Check internal JNI calls for pending exceptions and no-op

[fractalwrench]

Goal

Makes safe all invocations of GetMethodId, GetStaticMethodId, and FindClass within the NDK module. This is achieved by calling ExceptionClear to remove any pending JVM exceptions that could lead to app termination. The return value of all these invocations is checked for NULL, and no-ops if this is the case.

Changeset

• Replaced FindClass with bsg_safe_find_class (and equivalents for GetMethodId/GetStaticMethodId)
• When loading a class, check if there was an exception in the JVM, and if so clear it and return NULL. The following errors can be thrown. As these are not recoverable, Bugsnag should no-op rather than crashing the process:
  • NoSuchMethodError
  • ExceptionInInitializerError
  • OutOfMemoryError
  • ClassFormatError
  • ClassCircularityError
  • NoClassDefFoundError
• Alter all invocations to check the return value for NULL and no-op in this case
• Added inline comments to explain what each JNI call is doing, which should improve readability (this comes from a previous review comment and it seemed an opportune moment)

Testing

Relied on existing test coverage.

Remaining work

The ANR plugin has not been converted to use these safe calls yet as it cannot directly access the methods. There are also several other JNI calls which can throw errors that Bugsnag does not currently handle. Both these will be addressed in separate changesets.

[bugsnagbot]

Android notifier sizes

Format	Size impact of Bugsnag (kB)	Size impact of Bugsnag when Minified (kB)
APK	1461.56	1376.29
arm64_v8a	377.51	291.5
armeabi	357.03	271.01
armeabi_v7a	340.65	250.54
x86	418.45	328.34
x86_64	397.98	311.97

Generated by 🚫 Danger