Fix invalid String representation for composed RequestPredicates

Issue: SPR-17594

Author: poutsma

spring-webflux/src/main/java/org/springframework/web/reactive/function/server/RequestPredicates.java

@@ -370,11 +370,18 @@ public interface Visitor {
 		/**
 		 * Receive first notification of a logical AND predicate.
 		 * The first subsequent notification will contain the left-hand side of the AND-predicate;
-		 * the second notification contains the right-hand side, followed by {@link #endAnd()}.
+		 * followed by {@link #and()}, followed by the right-hand side, followed by {@link #endAnd()}.
 		 * @see RequestPredicate#and(RequestPredicate)
 		 */
 		void startAnd();
 
+		/**
+		 * Receive "middle" notification of a logical AND predicate.
+		 * The following notification contains the right-hand side, followed by {@link #endAnd()}.
+		 * @see RequestPredicate#and(RequestPredicate)
+		 */
+		void and();
+
 		/**
 		 * Receive last notification of a logical AND predicate.
 		 * @see RequestPredicate#and(RequestPredicate)
@@ -389,6 +396,13 @@ public interface Visitor {
 		 */
 		void startOr();
 
+		/**
+		 * Receive "middle" notification of a logical OR predicate.
+		 * The following notification contains the right-hand side, followed by {@link #endOr()}.
+		 * @see RequestPredicate#or(RequestPredicate)
+		 */
+		void or();
+
 		/**
 		 * Receive last notification of a logical OR predicate.
 		 * @see RequestPredicate#or(RequestPredicate)
@@ -750,6 +764,7 @@ public Optional<ServerRequest> nest(ServerRequest request) {
 		public void accept(Visitor visitor) {
 			visitor.startAnd();
 			this.left.accept(visitor);
+			visitor.and();
 			this.right.accept(visitor);
 			visitor.endAnd();
 		}
@@ -843,6 +858,7 @@ public Optional<ServerRequest> nest(ServerRequest request) {
 		public void accept(Visitor visitor) {
 			visitor.startOr();
 			this.left.accept(visitor);
+			visitor.or();
 			this.right.accept(visitor);
 			visitor.endOr();
 		}

spring-webflux/src/main/java/org/springframework/web/reactive/function/server/ToStringVisitor.java

@@ -23,7 +23,6 @@
 
 import org.springframework.core.io.Resource;
 import org.springframework.http.HttpMethod;
-import org.springframework.lang.Nullable;
 
 /**
  * Implementation of {@link RouterFunctions.Visitor} that creates a formatted
@@ -38,9 +37,6 @@ class ToStringVisitor implements RouterFunctions.Visitor, RequestPredicates.Visi
 
 	private int indent = 0;
 
-	@Nullable
-	private String infix;
-
 
 	// RouterFunctions.Visitor
 
@@ -96,37 +92,36 @@ public void method(Set<HttpMethod> methods) {
 		else {
 			this.builder.append(methods);
 		}
-		infix();
 	}
 
 	@Override
 	public void path(String pattern) {
 		this.builder.append(pattern);
-		infix();
 	}
 
 	@Override
 	public void pathExtension(String extension) {
 		this.builder.append(String.format("*.%s", extension));
-		infix();
 	}
 
 	@Override
 	public void header(String name, String value) {
 		this.builder.append(String.format("%s: %s", name, value));
-		infix();
 	}
 
 	@Override
 	public void queryParam(String name, String value) {
 		this.builder.append(String.format("?%s == %s", name, value));
-		infix();
 	}
 
 	@Override
 	public void startAnd() {
 		this.builder.append('(');
-		this.infix = "&&";
+	}
+
+	@Override
+	public void and() {
+		this.builder.append(" && ");
 	}
 
 	@Override
@@ -137,7 +132,12 @@ public void endAnd() {
 	@Override
 	public void startOr() {
 		this.builder.append('(');
-		this.infix = "||";
+	}
+
+	@Override
+	public void or() {
+		this.builder.append(" || ");
+
 	}
 
 	@Override
@@ -148,7 +148,6 @@ public void endOr() {
 	@Override
 	public void startNegate() {
 		this.builder.append("!(");
-
 	}
 
 	@Override
@@ -161,16 +160,6 @@ public void unknown(RequestPredicate predicate) {
 		this.builder.append(predicate);
 	}
 
-	private void infix() {
-		if (this.infix != null) {
-			this.builder.append(' ');
-			this.builder.append(this.infix);
-			this.builder.append(' ');
-			this.infix = null;
-		}
-	}
-
-
 	@Override
 	public String toString() {
 		String result = this.builder.toString();

spring-webflux/src/test/java/org/springframework/web/reactive/function/server/ToStringVisitorTests.java

@@ -23,8 +23,15 @@
 import org.springframework.http.MediaType;
 
 import static org.junit.Assert.*;
-import static org.springframework.web.reactive.function.server.RequestPredicates.*;
-import static org.springframework.web.reactive.function.server.RouterFunctions.*;
+import static org.springframework.web.reactive.function.server.RequestPredicates.GET;
+import static org.springframework.web.reactive.function.server.RequestPredicates.accept;
+import static org.springframework.web.reactive.function.server.RequestPredicates.contentType;
+import static org.springframework.web.reactive.function.server.RequestPredicates.method;
+import static org.springframework.web.reactive.function.server.RequestPredicates.methods;
+import static org.springframework.web.reactive.function.server.RequestPredicates.path;
+import static org.springframework.web.reactive.function.server.RequestPredicates.pathExtension;
+import static org.springframework.web.reactive.function.server.RequestPredicates.queryParam;
+import static org.springframework.web.reactive.function.server.RouterFunctions.route;
 
 /**
  * @author Arjen Poutsma
@@ -75,6 +82,11 @@ public void predicates() {
 		testPredicate(method(HttpMethod.GET).or(path("/foo")), "(GET || /foo)");
 
 		testPredicate(method(HttpMethod.GET).negate(), "!(GET)");
+
+		testPredicate(GET("/foo")
+				.or(contentType(MediaType.TEXT_PLAIN))
+				.and(accept(MediaType.APPLICATION_JSON).negate()),
+				"(((GET && /foo) || Content-Type: text/plain) && !(Accept: application/json))");
 	}
 
 	private void testPredicate(RequestPredicate predicate, String expected) {