Cross reference the cast matrix against openGauss pg_cast.h to confirm numeric_int4 dtoi4 ftoi4 bpchar and namein OIDs match PostgreSQL exactly while explicitly calling out the openGauss only bool to numeric and numeric to bool cast entries 6433 6434 that the evaluator deliberately treats as conservative narrowing since aligning with PostgreSQL rejection means routing falls through to broadcast on openGauss rather than picking the casted 0 or 1 value

Author: Phixsura

features/sharding/core/src/main/java/org/apache/shardingsphere/sharding/route/engine/condition/engine/PostgreSQLCastEvaluator.java

@@ -51,12 +51,19 @@
  * {@code bool::numeric}, {@code numeric::bool}, {@code float8::bool}, {@code '1.5'::int4} (PG raises
  * {@code invalid input syntax for type integer}).</p>
  *
- * <p>openGauss inherits its {@code pg_cast} catalog from PostgreSQL 9.2 and keeps the same {@code numeric_int4} /
- * {@code dtoi4} / {@code ftoi4} / {@code bpchar} / {@code namein} cast functions, so the cell-by-cell behavior
- * verified here against PostgreSQL 16 also describes the openGauss path. The evaluator is invoked only when the
- * parser produces a {@code TypeCastExpression}, which is emitted exclusively by the PostgreSQL and openGauss
- * visitors; MySQL / Oracle / SQL Server {@code CAST(...)} syntax becomes a {@code FunctionSegment} and bypasses
- * this evaluator entirely, so there is no cross-dialect contamination risk.</p>
+ * <p>openGauss forks the {@code pg_cast} catalog from PostgreSQL 9.2 (see
+ * {@code src/include/catalog/pg_cast.h} in {@code opengauss-mirror/openGauss-server}) and keeps the same OID-bound
+ * {@code numeric_int4} / {@code dtoi4} / {@code ftoi4} / {@code bpchar} / {@code namein} cast functions, so the
+ * integer / numeric / float / text / name behavior verified here against PostgreSQL 16 carries through unchanged.
+ * The one substantive divergence is the {@code bool ↔ numeric} pair: openGauss adds explicit cast functions
+ * {@code 6433} ({@code bool → numeric}) and {@code 6434} ({@code numeric → bool}) that PostgreSQL does not have, and
+ * this evaluator stays aligned with PostgreSQL by returning {@link Optional#empty()} for both, which on openGauss is
+ * a conservative narrowing: routing falls through to broadcast where openGauss could otherwise route by the casted
+ * 0 / 1 value. Implementing openGauss-aware optimization for those two cells is deferred and noted explicitly here.</p>
+ *
+ * <p>The evaluator is invoked only when the parser produces a {@code TypeCastExpression}, which is emitted
+ * exclusively by the PostgreSQL and openGauss visitors; MySQL / Oracle / SQL Server {@code CAST(...)} syntax becomes
+ * a {@code FunctionSegment} and bypasses this evaluator entirely, so there is no cross-dialect contamination risk.</p>
  */
 @NoArgsConstructor(access = AccessLevel.PRIVATE)
 public final class PostgreSQLCastEvaluator {

features/sharding/core/src/test/java/org/apache/shardingsphere/sharding/route/engine/condition/engine/PostgreSQLCastEvaluatorTest.java

@@ -411,6 +411,16 @@ void assertBooleanToBoolean() {
         assertThat(PostgreSQLCastEvaluator.evaluate(Boolean.TRUE, "bool").orElseThrow(AssertionError::new), is(Boolean.TRUE));
     }
 
+    @Test
+    void assertBoolToNumericIsConservativeOnOpenGaussWhichWouldAcceptThisCast() {
+        assertFalse(PostgreSQLCastEvaluator.evaluate(Boolean.TRUE, "numeric").isPresent());
+    }
+    
+    @Test
+    void assertNumericToBoolIsConservativeOnOpenGaussWhichWouldAcceptThisCast() {
+        assertFalse(PostgreSQLCastEvaluator.evaluate(new BigDecimal("1"), "bool").isPresent());
+    }
+    
     @Test
     void assertBooleanTrueToName() {
         assertThat(PostgreSQLCastEvaluator.evaluate(Boolean.TRUE, "name").orElseThrow(AssertionError::new), is("t"));