Remove the 500-token cap from the nested set operation lookahead (#2780)

isNestedSetOperationAhead() gave up after 500 tokens, so a parenthesised
set operation whose first branch is longer than that was parsed as a
parenthesised FROM item and failed on the set operator. Walk the token
chain once instead of calling getToken(i) per position, which removes
the need for a cap.

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

Author: edeadington

src/main/jjtree/net/sf/jsqlparser/parser/JSqlParserCC.jjt

@@ -765,27 +765,12 @@ public class CCJSqlParser extends AbstractJSqlParser<CCJSqlParser> {
             if (getToken(1).kind != OPENING_BRACKET) return false;
             if (getToken(2).kind != OPENING_BRACKET) return false;
             // Skip any run of opening brackets: ( ( ( ... ( SELECT
-            int i = 3;
-            while (getToken(i).kind == OPENING_BRACKET) i++;
-            int k = getToken(i).kind;
-            if (k != K_SELECT && k != K_WITH && k != K_VALUES) return false;
-            // Scan forward counting brackets to find the matching ) for token(2)
-            // We are now inside all the opening brackets; depth = number of brackets skipped - 1
-            // (token(1) is the outer one, token(2..i-1) are the inner ones we scanned)
-            int depth = i - 2; // brackets from position 2 to i-1 inclusive
-            i++;
-            while (i <= 500) {
-                Token t; try { t = getToken(i); } catch (TokenMgrException e) { return false; }
-                if (t == null || t.kind == 0) return false;
-                if (t.kind == OPENING_BRACKET) depth++;
-                else if (t.kind == CLOSING_BRACKET) {
-                    if (--depth == 0) break;
-                }
-                i++;
-            }
-            if (i > 500) return false;
-            // Token at position i+1 follows the innermost closing )
-            Token next; try { next = getToken(i + 1); } catch (TokenMgrException e) { return false; }
+            Token innerOpen = getToken(2);
+            Token t = innerOpen;
+            while (t.kind == OPENING_BRACKET) t = nextWithItemToken(t);
+            if (t.kind != K_SELECT && t.kind != K_WITH && t.kind != K_VALUES) return false;
+            // Follow the token chain directly; repeated getToken(i) calls rescan from the start each time
+            Token next = skipBalancedBracketGroup(innerOpen);
             if (next == null) return false;
             return next.kind == K_UNION || next.kind == K_INTERSECT ||
                    next.kind == K_EXCEPT || next.kind == K_MINUS;

src/test/java/net/sf/jsqlparser/statement/select/SelectTest.java

@@ -91,6 +91,8 @@
 @Execution(ExecutionMode.CONCURRENT)
 public class SelectTest {
 
+    private static final String LONG_CONDITION = "B = 1 AND ".repeat(150) + "B = 1";
+
     private final CCJSqlParserManager parserManager = new CCJSqlParserManager();
 
     @Test
@@ -5362,6 +5364,18 @@ public void testSetOperationWithParenthesisIssue1094() throws JSQLParserExceptio
                 "SELECT * FROM ((SELECT A FROM tbl) UNION DISTINCT (SELECT B FROM tbl2)) AS union1");
     }
 
+    @Test
+    public void testSetOperationWithParenthesisAndLongFirstBranch() throws JSQLParserException {
+        assertSqlCanBeParsedAndDeparsed("SELECT * FROM ((SELECT A FROM tbl WHERE " + LONG_CONDITION
+                + ") UNION ALL (SELECT A FROM tbl2)) AS union1");
+    }
+
+    @Test
+    public void testSetOperationInExpressionWithLongFirstBranch() throws JSQLParserException {
+        assertSqlCanBeParsedAndDeparsed("SELECT * FROM tbl WHERE A IN ((SELECT A FROM tbl2 WHERE "
+                + LONG_CONDITION + ") UNION ALL (SELECT A FROM tbl3))");
+    }
+
     @Test
     public void testSetOperationWithParenthesisIssue1094_2() throws JSQLParserException {
         String sqlStr =