sourceFiles should ignore empty dirs

[wolfs]

The GenerateProto task only relies on source files, so it should ignore empty directories. Gradle 6.8 introduced the IgnoreEmptyDirectories annotation, which allows declaring that.

In this PR, I add the IgnoreEmptyDirectories annotation to GenerateProto.sourceFiles.

[wolfs]

This PR builds on #531, so it should only contain adding the annotation in the end.

[wolfs]

@ejona86 This is ready for review now. Please take a look.

[ejona86]

so it should ignore empty directories

What is the harm if it doesn't?

[wolfs]

so it should ignore empty directories

What is the harm if it doesn't?

The harm is two fold:

• Right now, the task will be out-of-date when you add an empty directory to the source folder. There will also be a build cache miss if the only difference between the sources is an empty directory somewhere.
• In Gradle 8.0, the task won't skip any more if there are only empty directories in the source folder and no actual files. That is because the behaviour for skipping when empty and up-to-date checking will be more consistent.

[ejona86]

Thanks! I included those notes in the commit message.

[wolfs]

@ejona86 Awesome, thank you for the quick turnaround! Any idea when you have time to publish a release of the plugin including this changes?

[ejona86]

I was going to give some time to see if #523 can make it into the release. I was expecting to do the release early next week.