Characterizing and Detecting Bugs in WeChat Mini-Programs

Built on the WeChat social platform, WeChat Mini-Programs are widely used by more than 400 million users every day. Consequently, the reliability of Mini-Programs is particularly crucial. However, WeChat Mini-Programs suffer from various bugs related to execution environment, lifecycle management, asynchronous mechanism, etc. These bugs have seriously affected users' experience and caused serious impacts.

We conduct the first empirical study on 83 WeChat Mini-Program bugs, and perform an in-depth analysis of their root causes, impacts and fixes. From this study, we obtain many interesting findings that can open up new research directions for combating WeChat Mini-Program bugs. Based on the bug patterns found in our study, we further develop WeDetector to detect WeChat Mini-Program bugs.

Bug patterns

Our empirical study on WeBugs has revealed several potential patterns to detect WeBugs. Among them, we summarize three common bug patterns, i.e., incorrect invocations platform-dependent APIs, incomplete layout adaptation to anomalous screens, and improper handling of return data in invoking asynchronous APIs.

Pattern 1. Incorrect invocations of platform-dependent APIs.

Some APIs in the Mini-Program framework are OS-specific. Invoking these platform-dependent APIs without considering different OS can introduce WeBugs. Therefore, developers should determine target operating system before using these APIs. We summarize four kinds of platform-dependent APIs in this table.

Pattern 2. Incomplete layout adaptation to anomalous screens.

Although the layout of Mini-Programs is self-adaptive, there are also three abnormal rendering bugs. These bugs arise in specific devices due to their anomalous screens. For some devices, e.g., Figure 3a, all their screen can be used to render applications. However, for some devices, e.g., Figure 3b, parts of their screen are occupied by some components, e.g, camera. Thus, rendering applications on the restricted areas can cause abnormal displays.

Pattern 3. Improper handling of return data in invoking asynchronous APIs.

In the WeChat Mini-Program framework, most APIs are used in an asynchronous way. The success and fail callbacks are defined to handle the return data for successful or failed invocations. However, the type or data structure for the return data may vary. If developers are unaware of their differences, WeBugs can occur. Here shows such an example. Function getList calls the function req (Line 3) to send a request. If the request fails, it triggers the fail callback function (Line 17), and returns a boolean data false. Since function getList does not check whether it is a valid value (e.g., Line 4), and operations on a boolean data false can cause a TypeError.

Getting Started

WeDetector - WeChat Mini-Program Bugs Detector

Development environment

• Windows 10

• Node.js v_12.18.3

• Java v_16

• Babel v_6.26.0

npm install -g babel-cli@6.26.0

• TAJS
  You should download the jar files from http://www.brics.dk/TAJS/dist/. And place it under the folder: dist/tajs-all.jar

Testing WeChat Mini-Programs

Before running code, you should put projects into folder benchmarks.

node analyze.js

Publication

If you are interested in our work, you can find more details in our paper listed below. If you use our dateset and tool, please cite our paper.

Characterizing and Detecting Bugs in WeChat Mini-Programs [PDF]

44th IEEE/ACM International Conference on Software Engineering (ICSE'22)