Gradle's Property was never really intended to support null values, so this is kind of a bug. In Gradle 9, this becomes an error. This prevents users from using the plugin with Gradle 9 in cases where the affected configuration is used.

Property#set discards the set value when it receives null. However, this might be technically breaking in some edge cases. I can't think of a good example, but I also can't rule it out. Yet, this is a fix that justifies potential minor breakage.

This was originally pointed out by @NielsDoucet in #21957 (comment) (where a bit more context can be found).

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