Fix GenericUrl to decode path parts correctly

google-http-client/src/main/java/com/google/api/client/http/GenericUrl.java

@@ -548,7 +548,7 @@ public static List<String> toPathParts(String encodedPath) {
       } else {
         sub = encodedPath.substring(cur);
       }
-      result.add(CharEscapers.decodeUri(sub));
+      result.add(CharEscapers.decode(sub));
       cur = slash + 1;
     }
     return result;

google-http-client/src/main/java/com/google/api/client/util/escape/CharEscapers.java

@@ -15,6 +15,8 @@
 package com.google.api.client.util.escape;
 
 import java.io.UnsupportedEncodingException;
+import java.net.URI;
+import java.net.URISyntaxException;
 import java.net.URLDecoder;
 
 /**
@@ -96,6 +98,32 @@ public static String decodeUri(String uri) {
     }
   }
 
+  /**
+   * Percent-decodes a US-ASCII string into a Unicode string. UTF-8 encoding is used to determine
+   * what characters are represented by any consecutive sequences of the form "%<i>XX</i>".
+   *
+   * <p>
+   * This doesnt replaces each occurrence of '+' with a space, ' '. So this method should not be
+   * used for application/x-www-form-urlencoded strings such as query.
+   * </p>
+   *
+   * @param uri a percent-encoded US-ASCII string
+   * @return a Unicode string
+   */
+  public static String decode(String uri) {
+    if (uri.indexOf('%') > -1) {
+      if (uri.indexOf('+') > -1) {
+        try {
+          return new URI(uri).getPath();
+        } catch (URISyntaxException e) {
+          throw new RuntimeException(e);
+        }
+      }
+      return decodeUri(uri);
+    }
+    return uri;
+  }
+
   /**
    * Escapes the string value so it can be safely included in URI path segments. For details on
    * escaping URIs, see <a href="http://tools.ietf.org/html/rfc3986#section-2.4">RFC 3986 - section

google-http-client/src/test/java/com/google/api/client/http/GenericUrlTest.java

@@ -475,6 +475,8 @@ public void testToPathParts() {
     subtestToPathParts("/path/to/resource", "", "path", "to", "resource");
     subtestToPathParts("/path/to/resource/", "", "path", "to", "resource", "");
     subtestToPathParts("/Go%3D%23%2F%25%26%20?%3Co%3Egle/2nd", "", "Go=#/%& ?<o>gle", "2nd");
+    subtestToPathParts("/path+with+plus/2nd", "", "path+with+plus", "2nd");
+    subtestToPathParts("/path%2Bwith+plus/2nd", "", "path+with+plus", "2nd");
   }
 
   private void subtestToPathParts(String encodedPath, String... expectedDecodedParts) {