AbstractMockHttpServletRequestBuilder#buildRequest is not idempotent

See gh-35493

Signed-off-by: Réda Housni Alaoui <reda-alaoui@hey.com>

spring-test/src/main/java/org/springframework/test/web/servlet/request/AbstractMockHttpServletRequestBuilder.java

@@ -74,6 +74,7 @@ import org.springframework.web.util.UrlPathHelper;
  * @author Arjen Poutsma
  * @author Sam Brannen
  * @author Kamill Sokol
+ * @author Réda Housni Alaoui
  * @since 6.2
  * @param <B> a self reference to the builder type
  */
@@ -854,16 +855,17 @@ public abstract class AbstractMockHttpServletRequestBuilder<B extends AbstractMo
 		request.setContextPath(this.contextPath);
 		request.setServletPath(this.servletPath);
 
-		if ("".equals(this.pathInfo)) {
+		String pathInfoToUse = this.pathInfo;
+		if ("".equals(pathInfoToUse)) {
 			if (!requestUri.startsWith(this.contextPath + this.servletPath)) {
 				throw new IllegalArgumentException(
 						"Invalid servlet path [" + this.servletPath + "] for request URI [" + requestUri + "]");
 			}
 			String extraPath = requestUri.substring(this.contextPath.length() + this.servletPath.length());
-			this.pathInfo = (StringUtils.hasText(extraPath) ?
+			pathInfoToUse = (StringUtils.hasText(extraPath) ?
 					UrlPathHelper.defaultInstance.decodeRequestString(request, extraPath) : null);
 		}
-		request.setPathInfo(this.pathInfo);
+		request.setPathInfo(pathInfoToUse);
 	}
 
 	private void addRequestParams(MockHttpServletRequest request, MultiValueMap<String, String> map) {

spring-test/src/test/java/org/springframework/test/web/servlet/request/AbstractMockHttpServletRequestBuilderTests.java

@@ -31,6 +31,7 @@ import static org.assertj.core.api.Assertions.assertThat;
  * Tests for {@link AbstractMockHttpServletRequestBuilder}
  *
  * @author Stephane Nicoll
+ * @author Réda Housni Alaoui
  */
 class AbstractMockHttpServletRequestBuilderTests {
 
@@ -97,6 +98,14 @@ class AbstractMockHttpServletRequestBuilderTests {
 	}
 
 
+	@Test
+	void pathInfoIsNotMutatedByBuildMethod() {
+		TestRequestBuilder builder = new TestRequestBuilder(HttpMethod.GET).uri("/b");
+		assertThat(buildRequest(builder).getPathInfo()).isEqualTo("/b");
+		builder.uri("/a");
+		assertThat(buildRequest(builder).getPathInfo()).isEqualTo("/a");
+	}
+
 	private MockHttpServletRequest buildRequest(AbstractMockHttpServletRequestBuilder<?> builder) {
 		return builder.buildRequest(this.servletContext);
 	}