Move ES|QL sample command from snapshot to tech preview (elastic#129540)

* Move ES|QL sample command from snapshot to tech preview

* dev_sample -> sample

* fix test

* fix grammar

Author: jan-elastic

x-pack/plugin/esql/qa/server/src/main/java/org/elasticsearch/xpack/esql/qa/rest/RestEsqlTestCase.java

@@ -794,7 +794,7 @@ public void testNamedParamsForIdentifierAndIdentifierPatterns() throws IOExcepti
             error = re.getMessage();
             assertThat(error, containsString("ParsingException"));
             assertThat(error, containsString("line 1:23: mismatched input '?cmd' expecting {"));
-            assertThat(error, containsString("'dissect', 'eval', 'grok', 'limit', 'sort'"));
+            assertThat(error, containsString("'dissect', 'eval', 'grok', 'limit', 'sample', 'sort'"));
         }
     }
 

x-pack/plugin/esql/src/main/antlr/EsqlBaseLexer.tokens

@@ -57,14 +57,14 @@ processingCommand
     | joinCommand
     | changePointCommand
     | completionCommand
+    | sampleCommand
     // in development
     | {this.isDevVersion()}? inlinestatsCommand
     | {this.isDevVersion()}? lookupCommand
     | {this.isDevVersion()}? insistCommand
     | {this.isDevVersion()}? forkCommand
     | {this.isDevVersion()}? rerankCommand
     | {this.isDevVersion()}? rrfCommand
-    | {this.isDevVersion()}? sampleCommand
     ;
 
 whereCommand
@@ -258,6 +258,10 @@ enrichWithClause
     : (newName=qualifiedNamePattern ASSIGN)? enrichField=qualifiedNamePattern
     ;
 
+sampleCommand
+    : SAMPLE probability=constant
+    ;
+
 //
 // In development
 //
@@ -309,7 +313,3 @@ rerankCommand
 completionCommand
     : COMPLETION (targetField=qualifiedName ASSIGN)? prompt=primaryExpression WITH inferenceId=identifierOrParameter
     ;
-
-sampleCommand
-    : DEV_SAMPLE probability=constant
-    ;

x-pack/plugin/esql/src/main/antlr/EsqlBaseParser.g4

@@ -15,13 +15,13 @@ EVAL : 'eval'                 -> pushMode(EXPRESSION_MODE);
 GROK : 'grok'                 -> pushMode(EXPRESSION_MODE);
 LIMIT : 'limit'               -> pushMode(EXPRESSION_MODE);
 ROW : 'row'                   -> pushMode(EXPRESSION_MODE);
+SAMPLE : 'sample'             -> pushMode(EXPRESSION_MODE);
 SORT : 'sort'                 -> pushMode(EXPRESSION_MODE);
 STATS : 'stats'               -> pushMode(EXPRESSION_MODE);
 WHERE : 'where'               -> pushMode(EXPRESSION_MODE);
 
 DEV_INLINESTATS : {this.isDevVersion()}? 'inlinestats' -> pushMode(EXPRESSION_MODE);
 DEV_RERANK : {this.isDevVersion()}? 'rerank'           -> pushMode(EXPRESSION_MODE);
-DEV_SAMPLE : {this.isDevVersion()}? 'sample'           -> pushMode(EXPRESSION_MODE);
 
 
 mode EXPRESSION_MODE;

x-pack/plugin/esql/src/main/antlr/EsqlBaseParser.tokens

@@ -1082,7 +1082,7 @@ public enum Cap {
         /**
          * Support for the SAMPLE command
          */
-        SAMPLE_V3(Build.current().isSnapshot()),
+        SAMPLE_V3,
 
         /**
          * The {@code _query} API now gives a cast recommendation if multiple types are found in certain instances.
@@ -1207,7 +1207,7 @@ public enum Cap {
         /**
          * Support parameters for SAMPLE command.
          */
-        PARAMETER_FOR_SAMPLE(Build.current().isSnapshot()),
+        PARAMETER_FOR_SAMPLE,
 
         /**
          * From now, Literal only accepts strings as BytesRefs.