[plsql] Parse Exception with EXISTS

Fixes #1587

docs/pages/release_notes.md

@@ -37,6 +37,8 @@ This is a {{ site.pmd.release_type }} release.
     *   [#1633](https://github.com/pmd/pmd/issues/1633): \[java] UnsynchronizedStaticFormatter reports commons lang FastDateFormat
 *   java-performance
     *   [#1632](https://github.com/pmd/pmd/issues/1632): \[java] ConsecutiveLiteralAppends false positive over catch
+*   plsql
+    *   [#1587](https://github.com/pmd/pmd/issues/1587): \[plsql] Parse Exception with EXISTS
 
 ### API Changes
 

pmd-plsql/etc/grammar/PldocAST.jjt

@@ -1314,6 +1314,8 @@ void Condition2() #void :
     LOOKAHEAD(4) IsNullCondition()
  |
     LOOKAHEAD(4) IsOfTypeCondition()
+ |
+    ExistsCondition()
  )
 }
 
@@ -1338,6 +1340,14 @@ ASTLikeCondition LikeCondition() :
     { return jjtThis; }
 }
 
+ASTExistsCondition ExistsCondition() :
+{}
+{
+    <EXISTS> "(" Subquery() ")"
+
+    { return jjtThis; }
+}
+
 ASTCompoundCondition CompoundCondition() :
 {}
 {
@@ -5848,7 +5858,7 @@ ASTID ID(): {}
 		| <EXCEPTION> //SYNTAX
 		| <EXCLUSIVE> //SYNTAX //RESERVED WORD
 		| <EXECUTE> //SYNTAX
-		| <EXISTS> //SYNTAX //RESERVED WORD
+		//| <EXISTS> //SYNTAX //RESERVED WORD
 		//| <EXIT> //SYNTAX
 		//20120501 | <EXTENDS>
 		| <FETCH> //SYNTAX

pmd-plsql/src/main/java/net/sourceforge/pmd/lang/plsql/ast/PLSQLParserVisitorAdapter.java

@@ -986,4 +986,9 @@ public class PLSQLParserVisitorAdapter implements PLSQLParserVisitor {
     public Object visit(ASTValuesClause node, Object data) {
         return visit((PLSQLNode) node, data);
     }
+
+    @Override
+    public Object visit(ASTExistsCondition node, Object data) {
+        return visit((PLSQLNode) node, data);
+    }
 }

pmd-plsql/src/main/java/net/sourceforge/pmd/lang/plsql/rule/AbstractPLSQLRule.java

@@ -1080,6 +1080,11 @@ public abstract class AbstractPLSQLRule extends AbstractRule implements PLSQLPar
         return visit((PLSQLNode) node, data);
     }
 
+    @Override
+    public Object visit(ASTExistsCondition node, Object data) {
+        return visit((PLSQLNode) node, data);
+    }
+
     /*
      * Treat all Executable Code
      */

pmd-plsql/src/test/java/net/sourceforge/pmd/lang/plsql/ast/WhereClauseTest.java

@@ -68,4 +68,11 @@ public class WhereClauseTest extends AbstractPLSQLParserTst {
                 StandardCharsets.UTF_8);
         ASTInput input = parsePLSQL(code);
     }
+
+    @Test
+    public void testExistsCondition() throws Exception {
+        String code = IOUtils.toString(this.getClass().getResourceAsStream("WhereClauseExists.pls"),
+                StandardCharsets.UTF_8);
+        ASTInput input = parsePLSQL(code);
+    }
 }

pmd-plsql/src/test/resources/net/sourceforge/pmd/lang/plsql/ast/WhereClauseExists.pls

@@ -0,0 +1,24 @@
+--
+-- Where Clause With Exists Condition
+-- https://docs.oracle.com/en/database/oracle/oracle-database/18/sqlrf/EXISTS-Condition.html#GUID-20259A83-C42B-4E0D-8DF4-9A2A66ACA8E7
+--
+
+BEGIN
+
+SELECT id
+  INTO id_out
+  FROM some_table
+  WHERE EXISTS
+    (SELECT NULL
+     FROM other_table
+     WHERE other_id = other_id_in);
+
+DELETE FROM some_table
+  WHERE id = id_in
+  AND NOT EXISTS
+    (SELECT NULL
+     FROM other_table
+     WHERE id = id_in);
+
+END;
+/