From 89e0d52a93c4eea088407e4d125ccbf9dcc6fb8d Mon Sep 17 00:00:00 2001
From: Shay Rojansky <roji@roji.org>
Date: Fri, 10 Jul 2026 10:22:09 +0200
Subject: [PATCH] Fix GIN index detection for views

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
---
 ...yableMethodTranslatingExpressionVisitor.cs | 12 +++++------
 ...aredPrimitiveCollectionsQueryNpgsqlTest.cs | 21 +++++++++++++++++++
 2 files changed, 27 insertions(+), 6 deletions(-)

diff --git a/src/EFCore.PG/Query/Internal/NpgsqlQueryableMethodTranslatingExpressionVisitor.cs b/src/EFCore.PG/Query/Internal/NpgsqlQueryableMethodTranslatingExpressionVisitor.cs
index a20f17e02f..f6f38ca53b 100644
--- a/src/EFCore.PG/Query/Internal/NpgsqlQueryableMethodTranslatingExpressionVisitor.cs
+++ b/src/EFCore.PG/Query/Internal/NpgsqlQueryableMethodTranslatingExpressionVisitor.cs
@@ -703,12 +703,12 @@ protected override ShapedQueryExpression TransformJsonQueryToTable(JsonQueryExpr
                 return array switch
                 {
                     // For array columns which have a GIN index, we translate to array containment (with @>) which uses that index.
-                    ColumnExpression { Column: IColumn column }
-                        when column.Table.Indexes
-                            .Any(i =>
-                                i.Columns.Count > 0
-                                && i.Columns[0] == column
-                                && i.MappedIndexes.Any(mi => mi.GetMethod()?.Equals("GIN", StringComparison.OrdinalIgnoreCase) == true))
+                    ColumnExpression { Column: IColumnBase column }
+                        when column.PropertyMappings.Any(
+                            m => m.Property.GetContainingIndexes().Any(
+                                i => i.Properties.Count > 0
+                                    && i.Properties[0] == m.Property
+                                    && i.GetMethod()?.Equals("GIN", StringComparison.OrdinalIgnoreCase) == true))
                         => BuildSimplifiedShapedQuery(
                             source,
                             _sqlExpressionFactory.Contains(
diff --git a/test/EFCore.PG.FunctionalTests/Query/NonSharedPrimitiveCollectionsQueryNpgsqlTest.cs b/test/EFCore.PG.FunctionalTests/Query/NonSharedPrimitiveCollectionsQueryNpgsqlTest.cs
index 5ea8bc4860..278c5cbf0c 100644
--- a/test/EFCore.PG.FunctionalTests/Query/NonSharedPrimitiveCollectionsQueryNpgsqlTest.cs
+++ b/test/EFCore.PG.FunctionalTests/Query/NonSharedPrimitiveCollectionsQueryNpgsqlTest.cs
@@ -135,6 +135,27 @@ LIMIT 2
 """);
     }
 
+    [ConditionalFact]
+    public virtual async Task View_column_collection_Contains_with_GIN_index_uses_containment()
+    {
+        var contextFactory = await InitializeAsync<TestContext>(
+            onModelCreating: mb => mb.Entity<TestEntity>()
+                .ToView("TestView")
+                .HasIndex(e => e.Ints)
+                .HasMethod("GIN"),
+            onConfiguring: b => b.ConfigureWarnings(w => w.Ignore(RelationalEventId.AllIndexPropertiesNotToMappedToAnyTable)));
+
+        await using var context = contextFactory.CreateContext();
+
+        Assert.Equal(
+            """
+SELECT t."Id", t."Ints"
+FROM "TestView" AS t
+WHERE t."Ints" @> ARRAY[4]::integer[]
+""",
+            context.Set<TestEntity>().Where(c => c.Ints!.Contains(4)).ToQueryString());
+    }
+
     [ConditionalFact]
     public virtual async Task Column_collection_Contains_with_btree_index_does_not_use_containment()
     {