Spotless bug reproduction repository

This repo is a SSCCE of a potential bug with the Spotless formatting tool for Gradle.

Current behavior:

If I run spotlessApply -PspotlessIdeHook=/path/to/my/file more than once, undoing the formatting changes after the first invocation, subsequent invocations won't apply changes to the file.

Expected behavior:

Spotless should be consistent and idempotent, so I should be able to run it as many times as I want and get the same output each time.

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To reproduce the issue:

1. Clone the repository.
2. Ensure App.java does not end with a newline.
3. Format the file using the IDE hook. format-app-file is a helper script that does this for you.
4. Ensure the task output contains IS DIRTY and that the file now ends with a newline.
5. Remove the newline.
6. Without running ./gradlew clean, re-run ./format-app-file.
7. Observe that the file does not end with a newline, and that the task output does not show IS DIRTY.

Notes:

• Running ./gradlew clean will reset the Gradle state to a point where the IDE hook will work again, but only on its first invocation.
• Running ./gradlew spotlessApply without the IDE hook seems to always work, regardless of the state of the cache. This will not bust the cache though.