next correction of parenthesis around unions

Author: wumpz

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

@@ -1583,7 +1583,7 @@ SelectBody SetOperationList() #SetOperationList: {
 {
     (("(" select=SelectBody() ")" { bracket=true;} )
                     | ( select=PlainSelect() | select=Values() ) { bracket=false;} ) {selects.add(select);brackets.add(bracket); }   
-    (
+    ( LOOKAHEAD(2)
         ((<K_UNION> { UnionOp union = new UnionOp();linkAST(union,jjtThis);operations.add(union); } [ <K_ALL> { union.setAll(true); } | <K_DISTINCT> { union.setDistinct(true); } ])
         | <K_INTERSECT> { operations.add(new IntersectOp()); }
         | <K_MINUS> { operations.add(new MinusOp()); }
@@ -1618,23 +1618,33 @@ SelectBody SetOperationList() #SetOperationList: {
     }
 }
 
-SelectBody SetOperationListWithoutIntialSelect(SelectBody _select, boolean _bracket) #SetOperationList:
+SelectBody SetOperationListWithoutIntialSelect(FromItem fromItem) #SetOperationList:
 {
     SetOperationList list = new SetOperationList();
     List<OrderByElement> orderByElements = null;
     Limit limit = null;
     Offset offset = null;
     Fetch fetch = null;
-    SelectBody select = _select;
+    SelectBody select;
     List<SelectBody> selects = new ArrayList<SelectBody>();
     List<SetOperation> operations = new ArrayList<SetOperation>();
     List<Boolean> brackets = new ArrayList<Boolean>();
-    boolean bracket = _bracket;
+    boolean bracket = false;
 }
 {
     {
+        while (fromItem instanceof ParenthesisFromItem) {
+            fromItem = ((ParenthesisFromItem)fromItem).getFromItem();
+        }
+
+        if (fromItem instanceof SubSelect) {
+            select = ((SubSelect)fromItem).getSelectBody();
+        } else {
+            throw new IllegalArgumentException("this type of set operation is not allowed");
+        }
+
         selects.add(select);
-        brackets.add(bracket);
+        brackets.add(true);
     } 
     ( LOOKAHEAD(2) 
         ((<K_UNION> { UnionOp union = new UnionOp();linkAST(union,jjtThis);operations.add(union); } [ <K_ALL> { union.setAll(true); } | <K_DISTINCT> { union.setDistinct(true); } ])
@@ -2010,15 +2020,15 @@ FromItem FromItem():
                         | 
                         fromItem=SubSelect()
                         )
+                        [ selectBody = SetOperationListWithoutIntialSelect(fromItem) 
+                            {   
+                                if (!(selectBody instanceof PlainSelect)) {
+                                    fromItem = new SubSelect().withSelectBody(selectBody); 
+                                }
+                            }
+                        ]
                     ")"
                     [ LOOKAHEAD(2) unpivot=UnPivot() { fromItem.setUnPivot(unpivot); } ]
-                    [ LOOKAHEAD(2) selectBody = SetOperationListWithoutIntialSelect(((SubSelect)fromItem).getSelectBody(), true) 
-                        {   
-                            if (!(selectBody instanceof PlainSelect)) {
-                                fromItem = new SubSelect().withSelectBody(selectBody); 
-                            }
-                        }
-                    ]
                 )
                 |
                 LOOKAHEAD(TableFunction())

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

@@ -4408,4 +4408,27 @@ public void testH2CaseWhenFunctionIssue1091() throws JSQLParserException {
     public void testMultiPartTypesIssue992() throws JSQLParserException {
         assertSqlCanBeParsedAndDeparsed("SELECT CAST('*' AS pg_catalog.text)");
     }
+    
+    @Test
+    public void testSetOperationWithParenthesisIssue1094() throws JSQLParserException {
+        assertSqlCanBeParsedAndDeparsed("SELECT * FROM ((SELECT A FROM tbl) UNION DISTINCT (SELECT B FROM tbl2)) AS union1");
+    }
+    
+    @Test
+    public void testSetOperationWithParenthesisIssue1094_2() throws JSQLParserException {
+        Statement stmt = CCJSqlParserUtil.parse("SELECT * FROM (((SELECT A FROM tbl)) UNION DISTINCT (SELECT B FROM tbl2)) AS union1");
+        assertEquals("SELECT * FROM ((SELECT A FROM tbl) UNION DISTINCT (SELECT B FROM tbl2)) AS union1", stmt.toString());
+    }
+    
+    @Test
+    public void testSetOperationWithParenthesisIssue1094_3() throws JSQLParserException {
+        Statement stmt = CCJSqlParserUtil.parse("SELECT * FROM (((SELECT A FROM tbl)) UNION DISTINCT ((SELECT B FROM tbl2))) AS union1");
+        assertEquals("SELECT * FROM ((SELECT A FROM tbl) UNION DISTINCT ((SELECT B FROM tbl2))) AS union1", stmt.toString());
+    }
+    
+    @Test
+    public void testSetOperationWithParenthesisIssue1094_4() throws JSQLParserException {
+        Statement stmt = CCJSqlParserUtil.parse("SELECT * FROM (((((SELECT A FROM tbl)))) UNION DISTINCT (((((((SELECT B FROM tbl2)))))))) AS union1");
+        assertEquals("SELECT * FROM ((SELECT A FROM tbl) UNION DISTINCT ((SELECT B FROM tbl2))) AS union1", stmt.toString());
+    }
 }