#933 Add support for parenthesized queries to StatementDetector

Author: mrotteveel

src/docs/asciidoc/release_notes.adoc

@@ -666,6 +666,7 @@ The change also lead to incompatible changes to protected methods in the various
 See also https://github.com/FirebirdSQL/jaybird/blob/master/devdoc/jdp/jdp-2026-01-additional-locking-for-sending-in-wire-protocol.adoc[jdp-2026-01: Additional locking for sending in wire protocol].
 * Upgraded `org.firebirdsql.extern.decimal` to https://github.com/FirebirdSQL/decimal-java[decimal-java 2.0.1^]
 * Support `USING` clause in generated keys detection (https://github.com/FirebirdSQL/jaybird/issues/932[#932])
+* Add support for parenthesized queries to `StatementDetector` (https://github.com/FirebirdSQL/jaybird/issues/933[#933])
 * ...
 
 [#compatibility-changes]

src/main/org/firebirdsql/jaybird/parser/StatementDetector.java

@@ -48,6 +48,10 @@ public final class StatementDetector implements TokenVisitor {
         nextAfterStart.put("ROLLBACK",
                 new StateAfterStart(ParserState.COMMIT_ROLLBACK, LocalStatementType.HARD_ROLLBACK));
         nextAfterStart.put("SET", new StateAfterStart(ParserState.SET, LocalStatementType.OTHER));
+        // Firebird 5.0+ parenthesized query expression
+        // NOTE: This is a shortcut, if parenthesis at the top-level are ever allowed for anything other than SELECT (or
+        // SELECT-like statements), this needs to be reworked
+        nextAfterStart.put("(", new StateAfterStart(ParserState.SELECT, LocalStatementType.SELECT));
         // Firebird 6.0+ USING ... DO; need to find end of the USING clause to detect actual statement type
         nextAfterStart.put("USING", new StateAfterStart(ParserState.FIND_USING_END, LocalStatementType.OTHER));
         NEXT_AFTER_START = unmodifiableMap(nextAfterStart);
@@ -176,7 +180,7 @@ private enum ParserState {
         START {
             @Override
             ParserState next(Token token, StatementDetector detector) {
-                if (!(token instanceof ReservedToken)) {
+                if (!(token instanceof ReservedToken || token instanceof ParenthesisOpen)) {
                     return forceOther(detector);
                 }
                 StateAfterStart stateAfterStart =

src/test/org/firebirdsql/jaybird/parser/StatementDetectorTest.java

@@ -49,13 +49,20 @@ static Stream<Arguments> detectionCases() {
                 // SELECT
                 detectReturning("select * from RDB$DATABASE", LocalStatementType.SELECT, false),
                 noDetect("select * from RDB$DATABASE", LocalStatementType.SELECT, false),
-                detectReturning("/* a comment */ select * from RDB$DATABASE", LocalStatementType.SELECT, false),
+                                detectReturning("/* a comment */ select * from RDB$DATABASE", LocalStatementType.SELECT, false),
                 // Presence of select as first keyword is sufficient
                 detectReturning("select", LocalStatementType.SELECT, true),
                 detectReturning("with a as (select 1 as col from rdb$database) select * from a",
                         LocalStatementType.SELECT, false),
                 // Presence of with as first keyword is sufficient
                 detectReturning("with", LocalStatementType.SELECT, true),
+                detectReturning("(select * from RDB$DATABASE)", LocalStatementType.SELECT, false),
+
+                // SELECT: Parenthesized query expressions
+                noDetect("(select * from RDB$DATABASE)", LocalStatementType.SELECT, false),
+                noDetect("((select * from RDB$DATABASE))", LocalStatementType.SELECT, false),
+                // Presence of only the open parenthesis is sufficient
+                detectReturning("(", LocalStatementType.SELECT, true),
 
                 // EXECUTE PROCEDURE
                 detectReturning("execute procedure test 'value1', 'value2'",