Fix broken join conditions with InlineQuery.

Before this fix, whenever a column of an inline query was rendered the `InlineQuery` and all its children were visited, resulting in spurious output.
This is no prevented by injecting a NoopVisitor.

Closes: #1362
Original pull request: #1368

Author: schauder

spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/render/ComparisonVisitor.java

@@ -39,7 +39,9 @@ class ComparisonVisitor extends FilteredSubtreeVisitor {
 	private @Nullable PartRenderer current;
 
 	ComparisonVisitor(RenderContext context, Comparison condition, RenderTarget target) {
+
 		super(it -> it == condition);
+
 		this.condition = condition;
 		this.target = target;
 		this.context = context;
@@ -52,12 +54,6 @@ class ComparisonVisitor extends FilteredSubtreeVisitor {
 	@Override
 	Delegation enterNested(Visitable segment) {
 
-		if (segment instanceof Condition) {
-			ConditionVisitor visitor = new ConditionVisitor(context);
-			current = visitor;
-			return Delegation.delegateTo(visitor);
-		}
-
 		if (segment instanceof Expression) {
 			ExpressionVisitor visitor = new ExpressionVisitor(context);
 			current = visitor;

spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/render/ExpressionVisitor.java

@@ -131,6 +131,11 @@ Delegation enterNested(Visitable segment) {
 			return Delegation.delegateTo(visitor);
 		}
 
+		if (segment instanceof InlineQuery) {
+
+			NoopVisitor<InlineQuery> partRenderer = new NoopVisitor(InlineQuery.class);
+			return Delegation.delegateTo(partRenderer);
+		}
 		return super.enterNested(segment);
 	}
 

spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/render/NoopVisitor.java

@@ -0,0 +1,26 @@
+/*
+ * Copyright 2022 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.data.relational.core.sql.render;
+
+
+import org.springframework.data.relational.core.sql.Visitable;
+
+class NoopVisitor<T extends Visitable> extends TypedSubtreeVisitor<T> {
+	NoopVisitor(Class<T> type) {
+		super(type);
+	}
+}

spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/render/TypedSubtreeVisitor.java

@@ -53,6 +53,13 @@ abstract class TypedSubtreeVisitor<T extends Visitable> extends DelegatingVisito
 		this.type = ResolvableType.forClass(getClass()).as(TypedSubtreeVisitor.class).getGeneric(0);
 	}
 
+	/**
+	 * Creates a new {@link TypedSubtreeVisitor} with an explicitly provided type.
+	 */
+	TypedSubtreeVisitor(Class <T> type) {
+		this.type = ResolvableType.forType(type);
+	}
+
 	/**
 	 * {@link Visitor#enter(Visitable) Enter} callback for a {@link Visitable} that this {@link Visitor} is responsible
 	 * for. The default implementation retains delegation by default.