fix(terraform): pass module outputs to other modules

[nikpivkin]

Description

Related issues

• Close bug(terraform): module output values are not passed into the context of other modules #6274

Checklist

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• I've followed the conventions in the PR title.
• I've added tests that prove my fix is effective or that my feature works.
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[fwereade]

FWIW: I think I've had good results from re-evaluating submodules when their inputs change. You can see the approach here (against an old defsec which I currently depend on) – I think it currently evaluates modules-with-outputs one more time than it needs to, but the performance cost doesn't seem excessive and the strategy seems to align well with how the rest of the package works.

The specific test case I've been working against is here; backporting the approach in this PR doesn't appear to address that scenario, but that may be due to other changes since v0.93.1.

(I don't claim any particular expertise here, but I hope this is relevant/helpful. And I'd like to update the tfparse dependency to point at current code, but I can't commit to a timeframe for that.)

[nikpivkin]

Hi @fwereade !

Thanks for the research! I will familiarise myself with your solution and give feedback.

[nikpivkin]

@fwereade Looks great! Do you mind if I open a PR with your changes or maybe you want to do it yourself?

[fwereade]

@nikpivkin thanks! please go ahead and open a PR, I can't promise when I'd get to it myself

FWIW, I think it could use a little improvement: I'm pretty lastInputs/lastOutputs should be replaced with a lastState from ctx.Get("module", name) after setting the outputs (and the DeepEqual check against the same), so that a module with outputs doesn't misinterpret them as new inputs and re-eval; this would also render the extracted GetInputVars redundant

…but I'll leave it to your judgment :)

[nikpivkin]

Closed in favor of #6411