwise suppressed to preserve change-tracking semantics. Call this method after any <c>Where</c>
+    /// or <c>OrderBy</c> clauses and before terminal operators.
+    /// </para>
+    /// <para>
+    /// This method currently delegates to <see cref="ExpandProjectables{TModel}(IQueryable{TModel})"/> and does
+    /// not override the root-rewrite guard for queries that already contain an explicit <c>AsTracking()</c> call
+    /// in the expression tree. As a result, <c>query.AsTracking().AsExpandedProperties()</c> does not currently
+    /// force projection injection.
+    /// </para>
+    /// <para>
+    /// Read-only projectable properties (those without a setter) are not included in the generated projection
+    /// because EF Core's materializer cannot set them on the resulting entity.
+    /// </para>
+    /// </summary>
+    public static IQueryable<TModel> AsExpandedProperties<TModel>(this IQueryable<TModel> query)
+        where TModel : class
+        => query.ExpandProjectables();
 }

tests/EntityFrameworkCore.Projectables.FunctionalTests/AsExpandedPropertiesTests.NoTrackingContext_QueryRoot_InjectsProjectableProperties.DotNet10_0.verified.txt

@@ -0,0 +1,2 @@
+SELECT [e].[Id], [e].[Id] * 3
+FROM [Entity] AS [e]

tests/EntityFrameworkCore.Projectables.FunctionalTests/AsExpandedPropertiesTests.NoTrackingContext_QueryRoot_InjectsProjectableProperties.DotNet8_0.verified.txt

@@ -0,0 +1,2 @@
+SELECT [e].[Id], [e].[Id] * 3
+FROM [Entity] AS [e]

tests/EntityFrameworkCore.Projectables.FunctionalTests/AsExpandedPropertiesTests.NoTrackingContext_QueryRoot_InjectsProjectableProperties.DotNet9_0.verified.txt

@@ -0,0 +1,2 @@
+SELECT [e].[Id], [e].[Id] * 3
+FROM [Entity] AS [e]

tests/EntityFrameworkCore.Projectables.FunctionalTests/AsExpandedPropertiesTests.TrackingContext_QueryRoot_InjectsWritableProjectableProperties.DotNet10_0.verified.txt

@@ -0,0 +1,2 @@
+SELECT [e].[Id], [e].[Id] * 3
+FROM [Entity] AS [e]

tests/EntityFrameworkCore.Projectables.FunctionalTests/AsExpandedPropertiesTests.TrackingContext_QueryRoot_InjectsWritableProjectableProperties.DotNet8_0.verified.txt

@@ -0,0 +1,2 @@
+SELECT [e].[Id], [e].[Id] * 3
+FROM [Entity] AS [e]

tests/EntityFrameworkCore.Projectables.FunctionalTests/AsExpandedPropertiesTests.TrackingContext_QueryRoot_InjectsWritableProjectableProperties.DotNet9_0.verified.txt

@@ -0,0 +1,2 @@
+SELECT [e].[Id], [e].[Id] * 3
+FROM [Entity] AS [e]

tests/EntityFrameworkCore.Projectables.FunctionalTests/AsExpandedPropertiesTests.TrackingContext_WithWhere_InjectsProjectablePropertiesAfterFilter.DotNet10_0.verified.txt

@@ -0,0 +1,3 @@
+SELECT [e].[Id], [e].[Id] * 3
+FROM [Entity] AS [e]
+WHERE [e].[Id] > 0

tests/EntityFrameworkCore.Projectables.FunctionalTests/AsExpandedPropertiesTests.TrackingContext_WithWhere_InjectsProjectablePropertiesAfterFilter.DotNet8_0.verified.txt

@@ -0,0 +1,3 @@
+SELECT [e].[Id], [e].[Id] * 3
+FROM [Entity] AS [e]
+WHERE [e].[Id] > 0

tests/EntityFrameworkCore.Projectables.FunctionalTests/AsExpandedPropertiesTests.TrackingContext_WithWhere_InjectsProjectablePropertiesAfterFilter.DotNet9_0.verified.txt

@@ -0,0 +1,3 @@
+SELECT [e].[Id], [e].[Id] * 3
+FROM [Entity] AS [e]
+WHERE [e].[Id] > 0

tests/EntityFrameworkCore.Projectables.FunctionalTests/AsExpandedPropertiesTests.cs

@@ -0,0 +1,71 @@
+using EntityFrameworkCore.Projectables.Extensions;
+using EntityFrameworkCore.Projectables.FunctionalTests.Helpers;
+using Microsoft.EntityFrameworkCore;
+
+namespace EntityFrameworkCore.Projectables.FunctionalTests;
+
+public class AsExpandedPropertiesTests
+{
+    /// <summary>
+    /// Entity with both a read-only and a writable projectable property.
+    /// <list type="bullet">
+    ///   <item><c>ReadOnlyComputed</c> — expression-bodied (no setter); excluded from auto-inject.</item>
+    ///   <item><c>WritableComputed</c> — has a setter; included in auto-inject.</item>
+    /// </list>
+    /// </summary>
+    public class Entity
+    {
+        public int Id { get; set; }
+
+        /// <summary>Read-only projectable: NOT included in the auto-generated SELECT (no setter).</summary>
+        [Projectable]
+        public int ReadOnlyComputed => Id * 2;
+
+        /// <summary>Writable projectable: IS included in the auto-generated SELECT (has setter).</summary>
+        [Projectable]
+        public int WritableComputed
+        {
+            get => Id * 3;
+            set { }
+        }
+    }
+
+    [Fact]
+    public Task TrackingContext_QueryRoot_InjectsWritableProjectableProperties()
+    {
+        // Tracking context: without AsExpandedProperties() the auto-inject is suppressed.
+        // AsExpandedProperties() forces the Select injection regardless of tracking mode.
+        // ReadOnlyComputed is absent from SELECT (no setter); WritableComputed is present.
+        using var dbContext = new SampleDbContext<Entity>(queryTrackingBehavior: QueryTrackingBehavior.TrackAll);
+
+        var query = dbContext.Set<Entity>().AsExpandedProperties();
+
+        return Verifier.Verify(query.ToQueryString());
+    }
+
+    [Fact]
+    public Task TrackingContext_WithWhere_InjectsProjectablePropertiesAfterFilter()
+    {
+        // Verifies that AsExpandedProperties() wraps the Where clause (not the raw root),
+        // so the generated SQL contains WHERE and SELECT in the correct order.
+        using var dbContext = new SampleDbContext<Entity>(queryTrackingBehavior: QueryTrackingBehavior.TrackAll);
+
+        var query = dbContext.Set<Entity>()
+            .Where(e => e.Id > 0)
+            .AsExpandedProperties();
+
+        return Verifier.Verify(query.ToQueryString());
+    }
+
+    [Fact]
+    public Task NoTrackingContext_QueryRoot_InjectsProjectableProperties()
+    {
+        // NoTracking context: auto-inject already happens automatically via UseProjectables();
+        // calling AsExpandedProperties() explicitly should produce the same result.
+        using var dbContext = new SampleDbContext<Entity>(queryTrackingBehavior: QueryTrackingBehavior.NoTracking);
+
+        var query = dbContext.Set<Entity>().AsExpandedProperties();
+
+        return Verifier.Verify(query.ToQueryString());
+    }
+}