The manual of the augment task states that it's supposed to throw a `BuildException` if the referenced id value isn't known. I admit that the bugzilla is more about the id attribute not being specified whereas the manual seems to talk about the value of id being unknown reference, but I think the issue itself can be considered valid.
The referenced bugzilla issue shows that it throws an `IllegalStateException`. That exception then does indeed get thrown as a BuildException but the `reason` that gets reported to the build listeners is the original cause (in this case the `IllegalStateException`).
The commit here is trivial and it throws the `BuildException` from the `augment` task when either `id` isn't specified or it points to an unknown reference. However, given that it appears that this task has always been in this manner, I wanted to make sure there isn't any specific reason of its current implementation.
There's already tests for this task which pass both with and without this change