What is the difference between

TaskOutputs.cacheIf

and

TaskOutputs.upToDateWhen

? Their descriptions from the docs seem to be using different words to say almost the same thing:

cacheIf

... Cache the results of the task only if the given spec is satisfied.

upToDateWhen

... Adds a predicate to determine whether previous outputs of this task can be reused.

What is the distinction between "cached" and "reused"? More concretely: If one has a task that looks at state that isn't in the file system — that is, the output of the depends on more than just the declared

TaskInputs

and so seems non-deterministic if only the

TaskInputs

are taken into account — then which is the correct one to use to ensure that Gradle knows that this task needs to be re-run if any tasks that depend on its output have been requested?

cacheIf

is specific to the build cache, so disabling caching could still reuse state local to your machine (in the

build/

dir).

upToDateWhen

is what determines if the task needs to re-run (when there is local or cached state that could be reused otherwise) But you'll probably want to somehow declare that other source in

TaskInputs

.

Thanks. To make sure I understand: •

upToDateWhen{ false }

— output will never be reused •

cacheIf{ false }

— output may be reused (but if it is, it won't be via the build cache) Is that right?