Previously we were incorrectly passing down the original forEachCtx down
to nested child blocks for recursive expansion. Instead, we must use the
iteration-specific constructed EvalContext, which then allows any nested
dynamic blocks to use the parent's iterator variable in their for_each or
labels expressions, and thus unpack nested data structures into
corresponding nested block structures:
dynamic "parent" {
for_each = [["a", "b"], []]
content {
dynamic "child" {
for_each = parent.value
content {}
}
}
}
This extension allows an application to support dynamic generation of
child blocks based on expressions in certain contexts. This is done using
a new block type called "dynamic", which contains an iteration value
(which must be a collection) and a specification of how to construct a
child block for each element of that collection.
