Preconditions.checkState(x != null)

[elharo]

In 0.7.8 it's not quite smart enough to follow this

    public AppEngineWebXmlProjectStageConfiguration build() {
      Preconditions.checkState(sourceDirectory != null, "No source directory supplied");
      Preconditions.checkState(stagingDirectory != null, "No staging directory supplied");

      return new AppEngineWebXmlProjectStageConfiguration(
          this.sourceDirectory,
          this.stagingDirectory,
          this.dockerfile,
          this.enableQuickstart,
          this.disableUpdateCheck,
          this.enableJarSplitting,
          this.jarSplittingExcludes,
          this.compileEncoding,
          this.deleteJsps,
          this.enableJarClasses,
          this.disableJarJsps,
          this.runtime);
    }

That is, in a Builder inner class I'm using Preconditions.checkState (from Guava) instead of Preconditions.checkNotNull because an IllegalStateException is slightly more appropriate here than a NullPointerException. Whatever the exception type, though, the return line can't be reached when sourceDirectory or stagingDirectory are null. However Nullaway thinks these can be reached in that case.

• [X ] If you think you found a bug, please include a code sample that reproduces the problem. A test case that reproduces the issue is preferred. A stack trace alone is ok but may not contain enough context for us to address the issue.

• [ X] Please include the library version number, including the minor and patch version, in the issue text.

[msridhar]

Hi @elharo, thanks for the report! At first glance, I don't think it will easy to catch this one without a special-case hack. We have ways to specify functions that check the nullness of an argument, but nothing yet to inspect boolean arguments more deeply when a function checks their truth. I think adding this kind of support would be low priority as we haven't seen it much before.

You can work around this issue by writing your own version of checkNotNull that throws an IllegalStateException instead, and annotating that method with @Contract("null -> fail") (see docs). I'll leave this issue open in case we do decide to add more specialized support in the future.

[msridhar]

@lazaroclapp we can close this one yes? I think it is fixed in 0.9.8

[lazaroclapp]

I believe we can, this should be a specific case of the support for checkArgument/checkState in #608 🎉 (fixed in NullAway 0.9.8)