Change the name of a project included by includeFlat

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1

I want to change the name of a project included by includeFlat:

includeFlat("project1")
project(":project1").name = "p1"

while gradle :p1:build will create building files under a new directory named p1 along with the directory project1, is this normal or is this a bug??

The following one, using include instead, will work as expected.

include "project2"
project(":project2").projectDir = new File("/xxx/yyy/cccc")
project(":project2").name = "p2"