Help SpotlessTask to handle a removed directory.

[nedtwigg]

@bigdaz in a local build with Gradle 6.4.1, I was getting this error:

Caused by: java.nio.file.DirectoryNotEmptyException: C:\Users\ntwigg\Documents\dev\test\build\spotless\spotlessJava\...

so I added special handling for directories. I was a little surprised, I figured that Gradle would pass removed subfolders and such so that you could always just do Files.deleteIfExists().

Unfortunately, I wasn't able to recreate in an integration test. It's surprising, because I had a very simple one that recreated the DirectoryNotEmptyException every single time, but it never triggered the error when running via testkit:

plugins {
    id 'java'
    id 'com.diffplug.gradle.spotless'
}

def generatedDir = new File(project.buildDir, "generated/src/constants/java")
def outputFile = new File(generatedDir, "project/Version.java")
outputFile.getParentFile().mkdirs()
outputFile.setText("package blah; public class Version {}");

sourceSets.main {
    java.srcDir(generatedDir)
}

spotless {
    java {
        targetExclude 'build/**' // comment and uncomment to generate DirectoryNotEmptyException
        googleJavaFormat()
    }
}

Regardless, this small change fixes it and seems harmless. Does this smell right to you?

[bigdaz]

Good catch @nedtwigg and my bad. I can see how this would happen if you removed a source directory that contained files that had previously produced output.

When a source directory has been removed, it's probably fine to recursively delete the output. But we should revisit this mechanism when we move to the improved InputChanges API. I'm hoping to find some time to work on Spotless v5.0 soon.

[nedtwigg]

Released in plugin-gradle 4.1.0.