These changes support arbitrary combinations of input + plain types
within a schema. Handling plain types at the property level was not
sufficient to support such combinations. Reifying these types
required updating quite a bit of code. This is likely to have caused
some temporary complications, but should eventually lead to
substantial simplification in the SDK and program code generators.
With the new design, input and optional types are explicit in the schema
type system. Optionals will only appear at the outermost level of a type
(i.e. Input<Optional<>>, Array<Optional<>>, etc. will not occur). In
addition to explicit input types, each object type now has a "plain"
shape and an "input" shape. The former uses only plain types; the latter
uses input shapes wherever a plain type is not specified. Plain types
are indicated in the schema by setting the "plain" property of a type spec
to true.
The PCL binder has supported resource options for some time, but these
options haven't been used or processed by the various code generators.
These options--particularly the parent and provider options0--are
critical for import codegen. These changes implement the basic set of
options, and add a note about fleshing out the rest as necessary.
One component of these changes is a new rewriter that rewrites property
references into property paths that are understood by the Pulumi engine.
This rewriter is used to preprocess the contents of the `ignoreChanges`
resource option.
These changes also hack around a weakness in the HCL2 type system:
In Go, references to resources should be typed as `hcl2.ResourceType`.
Unfortunately, this breaks the existing collection semantics associated
with resources. Because of this, the Go code generator does not have
enough information to know that it should generate a `[]pulumi.Resource`
for lists of resources. These changes hack around that limitation using
a Go-specific opaque type and some hardcoded comparisons in
`argumentTypeName`.
Fixes#4923.
