Support empty BooleanBuilder in QueryDSL adapter. [bug]

Author: michael-simons

neo4j-cypher-dsl/src/main/java/org/neo4j/cypherdsl/core/QueryDSLAdapter.java

@@ -25,6 +25,7 @@
 import org.neo4j.cypherdsl.core.querydsl.CypherContext;
 import org.neo4j.cypherdsl.core.querydsl.ToCypherFormatStringVisitor;
 
+import com.querydsl.core.BooleanBuilder;
 import com.querydsl.core.types.Path;
 import com.querydsl.core.types.Predicate;
 
@@ -54,6 +55,10 @@ public Condition asCondition() {
 			throw new IllegalArgumentException("Only Query-DSL predicates can be turned into Cypher-DSL's predicates.");
 		}
 
+		if (expression instanceof BooleanBuilder && !((BooleanBuilder) expression).hasValue()) {
+			return Conditions.noCondition();
+		}
+
 		CypherContext context = new CypherContext();
 		String formatString = expression.accept(ToCypherFormatStringVisitor.INSTANCE, context);
 

neo4j-cypher-dsl/src/test/java/org/neo4j/cypherdsl/core/querydsl/QueryDSLAdapterTest.java

@@ -50,6 +50,7 @@
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.Arguments;
 import org.junit.jupiter.params.provider.MethodSource;
+import org.neo4j.cypherdsl.core.Condition;
 import org.neo4j.cypherdsl.core.Cypher;
 import org.neo4j.cypherdsl.core.Literal.UnsupportedLiteralException;
 import org.neo4j.cypherdsl.core.Statement;
@@ -462,4 +463,32 @@ void shouldNotAdaptArbitraryThingsAsNames() {
 		assertThatIllegalArgumentException().isThrownBy(() -> Cypher.adapt(Expressions.TWO).asName())
 			.withMessage("Only Query-DSL paths can be turned into names.");
 	}
+
+	@Test
+	void emptyBooleanBuilder() {
+
+		Condition condition = Cypher.adapt(new BooleanBuilder()).asCondition();
+		Statement statement = Cypher.match(Cypher.anyNode().named("n"))
+			.where(condition)
+			.returning(Cypher.name("n"))
+			.build();
+
+		assertThat(statement.getParameterNames()).isEmpty();
+		assertThat(statement.getCypher())
+			.isEqualTo("MATCH (n) RETURN n");
+	}
+
+	@Test
+	void booleanBuilder() {
+
+		Condition condition = Cypher.adapt(new BooleanBuilder().and(Expressions.FALSE).and(Expressions.TRUE)).asCondition();
+		Statement statement = Cypher.match(Cypher.anyNode().named("n"))
+			.where(condition)
+			.returning(Cypher.name("n"))
+			.build();
+
+		assertThat(statement.getParameterNames()).isEmpty();
+		assertThat(statement.getCypher())
+			.isEqualTo("MATCH (n) WHERE false AND true RETURN n");
+	}
 }