Non-string input variables taken from the environment initially need to
be parsed and stored as string, since there is no type associated type
information. Make sure these are correctly handled when validated during
apply.
* lang: stabilise ephemeral values experiment
Stabilise the ephemeral values experiment and ephemeralasnull
experimental function.
* simplify handling of apply time input vars
As the final step in stabilising the ephemeral values experiment, we can
remove the separate code path for handling input variables supplied via
-var and -var-file during apply.
The intent here is conveyed in the tests: when applying a saved plan,
all ephemeral variables set in the plan (the "apply-time
variables"), must be set, and no others.
As per the TODO copied from the prototype, there is some more work to be
done here in making the handling of undeclared variables during apply as
sophisticated as that during plan, emitting helpful warnings (for
example) when input variables are supplied unnecessarily via environment
variables.
* experiments: officially conclude EV experiment
---------
Co-authored-by: Radek Simko <radek.simko@gmail.com>
