Compilation error with ProGuard enabled due to FindBugs annotation `SuppressFBWarnings`

[Whathecode]

Describe the bug
Using ProGuard 7.2.0-beta2 and ObjectBox 3.0.1, I get the following ProGuard warning during compilation:

Warning: io.objectbox.ideasonly.ModelModifier$PropertyModifier: can't find referenced class edu.umd.cs.findbugs.annotations.SuppressFBWarnings

Seemingly the SuppressFBWarnings class on ModelModifier.PropertyModifier can't be found. Since this seems part of a static analysis for FindBugs, I can simply disable the warning using the following proguard rules:

-dontwarn io.objectbox.ideasonly.ModelModifier$PropertyModifier

Basic info (please complete the following information):

• ObjectBox version: 3.0.1
• Reproducibility: always

Expected behavior
For this to work out-of-the-box. Perhaps by including the dontwarn rule in the packaged objectbox-java.pro.

Additional context
I am currently upgrading from ProGuard which is integrated as part of the Android Gradle Plugin 7.1.0-beta1 to the separate Proguard Gradle Plugin in order to see whether the latest version resolves a potential obfuscation bug I am running into. Therefore, I have currently enabled ProGuard on my debug build. Not certain whether this impacts ObjectBox, but figured this might be relevant to mention. Regardless, I just also tested in release, and the same warning shows up.

[greenrobot-team]

Thanks. Your title says compilation error, but the message indicates it is only a warning. Are you sure that warning is the cause of the error? Or does the app actually compile?

Anyhow, yes, we should probably add a dontwarn rule for the SpotBugs annotations.

[greenrobot-team]

@Whathecode Just to make clear, this warning only happens with a separate ProGuard plugin (7.2.0-beta2)? I failed to repro with Android Gradle Plugin 7.1.0-beta1.

As the affected class isn't used anywhere this might be a ProGuard regression...

[greenrobot-team]

Next update will add this rule:

-dontwarn edu.umd.cs.findbugs.annotations

@Whathecode Can you verify if this one also works?

[Whathecode]

I can check, but I doubt it. Afaik the -dontwarn rule needs to specify the class from where the warning originates. It doesn't filter out warnings for missing classes.

[Whathecode]

On top of that, edu.ud.cs.findbugs.annotations is an incomplete class filter. If what is intended is all classes in that namespace you need to append .*, or .** to include deeper namespaces. Note that the only class that triggered a warning for me was the one I listed before.

As expected (stated in the previous message), the rule you suggest does not resolve the warning.

[greenrobot-team]

You are right, mixed up syntax.
So

-dontwarn edu.umd.cs.findbugs.annotations.**

does not work as well? I vaguely remember adding a rule for a referenced class worked as well.

[Whathecode]

Just checked, and that indeed works!

Interesting. That is not clearly documented in the ProGuard documentation.

Wouldn't it still be better to then use the following more specific rule?

-dontwarn edu.umd.cs.findbugs.annotations.SuppressFBWarnings

[greenrobot-team]

Thanks for verifying! Next update will (actually) add the more specific rule:

-dontwarn edu.umd.cs.findbugs.annotations.SuppressFBWarnings

[greenrobot-team]

This is included in the 3.1.0 release.