[ES|QL] Take TOP_SNIPPETS out of snapshot

docs/changelog/139272.yaml

@@ -0,0 +1,5 @@
+pr: 139272
+summary: ES|QL - Add TOP_SNIPPETS as tech preview
+area: ES|QL
+type: enhancement
+issues: []

docs/reference/query-languages/esql/_snippets/lists/search-functions.md

@@ -1,6 +1,8 @@
+* [`DECAY`](../../functions-operators/search-functions.md#esql-decay) {applies_to}`stack: preview` {applies_to}`serverless: preview`
 * [`KQL`](../../functions-operators/search-functions.md#esql-kql)
 * [`MATCH`](../../functions-operators/search-functions.md#esql-match)
 * [`MATCH_PHRASE`](../../functions-operators/search-functions.md#esql-match_phrase)
 * [`QSTR`](../../functions-operators/search-functions.md#esql-qstr)
-% * [`DECAY`](../../functions-operators/search-functions.md#esql-decay) {applies_to}`stack: preview` {applies_to}`serverless: preview`
+* [`SCORE`](../../functions-operators/search-functions.md#esql-score) {applies_to}`stack: preview` {applies_to}`serverless: preview`
 % * [`TERM`](../../functions-operators/search-functions.md#esql-term) {applies_to}`stack: preview` {applies_to}`serverless: preview`
+* [`TOP_SNIPPETS`](../../functions-operators/search-functions.md#esql-top_snippets) {applies_to}`stack: preview` {applies_to}`serverless: preview`

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

@@ -40,6 +40,8 @@ for information on the limitations of full text search.
 :::{include} ../_snippets/lists/search-functions.md
 :::
 
+:::{include} ../_snippets/functions/layout/decay.md
+:::
 
 :::{include} ../_snippets/functions/layout/kql.md
 :::
@@ -56,7 +58,7 @@ for information on the limitations of full text search.
 :::{include} ../_snippets/functions/layout/score.md
 :::
 
-:::{include} ../_snippets/functions/layout/decay.md
+:::{include} ../_snippets/functions/layout/top_snippets.md
 :::
 
 % TERM is currently a hidden feature

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

@@ -1737,7 +1737,7 @@ public enum Cap {
         /**
          * Returns the top snippets for given text content and associated query.
          */
-        TOP_SNIPPETS_FUNCTION(Build.current().isSnapshot()),
+        TOP_SNIPPETS_FUNCTION,
 
         // Last capability should still have a comma for fewer merge conflicts when adding new ones :)
         // This comment prevents the semicolon from being on the previous capability when Spotless formats the file.

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

@@ -527,7 +527,7 @@ private static FunctionDefinition[][] functions() {
                 def(MvZip.class, MvZip::new, "mv_zip"),
                 def(MvSum.class, MvSum::new, "mv_sum"),
                 def(Split.class, Split::new, "split") },
-            // fulltext functions
+            // search functions
             new FunctionDefinition[] {
                 def(Decay.class, quad(Decay::new), "decay"),
                 def(Kql.class, bic(Kql::new), "kql"),
@@ -536,7 +536,8 @@ private static FunctionDefinition[][] functions() {
                 def(MultiMatch.class, MultiMatch::new, "multi_match"),
                 def(QueryString.class, bic(QueryString::new), "qstr"),
                 def(MatchPhrase.class, tri(MatchPhrase::new), "match_phrase"),
-                def(Score.class, uni(Score::new), "score") },
+                def(Score.class, uni(Score::new), "score"),
+                def(TopSnippets.class, tri(TopSnippets::new), "top_snippets") },
             // time-series functions
             new FunctionDefinition[] {
                 defTS3(Rate.class, Rate::new, "rate"),
@@ -578,8 +579,7 @@ private static FunctionDefinition[][] snapshotFunctions() {
                 def(L1Norm.class, L1Norm::new, "v_l1_norm"),
                 def(L2Norm.class, L2Norm::new, "v_l2_norm"),
                 def(Magnitude.class, Magnitude::new, "v_magnitude"),
-                def(Hamming.class, Hamming::new, "v_hamming"),
-                def(TopSnippets.class, tri(TopSnippets::new), "top_snippets") } };
+                def(Hamming.class, Hamming::new, "v_hamming") } };
     }
 
     public EsqlFunctionRegistry snapshotRegistry() {

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

@@ -3335,8 +3335,6 @@ public void testChunkFunctionInvalidInputs() {
     }
 
     public void testTopSnippetsFunctionInvalidInputs() {
-        assumeTrue("Requires top snippet function", EsqlCapabilities.Cap.TOP_SNIPPETS_FUNCTION.isEnabled());
-
         // Null field allowed
         query("from test | EVAL snippets = TOP_SNIPPETS(null, \"query\")");