Regress AWS-3835

[t0yv0]

No description provided.

[t0yv0]

We're not expecting this here at all... somehow Check decided that the unknown value "04da6b54-80e4-46f7-96ec-b56ff0331ba9" should now be [{}]

[VenelinMartinov]

Should we be passing in unknown for the whole thing? Why do we not pass in a set of unknown instead of an unknown set?

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 60.08%. Comparing base (0e639f6) to head (334f33d).

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1881      +/-   ##
==========================================
+ Coverage   60.06%   60.08%   +0.02%     
==========================================
  Files         327      327              
  Lines       43919    43919              
==========================================
+ Hits        26378    26390      +12     
+ Misses      16050    16038      -12     
  Partials     1491     1491              

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[t0yv0]

// makeTerraformUnknown creates an unknown value with the shape indicated by the given schema.
//
// It is important that we use the TF schema (if available) to decide what shape the unknown value should have:
// e.g. TF does not play nicely with unknown lists, instead expecting a list of unknowns.
func makeTerraformUnknown(tfs shim.Schema) interface{} {

I suspect this is coming from some working around TF blocks (single-, list- and set-nested) that in TF don't naturally receive unknowns, but do in Pulumi, so it's substituting empty plausible values instead of unknown values. It would be interesting to see if modern TF can actually handle unknowns here or if this substitution is necessary, for MakeTerraformInptus to do the right thing in these situations.

This feels entirely undesirable though for Check. Here trying to turn around through TF loses unknown-ness information. That is not what we want. It would make more sense for Check not to swallow unknowns.

[t0yv0]

CC @VenelinMartinov @iwahbe

[t0yv0]

As a side-effect of this the diffs don't look right at all. I wonder if we could fix that while not introducing any more issues to the underlying machinery.