Fix ProGuard optimizing of error deserialization code, in particular @JsonCreator annotated constructor.

Karl Rieb · Karl Rieb · commit e2229a87cd4b · 2016-05-06T16:32:13.000-07:00
See bug report here: https://www.dropboxforum.com/hc/en-us/community/posts/205611143-BadResponseException-Bad-JSON Fixes T94429
diff --git a/ChangeLog.txt b/ChangeLog.txt
@@ -1,3 +1,7 @@
+---------------------------------------------
+2.0.3
+- Fix Bad JSON error on ProGuard optimized APKs when deserializing error responses.
+
 ---------------------------------------------
 2.0.2 (2016-04-28)
 - Update to latest API specs:
diff --git a/examples/android/build.gradle b/examples/android/build.gradle
@@ -23,7 +23,7 @@ apply plugin: 'com.android.application'
 
 android {
     compileSdkVersion 23
-    buildToolsVersion "23.0.2"
+    buildToolsVersion "23.0.3"
 
     defaultConfig {
         applicationId "com.dropbox.core.examples.android"
@@ -34,12 +34,14 @@ android {
     }
     buildTypes {
         release {
-            minifyEnabled false
+            minifyEnabled true
+            shrinkResources true
             proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
         }
         debug {
             // to debug ProGuard rules
             minifyEnabled false
+            shrinkResources false
             proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
         }
     }
@@ -57,8 +59,8 @@ dependencies {
     compile 'com.android.support:appcompat-v7:23.1.1'
     compile 'com.android.support:design:23.1.1'
     compile 'com.android.support:recyclerview-v7:23.1.1'
-    compile 'com.fasterxml.jackson.core:jackson-core:2.5.4'
-    compile 'com.fasterxml.jackson.core:jackson-annotations:2.5.4'
+    compile 'com.fasterxml.jackson.core:jackson-core:2.7.1'
+    compile 'com.fasterxml.jackson.core:jackson-annotations:2.7.1'
     compile 'com.squareup.picasso:picasso:2.5.2'
     compile 'com.squareup.okhttp:okhttp:2.4.0'
 }
diff --git a/src/main/java/com/dropbox/core/DbxRequestUtil.java b/src/main/java/com/dropbox/core/DbxRequestUtil.java
@@ -272,6 +272,13 @@ public static ErrorWrapper fromResponse(Type errType, HttpRequestor.Response res
                 );
             ApiErrorResponse<?> apiResponse = JSON.readValue(response.getBody(), type);
 
+            // ProGuard/Dex hack: prevent ProGuard/Dex from optimizing away our @JsonCreator
+            // constructor. We add this code here instead of updating our rules to allow developers
+            // to easily fix their broken apps by updating the SDK version (see T94429).
+            if (errType == null) {
+                new ApiErrorResponse<Object>("impossible", new LocalizedText("impossible", "en_US"));
+            }
+
             return new ErrorWrapper(apiResponse.getError(), requestId, apiResponse.getUserMessage());
         }
 
