Fix double encoding in DefaultApiVersionInserter

Ensure that the DefaultApiVersionInserter does not re-encode existing parts
of the input URI by using the 'encoded' flag in UriComponentsBuilder.

This prevents percent-encoded characters (like %20) from being incorrectly
double-encoded to %2520 during the version insertion process.

See gh-36097

Signed-off-by: Nabil Fawwaz Elqayyim <master@nabilfawwaz.com>

spring-web/src/main/java/org/springframework/web/client/DefaultApiVersionInserter.java

@@ -33,6 +33,7 @@ import org.springframework.web.util.UriComponentsBuilder;
  * Default implementation of {@link ApiVersionInserter}.
  *
  * @author Rossen Stoyanchev
+ * @author Nabil Fawwaz Elqayyim
  * @since 7.0
  * @see DefaultApiVersionInserterBuilder
  */
@@ -81,7 +82,7 @@ final class DefaultApiVersionInserter implements ApiVersionInserter {
 			builder.replacePath(null);
 			pathSegments.forEach(builder::pathSegment);
 		}
-		return builder.build().toUri();
+		return builder.build(true).toUri();
 	}
 
 	private void assertPathSegmentIndex(Integer index, int pathSegmentsSize, URI uri) {

spring-web/src/test/java/org/springframework/web/client/DefaultApiVersionInsertersTests.java

@@ -0,0 +1,52 @@
+/*
+ * Copyright 2002-present 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.web.client;
+
+import java.net.URI;
+
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Unit tests for {@link DefaultApiVersionInserter}.
+ *
+ * @author Nabil Fawwaz Elqayyim
+ */
+class DefaultApiVersionInsertersTests {
+
+	@Test
+	void insertVersionPreservesExistingEncoding() {
+		URI uri = URI.create("http://localhost/test?foo=%20");
+		DefaultApiVersionInserter inserter = (DefaultApiVersionInserter) ApiVersionInserter.usePathSegment(0);
+
+		URI result = inserter.insertVersion("1", uri);
+
+		assertThat(result.toString()).isEqualTo("http://localhost/1/test?foo=%20");
+	}
+
+	@Test
+	void insertVersionAsQueryParamPreservesEncoding() {
+		URI uri = URI.create("http://localhost/test?foo=%20");
+		DefaultApiVersionInserter inserter = (DefaultApiVersionInserter) ApiVersionInserter.useQueryParam("v");
+
+		URI result = inserter.insertVersion("1", uri);
+
+		assertThat(result.toString()).isEqualTo("http://localhost/test?foo=%20&v=1");
+	}
+
+}