API Compatibility Issues

[lilicoding]

Dear developers,

We have recently developed a state-of-the-art static analysis tool for uncovering API compatibility issues in Android apps. Applying this tool to open source apps on F-droid, we have exposed a few instances of compatibility issues and submitting them to development teams for a fix.

For your app, we have found that this project has accessed the following APIs which are available only on an API level higher than the declared minSdkVersion and which are accessed without proper protection. In other words, if those APIs get called at runtime, it will trigger a NoSuchMethodError and thus result in a crash of the running application.

<java.util.Arrays: int[] copyOf(int[],int)>:[9,25]

Note that, because of the nature of the static analysis, we cannot confirm whether the flagged APIs would actually be called at runtime (e.g., unreachable code). However, we still believe that those APIs, which may cause compatibility issues, should not be accessed or at least be accessed with proper protections.

In addition to the aforementioned APIs (i.e., backward-compatibility), which could cause app crashes if accessed, we have also identified that this project has also accessed some APIs that have been removed from the latest public SDK, making the app possibly suffer from forward-compatibility issues.

NONE

We would be very much appreciated if you can acknowledge to us that those reported APIs are indeed problematic for the project’s long-term stability. please let us know if you need any more information relating to this issue report.

[MihaiBalint]

Cool thanks. Can I get a copy of (or a link to) the research results? Also what's the "NONE" thing above? Does it mean that there are no fwd-compatibility issues?

[lilicoding]

Dear Mihai,

Thank you very much for your feedback, which is very useful for improving our research tool.

I have sent our research results to you by email.
In a short, API <java.util.Arrays: int[] copyOf(int[],int)> has been accessed by <ro.mihai.tpt.model.HourlyPlan: int[][] loadPlanTable(ro.mihai.util.BPInputStream)> without protection.

And, "NONE" indeed means that there is no forward-compatibility issue reported by our research tool. We are sorry for that. Next time, we will not report this information if it is not concerned.