feat: add BM25Operator.AndCross for cross-property keyword AND (Weaviate 1.38.8+)

.github/workflows/main.yaml

@@ -136,7 +136,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        version: ["1.32.27", "1.33.18", "1.34.20", "1.35.23", "1.36.21", "1.37.12", "1.38.4"]
+        version: ["1.32.27", "1.33.18", "1.34.20", "1.35.23", "1.36.23", "1.37.14", "1.38.9", "1.39.0"]
     uses: ./.github/workflows/test-on-weaviate-version.yml
     secrets: inherit
     with:

src/Weaviate.Client.Tests/Integration/TestQueries.cs

@@ -144,6 +144,84 @@ await collection.Data.InsertMany(
         Assert.Equal("apples are big", firstObject.BelongsToGroup);
     }
 
+    /// <summary>
+    /// Tests that test bm 25 operator and cross matches tokens across properties
+    /// </summary>
+    [Fact]
+    public async Task Test_BM25_Operator_AndCross()
+    {
+        RequireVersion("1.38.8");
+
+        var collection = await CollectionFactory(
+            properties: [Property.Text("title"), Property.Text("body")],
+            vectorConfig: Configure.Vector(t => t.SelfProvided())
+        );
+
+        // Neither of splitAcross's properties holds both tokens, so only cross-property AND matches it.
+        var splitAcross = await collection.Data.Insert(
+            new { title = "banana", body = "split" },
+            cancellationToken: TestContext.Current.CancellationToken
+        );
+        var singleProperty = await collection.Data.Insert(
+            new { title = "banana split", body = "dessert" },
+            cancellationToken: TestContext.Current.CancellationToken
+        );
+        await collection.Data.Insert(
+            new { title = "banana", body = "bread" },
+            cancellationToken: TestContext.Current.CancellationToken
+        );
+
+        var andObjs = await collection.Query.BM25(
+            "banana split",
+            searchOperator: new BM25Operator.And(),
+            cancellationToken: TestContext.Current.CancellationToken
+        );
+        Assert.Equal(new List<Guid?> { singleProperty }, andObjs.Select(o => o.UUID).ToList());
+
+        var andCrossObjs = await collection.Query.BM25(
+            "banana split",
+            searchOperator: new BM25Operator.AndCross(),
+            cancellationToken: TestContext.Current.CancellationToken
+        );
+        var expected = new List<Guid?> { splitAcross, singleProperty };
+        expected.Sort();
+        Assert.Equal(expected, andCrossObjs.Select(o => o.UUID).OrderBy(x => x).ToList());
+    }
+
+    /// <summary>
+    /// Tests that test bm 25 operator and cross rejects mixed tokenization
+    /// </summary>
+    [Fact]
+    public async Task Test_BM25_Operator_AndCross_MixedTokenization_Errors()
+    {
+        RequireVersion("1.38.8");
+
+        var collection = await CollectionFactory(
+            properties:
+            [
+                Property.Text("title", tokenization: PropertyTokenization.Word),
+                Property.Text("code", tokenization: PropertyTokenization.Field),
+            ],
+            vectorConfig: Configure.Vector(t => t.SelfProvided())
+        );
+
+        await collection.Data.Insert(
+            new { title = "banana split", code = "banana-split" },
+            cancellationToken: TestContext.Current.CancellationToken
+        );
+
+        var exception = await Assert.ThrowsAnyAsync<WeaviateException>(async () =>
+            await collection.Query.BM25(
+                "banana split",
+                searchFields: ["title", "code"],
+                searchOperator: new BM25Operator.AndCross(),
+                cancellationToken: TestContext.Current.CancellationToken
+            )
+        );
+        Assert.NotNull(exception.InnerException);
+        Assert.Contains("tokenization", exception.InnerException.Message);
+    }
+
     /// <summary>
     /// Tests that test collection generative fetch objects
     /// </summary>

src/Weaviate.Client.Tests/Integration/TestSearchHybrid.cs

@@ -831,6 +831,55 @@ await collection.Query.Hybrid(
         Assert.Equal(expected, rest);
     }
 
+    /// <summary>
+    /// Tests that test hybrid bm 25 operator and cross
+    /// </summary>
+    [Fact]
+    public async Task Test_Hybrid_BM25_Operator_AndCross()
+    {
+        RequireVersion("1.38.8");
+
+        var collection = await CollectionFactory(
+            properties: new[] { Property.Text("title"), Property.Text("body") },
+            vectorConfig: Configure.Vector(t => t.SelfProvided())
+        );
+
+        // Neither of splitAcross's properties holds both tokens, so only cross-property AND matches it.
+        var splitAcross = await collection.Data.Insert(
+            new { title = "banana", body = "split" },
+            vectors: new float[] { 1, 0, 0, 0 },
+            cancellationToken: TestContext.Current.CancellationToken
+        );
+        await collection.Data.Insert(
+            new { title = "banana", body = "bread" },
+            vectors: new float[] { 0, 1, 0, 0 },
+            cancellationToken: TestContext.Current.CancellationToken
+        );
+
+        var andObjs = (
+            await collection.Query.Hybrid(
+                "banana split",
+                vectors: null,
+                alpha: 0.0f,
+                bm25Operator: new BM25Operator.And(),
+                cancellationToken: TestContext.Current.CancellationToken
+            )
+        ).ToList();
+        Assert.Empty(andObjs);
+
+        var andCrossObjs = (
+            await collection.Query.Hybrid(
+                "banana split",
+                vectors: null,
+                alpha: 0.0f,
+                bm25Operator: new BM25Operator.AndCross(),
+                cancellationToken: TestContext.Current.CancellationToken
+            )
+        ).ToList();
+        Assert.Single(andCrossObjs);
+        Assert.Equal(splitAcross, andCrossObjs[0].UUID);
+    }
+
     /// <summary>
     /// Tests that test aggregate max vector distance
     /// </summary>

src/Weaviate.Client.Tests/Unit/Mocks/MockHelpers.cs

@@ -217,6 +217,7 @@ public static (
         {
             grpcClient.SetUseAlphaParam(true);
         }
+        grpcClient.SetServerVersion(weaviateVersion);
 
         var client = new WeaviateClient(grpcClient: grpcClient, meta: meta);