Investigate the need to re-plan the resource outputs in Update if a resource is going to be replaced

[VenelinMartinov]

What happened?

During the work on detailed diff we discovered that we are not correctly marking fully computed properties for re-computation when a resource is replaced: #2660

A similar issue might affect Update - it does not call Plan twice, so it likely also fails to correctly mark computed properties as Unknown if the resource is going to get replaced. This likely has an effect on the correctness of the preview when previewing changes, as the engine does not find out that certain inputs to resources might change.

The other possibility is that the engine is conservative about this and always marks a dependent resource for replacement. In that case perhaps this is fine?

Example

A similar setup to #2660 but what would happen if a secondary resource uses the fully computed ID property of the primary resource as an input. The secondary resource should also get marked for replacement.

If we transition from: properties: {} to properties: {key: "value"} for the PF schema

rschema.Schema{
	Attributes: map[string]rschema.Attribute{
		"key": rschema.StringAttribute{
			Optional:      true,
			PlanModifiers: []planmodifier.String{stringplanmodifier.RequiresReplace()},
		},
		"id": rschema.StringAttribute{
			Computed: true,
			PlanModifiers: []planmodifier.String{
				stringplanmodifier.UseStateForUnknown(),
			},
		},
	},
}

We get:

	pulumiOut: `Previewing update (test):
  pulumi:pulumi:Stack: (same)
    [urn=urn:pulumi:test::project::pulumi:pulumi:Stack::project-test]
    +-testprovider:index/test:Test: (replace)
        [id=test-id]
        [urn=urn:pulumi:test::project::testprovider:index/test:Test::p]
      + key: "value"
Resources:
    +-1 to replace
    1 unchanged

versus

  # testprovider_test.res must be replaced
+/- resource "testprovider_test" "res" {
      ~ id  = "test-id" -> (known after apply)
      + key = "value" # forces replacement
    }

Output of pulumi about

.

Additional context

No response

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