Add support for parameters in LIMIT command (elastic#128464) (elastic#128655)

Author: luigidellaquila

docs/changelog/128464.yaml

@@ -0,0 +1,5 @@
+pr: 128464
+summary: Add support for parameters in LIMIT command
+area: ES|QL
+type: enhancement
+issues: []

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

@@ -244,7 +244,7 @@ identifierOrParameter
     ;
 
 limitCommand
-    : LIMIT INTEGER_LITERAL
+    : LIMIT constant
     ;
 
 sortCommand

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

@@ -893,7 +893,12 @@ public enum Cap {
         /**
          * Guards a bug fix matching {@code TO_LOWER(f) == ""}.
          */
-        TO_LOWER_EMPTY_STRING;
+        TO_LOWER_EMPTY_STRING,
+
+        /**
+         * Support parameters for LiMIT command.
+         */
+        PARAMETER_FOR_LIMIT;
 
         private final boolean enabled;
 

x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/parser/EsqlBaseParser.interp

@@ -85,12 +85,10 @@
 import static org.elasticsearch.xpack.esql.parser.ParserUtils.typedParsing;
 import static org.elasticsearch.xpack.esql.parser.ParserUtils.visitList;
 import static org.elasticsearch.xpack.esql.plan.logical.Enrich.Mode;
-import static org.elasticsearch.xpack.esql.type.EsqlDataTypeConverter.stringToInt;
 
 /**
  * Translates what we get back from Antlr into the data structures the rest of the planner steps will act on.  Generally speaking, things
  * which change the grammar will need to make changes here as well.
- *
  */
 public class LogicalPlanBuilder extends ExpressionBuilder {
 
@@ -372,8 +370,18 @@ public PlanFactory visitWhereCommand(EsqlBaseParser.WhereCommandContext ctx) {
     @Override
     public PlanFactory visitLimitCommand(EsqlBaseParser.LimitCommandContext ctx) {
         Source source = source(ctx);
-        int limit = stringToInt(ctx.INTEGER_LITERAL().getText());
-        return input -> new Limit(source, new Literal(source, limit, DataType.INTEGER), input);
+        Object val = expression(ctx.constant()).fold(FoldContext.small() /* TODO remove me */);
+        if (val instanceof Integer i) {
+            if (i < 0) {
+                throw new ParsingException(source, "Invalid value for LIMIT [" + val + "], expecting a non negative integer");
+            }
+            return input -> new Limit(source, new Literal(source, i, DataType.INTEGER), input);
+        } else {
+            throw new ParsingException(
+                source,
+                "Invalid value for LIMIT [" + val + ": " + val.getClass().getSimpleName() + "], expecting a non negative integer"
+            );
+        }
     }
 
     @Override

x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/parser/EsqlBaseParser.java

@@ -161,6 +161,12 @@ private String functionName(EsqlFunctionRegistry registry, Expression functionCa
         throw new IllegalArgumentException("can't find name for " + functionCall);
     }
 
+    public void testInvalidLimit() {
+        assertEquals("1:13: Invalid value for LIMIT [foo: String], expecting a non negative integer", error("row a = 1 | limit \"foo\""));
+        assertEquals("1:13: Invalid value for LIMIT [1.2: Double], expecting a non negative integer", error("row a = 1 | limit 1.2"));
+        assertEquals("1:13: Invalid value for LIMIT [-1], expecting a non negative integer", error("row a = 1 | limit -1"));
+    }
+
     private String error(String query) {
         ParsingException e = expectThrows(ParsingException.class, () -> defaultAnalyzer.analyze(parser.createStatement(query)));
         String message = e.getMessage();

x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/parser/LogicalPlanBuilder.java

@@ -885,7 +885,7 @@ public void testBasicLimitCommand() {
     }
 
     public void testLimitConstraints() {
-        expectError("from text | limit -1", "line 1:19: extraneous input '-' expecting INTEGER_LITERAL");
+        expectError("from text | limit -1", "line 1:13: Invalid value for LIMIT [-1], expecting a non negative integer");
     }
 
     public void testBasicSortCommand() {
@@ -3051,7 +3051,7 @@ public void testNamedFunctionArgumentInInvalidPositions() {
             Map.entry("drop {}", "line 1:18: token recognition error at: '{'"),
             Map.entry("rename a as {}", "line 1:25: token recognition error at: '{'"),
             Map.entry("mv_expand {}", "line 1:23: token recognition error at: '{'"),
-            Map.entry("limit {}", "line 1:19: mismatched input '{' expecting INTEGER_LITERAL"),
+            Map.entry("limit {}", "line 1:19: extraneous input '{' expecting {QUOTED_STRING"),
             Map.entry("enrich idx2 on f1 with f2 = {}", "line 1:41: token recognition error at: '{'"),
             Map.entry("dissect {} \"%{bar}\"", "line 1:21: extraneous input '{' expecting {QUOTED_STRING, INTEGER_LITERAL"),
             Map.entry("grok {} \"%{WORD:foo}\"", "line 1:18: extraneous input '{' expecting {QUOTED_STRING, INTEGER_LITERAL")