In 3ea1592 the plan rendering was refactored to add an extra indirection
of producing a display-oriented plan object first and then rendering from
that object.
There was a logic error while adapting the existing plan rendering code
to use the new display-oriented object: the core InstanceDiff object sets
the "Destroy" flag (a boolean) for both DiffDestroy and DiffDestroyCreate,
and so this code previously checked r.Destroy to recognize the
"destroy-create" case. This was incorrectly adapted to a check for the
display action being DiffDestroy, when it should actually have been
DiffDestroyCreate.
The effect of this bug was to cause the "(forces new resource)"
annotations to not be displayed on attributes, though the resource-level
information still correctly reflected that a new resource was required.
This fix restores the attribute-level annotations.
Previously we just assumed the reader was familiar with the idea of a
graph but didn't explain it.
Since graphs are an implementation detail of Terraform, rather than
essential information needed for new users, this revises the introduction
text to talk only about _dependencies_, which we assume the user is
familiar with as a more practical concept.
Additionally, Paul Hinze did a great talk on how Terraform uses graphs
at HashiConf 2016 which is good additional content for our existing
"Graph Internals" page, which includes a concise explanation of the
basics of graph theory.
Add an ImportStateIdFunc field to the ImportState testing functionality.
This will allow for more powerful generation of complex import state IDs
that can't be accomplished by ImportStateId or ImportStateIdPrefix
themselves.