* hcl2template: err on malformed local/data dep
When introducing the DAG for locals and datasources, we forgot to handle
one limit case: if a dependency for a local or data is malformed, we
didn't check that a vertex was associated to it, leading to the final
DAG being malformed, and the DAG library would crash in this case.
This commit fixes this problem by checking that the dependency does
exist before attempting to add it to the graph as an edge for a vertex,
so that it is reported accurately, and do that Packer doesn't crash.
* error message change
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Co-authored-by: anshul sharma <[email protected]>
Since we introduce the DAG with this series of commits, only on locals
and data sources, we need to make sure that the behaviour is what we
expect.
Therefore, this commit adds a basic test with Packer build, and packer
validate, to evaluate a template with both locals and data sources
depending on one another.
This is rejected with the sequential evaluation methods, as we process
the different types one-by-one, whereas the DAG allows us to mix the
order between the two, while still rejecting circular dependencies (and
doing that before they even get evaluated), and self-references.