ES|QL: Release decay function (#137830)

Author: ioanatia

docs/changelog/137830.yaml

@@ -0,0 +1,5 @@
+pr: 137830
+summary: Release decay function
+area: ES|QL
+type: feature
+issues: []

docs/reference/query-languages/esql/_snippets/functions/layout/decay.md

@@ -20,7 +20,7 @@ including [KNN](dense-vector-functions.md#esql-knn), please refer to
 the [Dense vector functions](dense-vector-functions.md) documentation.
 :::
 
-Use these functions for [full-text search](docs-content://solutions/search/full-text.md) 
+Use these functions for [full-text search](docs-content://solutions/search/full-text.md)
 and [semantic search](docs-content://solutions/search/semantic-search/semantic-search-semantic-text.md).
 
 Full text functions can be used to
@@ -56,14 +56,11 @@ for information on the limitations of full text search.
 :::{include} ../_snippets/functions/layout/score.md
 :::
 
+:::{include} ../_snippets/functions/layout/decay.md
+:::
+
 % TERM is currently a hidden feature
 % To make it visible again, uncomment this and the line in
 lists/search-functions.md
 % :::{include} ../_snippets/functions/layout/term.md
 % :::
-
-% DECAY is currently a hidden feature
-% To make it visible again, uncomment this and the line in
-lists/search-functions.md
-% :::{include} ../_snippets/functions/layout/decay.md
-% :::

docs/reference/query-languages/esql/functions-operators/search-functions.md

@@ -1351,7 +1351,7 @@ public enum Cap {
         /**
          * Decay function for custom scoring
          */
-        DECAY_FUNCTION(Build.current().isSnapshot()),
+        DECAY_FUNCTION,
 
         /**
          * FIRST and LAST aggregate functions.

x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/action/EsqlCapabilities.java

@@ -26,13 +26,11 @@ public static List<NamedWriteableRegistry.Entry> getNamedWriteables() {
         entries.add(Kql.ENTRY);
         entries.add(MatchPhrase.ENTRY);
         entries.add(Score.ENTRY);
+        entries.add(Decay.ENTRY);
 
         if (EsqlCapabilities.Cap.TERM_FUNCTION.isEnabled()) {
             entries.add(Term.ENTRY);
         }
-        if (EsqlCapabilities.Cap.DECAY_FUNCTION.isEnabled()) {
-            entries.add(Decay.ENTRY);
-        }
 
         return Collections.unmodifiableList(entries);
     }

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

@@ -124,7 +124,7 @@ public class Decay extends EsqlScalarFunction implements OptionalArgument, PostO
     @FunctionInfo(
         returnType = "double",
         preview = true,
-        appliesTo = { @FunctionAppliesTo(lifeCycle = FunctionAppliesToLifecycle.PREVIEW, version = "9.2.0") },
+        appliesTo = { @FunctionAppliesTo(lifeCycle = FunctionAppliesToLifecycle.PREVIEW, version = "9.3.0") },
         description = "Calculates a relevance score that decays based on the distance of a numeric, spatial or date type value "
             + "from a target origin, using configurable decay functions.",
         detailedDescription = """

x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/expression/function/scalar/score/Decay.java

@@ -2639,8 +2639,6 @@ public void testFullTextFunctionsInStats() {
     }
 
     public void testDecayArgs() {
-        assumeTrue("Decay function not enabled", EsqlCapabilities.Cap.DECAY_FUNCTION.isEnabled());
-
         // First arg cannot be null
         assertEquals(
             "2:23: first argument of [decay(null, origin, scale, "

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

@@ -13,7 +13,6 @@
 import org.elasticsearch.common.geo.GeoPoint;
 import org.elasticsearch.common.unit.DistanceUnit;
 import org.elasticsearch.script.ScoreScriptUtils;
-import org.elasticsearch.xpack.esql.action.EsqlCapabilities;
 import org.elasticsearch.xpack.esql.core.expression.Expression;
 import org.elasticsearch.xpack.esql.core.expression.Literal;
 import org.elasticsearch.xpack.esql.core.expression.MapExpression;
@@ -22,7 +21,6 @@
 import org.elasticsearch.xpack.esql.expression.function.AbstractScalarFunctionTestCase;
 import org.elasticsearch.xpack.esql.expression.function.TestCaseSupplier;
 import org.hamcrest.Matcher;
-import org.junit.BeforeClass;
 
 import java.math.BigDecimal;
 import java.math.RoundingMode;
@@ -49,11 +47,6 @@ public DecayTests(@Name("TestCase") Supplier<TestCaseSupplier.TestCase> testCase
         this.testCase = testCaseSupplier.get();
     }
 
-    @BeforeClass
-    public static void checkCapability() {
-        assumeTrue("Decay function tests require the DECAY_FUNCTION capability", EsqlCapabilities.Cap.DECAY_FUNCTION.isEnabled());
-    }
-
     @ParametersFactory
     public static Iterable<Object[]> parameters() {
         List<TestCaseSupplier> testCaseSuppliers = new ArrayList<>();

x-pack/plugin/esql/src/test/java/org/elasticsearch/xpack/esql/expression/function/scalar/score/DecayTests.java

@@ -9337,8 +9337,6 @@ public void testTranslateMetricsGroupedByTBucketInTSMode() {
     }
 
     public void testDecayOriginMustBeLiteral() {
-        assumeTrue("requires DECAY_FUNCTION capability enabled", EsqlCapabilities.Cap.DECAY_FUNCTION.isEnabled());
-
         var query = """
             FROM employees
             | EVAL decay_result = decay(salary, salary, 10, {"offset": 5, "decay": 0.5, "type": "linear"})
@@ -9353,8 +9351,6 @@ public void testDecayOriginMustBeLiteral() {
     }
 
     public void testDecayScaleMustBeLiteral() {
-        assumeTrue("requires DECAY_FUNCTION capability enabled", EsqlCapabilities.Cap.DECAY_FUNCTION.isEnabled());
-
         var query = """
             FROM employees
             | EVAL decay_result = decay(salary, 10, salary, {"offset": 5, "decay": 0.5, "type": "linear"})