From 6409fd79aeb570709ea8b6a2f11182a1aea4240c Mon Sep 17 00:00:00 2001
From: Vadim Kibana <82822460+vadimkibana@users.noreply.github.com>
Date: Tue, 1 Jul 2025 15:50:01 +0200
Subject: [PATCH] [ES|QL] Stop ANTLR token monkey-patching in parser (#225629)

## Summary

A small cleanup in parser code in the ES|QL AST package. We want to show
users readable syntax error token names like `[` and `(` (instead of
`LP`), however, we should not monkey-patch ANTLR generated files to
achieve this. Instead, this PR moves the message improvement code to the
validation & autocomplete package, where the messages are actually used.

### Checklist

- [x] [Unit or functional
tests](https://www.elastic.co/guide/en/kibana/master/development-tests.html)
were updated or added to match the most common scenarios

(cherry picked from commit 750cc7c4c1b91f2713b97a27c89e07dadffbb816)
---
 .../shared/kbn-esql-ast/src/parser/parser.ts  | 28 +------------------
 .../src/validation/validation.ts              |  9 +++++-
 2 files changed, 9 insertions(+), 28 deletions(-)

diff --git a/src/platform/packages/shared/kbn-esql-ast/src/parser/parser.ts b/src/platform/packages/shared/kbn-esql-ast/src/parser/parser.ts
index c6eeb8b7214c7..334c2fdbf6b36 100644
--- a/src/platform/packages/shared/kbn-esql-ast/src/parser/parser.ts
+++ b/src/platform/packages/shared/kbn-esql-ast/src/parser/parser.ts
@@ -13,33 +13,10 @@ import { ESQLErrorListener } from './esql_error_listener';
 import { ESQLAstBuilderListener } from './esql_ast_builder_listener';
 import { GRAMMAR_ROOT_RULE } from './constants';
 import { attachDecorations, collectDecorations } from './formatting';
-import type { ESQLAst, ESQLAstQueryExpression, EditorError } from '../types';
 import { Builder } from '../builder';
 import { default as ESQLLexer } from '../antlr/esql_lexer';
 import { default as ESQLParser } from '../antlr/esql_parser';
-
-/**
- * Some changes to the grammar deleted the literal names for some tokens.
- * This is a workaround to restore the literals that were lost.
- *
- * See https://github.com/elastic/elasticsearch/pull/124177 for context.
- */
-const replaceSymbolsWithLiterals = (
-  symbolicNames: Array<string | null>,
-  literalNames: Array<string | null>
-) => {
-  const symbolReplacements: Map<string, string> = new Map([
-    ['LP', '('],
-    ['OPENING_BRACKET', '['],
-  ]);
-
-  for (let i = 0; i < symbolicNames.length; i++) {
-    const name = symbolicNames[i];
-    if (name && symbolReplacements.has(name)) {
-      literalNames[i] = `'${symbolReplacements.get(name)!}'`;
-    }
-  }
-};
+import type { ESQLAst, ESQLAstQueryExpression, EditorError } from '../types';
 
 export interface ParseOptions {
   /**
@@ -100,9 +77,6 @@ export class Parser {
     const tokens = (this.tokens = new CommonTokenStream(lexer));
     const parser = (this.parser = new ESQLParser(tokens));
 
-    replaceSymbolsWithLiterals(lexer.symbolicNames, lexer.literalNames);
-    replaceSymbolsWithLiterals(parser.symbolicNames, parser.literalNames);
-
     lexer.removeErrorListeners();
     lexer.addErrorListener(this.errors);
 
diff --git a/src/platform/packages/shared/kbn-esql-validation-autocomplete/src/validation/validation.ts b/src/platform/packages/shared/kbn-esql-validation-autocomplete/src/validation/validation.ts
index 2280ca3d531c6..1095430cb5576 100644
--- a/src/platform/packages/shared/kbn-esql-validation-autocomplete/src/validation/validation.ts
+++ b/src/platform/packages/shared/kbn-esql-validation-autocomplete/src/validation/validation.ts
@@ -194,8 +194,15 @@ async function validateAst(
     messages.push(...commandMessages);
   }
 
+  const parserErrors = parsingResult.errors;
+
+  for (const error of parserErrors) {
+    error.message = error.message.replace(/\bLP\b/, "'('");
+    error.message = error.message.replace(/\bOPENING_BRACKET\b/, "'['");
+  }
+
   return {
-    errors: [...parsingResult.errors, ...messages.filter(({ type }) => type === 'error')],
+    errors: [...parserErrors, ...messages.filter(({ type }) => type === 'error')],
     warnings: messages.filter(({ type }) => type === 'warning'),
   };
 }