Rename to v_cosine, add analyzer tests for implicit casting

Author: carlosdelest

x-pack/plugin/esql/src/internalClusterTest/java/org/elasticsearch/xpack/esql/vector/VectorSimilarityFunctionsIT.java

@@ -35,7 +35,7 @@ public class VectorSimilarityFunctionsIT extends AbstractEsqlIntegTestCase {
     public static Iterable<Object[]> parameters() throws Exception {
         List<Object[]> params = new ArrayList<>();
 
-        params.add(new Object[] { "v_cosine_similarity", VectorSimilarityFunction.COSINE });
+        params.add(new Object[] { "v_cosine", VectorSimilarityFunction.COSINE });
 
         return params;
     }

x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/expression/function/EsqlFunctionRegistry.java

@@ -489,7 +489,7 @@ private static FunctionDefinition[][] snapshotFunctions() {
                 def(StGeohex.class, StGeohex::new, "st_geohex"),
                 def(StGeohexToLong.class, StGeohexToLong::new, "st_geohex_to_long"),
                 def(StGeohexToString.class, StGeohexToString::new, "st_geohex_to_string"),
-                def(CosineSimilarity.class, CosineSimilarity::new, "v_cosine_similarity") } };
+                def(CosineSimilarity.class, CosineSimilarity::new, "v_cosine") } };
     }
 
     public EsqlFunctionRegistry snapshotRegistry() {

x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/expression/function/vector/VectorSimilarityFunction.java

@@ -32,7 +32,7 @@
 /**
  * Base class for vector similarity functions, which compute a similarity score between two dense vectors
  */
-abstract class VectorSimilarityFunction extends EsqlScalarFunction implements VectorFunction {
+public abstract class VectorSimilarityFunction extends EsqlScalarFunction implements VectorFunction {
 
     private final Expression left;
     private final Expression right;

x-pack/plugin/esql/src/test/java/org/elasticsearch/xpack/esql/analysis/AnalyzerTests.java

@@ -57,6 +57,7 @@
 import org.elasticsearch.xpack.esql.expression.function.scalar.string.Concat;
 import org.elasticsearch.xpack.esql.expression.function.scalar.string.Substring;
 import org.elasticsearch.xpack.esql.expression.function.vector.Knn;
+import org.elasticsearch.xpack.esql.expression.function.vector.VectorSimilarityFunction;
 import org.elasticsearch.xpack.esql.expression.predicate.operator.arithmetic.Add;
 import org.elasticsearch.xpack.esql.expression.predicate.operator.comparison.Equals;
 import org.elasticsearch.xpack.esql.expression.predicate.operator.comparison.GreaterThan;
@@ -92,6 +93,7 @@
 import java.time.Period;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Locale;
 import java.util.Map;
 import java.util.Set;
 import java.util.function.Function;
@@ -123,6 +125,7 @@
 import static org.elasticsearch.xpack.esql.core.type.DataType.DATETIME;
 import static org.elasticsearch.xpack.esql.core.type.DataType.DATE_NANOS;
 import static org.elasticsearch.xpack.esql.core.type.DataType.DATE_PERIOD;
+import static org.elasticsearch.xpack.esql.core.type.DataType.DENSE_VECTOR;
 import static org.elasticsearch.xpack.esql.core.type.DataType.DOUBLE;
 import static org.elasticsearch.xpack.esql.core.type.DataType.LONG;
 import static org.elasticsearch.xpack.esql.core.type.DataType.UNSUPPORTED;
@@ -2370,7 +2373,7 @@ public void testImplicitCasting() {
         assertThat(e.getMessage(), containsString("[+] has arguments with incompatible types [datetime] and [datetime]"));
     }
 
-    public void testDenseVectorImplicitCasting() {
+    public void testDenseVectorImplicitCastingKnn() {
         assumeTrue("dense_vector capability not available", EsqlCapabilities.Cap.DENSE_VECTOR_FIELD_TYPE.isEnabled());
         Analyzer analyzer = analyzer(loadMapping("mapping-dense_vector.json", "vectors"));
 
@@ -2387,6 +2390,29 @@ public void testDenseVectorImplicitCasting() {
         assertThat(queryVector.value(), equalTo(List.of(0.342, 0.164, 0.234)));
     }
 
+    public void testDenseVectorImplicitCastingSimilarityFunctions() {
+        if (EsqlCapabilities.Cap.COSINE_VECTOR_SIMILARITY_FUNCTION.isEnabled()) {
+            checkDenseVectorImplicitCastingSimilarityFunction("v_cosine(vector, [0.342, 0.164, 0.234])");
+        }
+    }
+
+    private void checkDenseVectorImplicitCastingSimilarityFunction(String similarityFunction) {
+        var plan = analyze(String.format(Locale.ROOT, """
+            from test | eval similarity = %s
+            """, similarityFunction), "mapping-dense_vector.json");
+
+        var limit = as(plan, Limit.class);
+        var eval = as(limit.child(), Eval.class);
+        var alias = as(eval.fields().get(0), Alias.class);
+        assertEquals("similarity", alias.name());
+        var similarity = as(alias.child(), VectorSimilarityFunction.class);
+        var left = as(similarity.left(), FieldAttribute.class);
+        assertEquals("vector", left.name());
+        var right = as(similarity.right(), Literal.class);
+        assertThat(right.dataType(), is(DENSE_VECTOR));
+        assertThat(right.value(), equalTo(List.of(0.342, 0.164, 0.234)));;
+    }
+
     public void testRateRequiresCounterTypes() {
         assumeTrue("rate requires snapshot builds", Build.current().isSnapshot());
         Analyzer analyzer = analyzer(tsdbIndexResolution());

x-pack/plugin/esql/src/test/java/org/elasticsearch/xpack/esql/analysis/VerifierTests.java

@@ -2238,8 +2238,8 @@ private void checkFullTextFunctionsInStats(String functionInvocation) {
 
     public void testVectorSimilarityFunctionsNullArgs() throws Exception {
         if (EsqlCapabilities.Cap.COSINE_VECTOR_SIMILARITY_FUNCTION.isEnabled()) {
-            checkVectorSimilarityFunctionsNullArgs("v_cosine_similarity(null, vector)", "first");
-            checkVectorSimilarityFunctionsNullArgs("v_cosine_similarity(vector, null)", "second");
+            checkVectorSimilarityFunctionsNullArgs("v_cosine(null, vector)", "first");
+            checkVectorSimilarityFunctionsNullArgs("v_cosine(vector, null)", "second");
         }
     }