Prior to v0.12 Terraform was liberal about these and allowed them to
mismatch, but now it's important to get this right so that resources
and resource instances can be used directly as object values, and so
we'll fix up any sloppy existing references so things keep working as
expected.
This is particularly important for the pattern of using count to create
conditional resources, since previously the "true" case would create one
instance and Terraform would accept an unindexed reference to that.
The reference syntax is not significantly changed, but there are some
minor additional restrictions on identifiers in HCL2 and as a special case
we need to rewrite references to data.terraform_remote_state .
Along with those mandatory upgrades, we will also switch references to
using normal index syntax where it's safe to do so, as part of
de-emphasizing the old strange integer attribute syntax (like foo.0.bar).
Previously we were erroneously moving these out of their original block
into the surrounding body. Now we'll make sure to collect up any remaining
ad-hoc comments inside a nested block body before closing it.
Early on it looked like we wouldn't need to distinguish these since we
were only analyzing for provider types, but we're now leaning directly
on the resource addresses later on and so we need to make sure we produce
valid ones when data resources are present.
Users discovered that they could exploit some missing validation in
Terraform v0.11 and prior to treat block types as if they were attributes
and assign dynamic expressions to them, with some significant caveats and
gotchas resulting from the fact that this was never intended to work.
However, since such patterns are in use in the wild we'll convert them
to a dynamic block during upgrade. With only static analysis we must
unfortunately generate a very conservative, ugly dynamic block with
every possible argument set. Users ought to then clean up the generated
configuration after confirming which arguments are actually required.
We're using break elsewhere in here so it was weird to have a small set
of situations that return instead, which could then cause confusion for
future maintenance if a reader doesn't notice that control doesn't always
leave the outer switch statement.
If lookup is being used with only two arguments then it is equivalent to
index syntax and more readable that way, so we'll replace it.
Ideally we'd do similarly for element(...) here but sadly we cannot
because we can't prove in static analysis that the user is not relying
on the modulo wraparound behavior of that function.
We now have native language features for declaring tuples and objects,
which are the idiomatic way to construct sequence and mapping values that
can then be converted to list, set, and map types as needed.
In the old world, lists and maps could be created either using functions
in HIL or list/object constructs in HCL. Here we ensure that in the HCL
case we'll apply any required expression transformations to the individual
items within HCL's compound constructs.
Previously we were using the line count difference between the start of
one item and the next to decide whether to insert a blank line between
two items, but that is incorrect for multi-line items.
Instead, we'll now count the difference from the final line of the
previous item to the first line of the next, as best we can with the
limited position info recorded by the HCL1 parser.
The old parser was forgiving in allowing the use of block syntax where a
map attribute was expected, but the new parser is not (in order to allow
for dynamic map keys, for expressions, etc) and so the upgrade tool must
fix these to use attribute syntax.
The main area of interest in upgrading is dealing with special cases for
individual block items, so this generalization allows us to use the same
overall body-processing logic for everything but to specialize just how
individual items are dealt with, which we match by their names as given
in the original input source code.
This involved some refactoring of how block bodies are migrated, which
still needs some additional work to deal with meta-arguments but is now
at least partially generalized to support both resource and provider
blocks.
Any state modifying functions can only be run once during the plan-apply
cycle. When regenerating the Diff during ApplyResourceChange, strip out
all StateFunc and CustomizeDiff functions from the schema.
Thew NewExtra diff field was where config data that was modified by a
StateFunc was stored, and needs to be maintained between plan and apply.
During PlanResourceChange, store any NewExtra data from the Diff in the
PlannedPrivate data, and re-insert the NewExtra data into the Diff
generated during ApplyResourceChange.
Variables values are marshalled with an explicit type of
cty.DynamicPseudoType, but were being decoded using `Implied Type` to
try and guess the type. This was causing errors because `Implied Type`
does not expect to find a late-bound value.
Errors were being ignore with the intention that they would be caught
later in validation, but it turns out we nee dto catch those earlier.
The legacy schemas also allowed providers to set and empty string for a
bool value, which we need to handle here, since it's not being handled
from user input like a normal config value.
If an instance object in state has an earlier schema version number then
it is likely that the schema we're holding won't be able to decode the
raw data that is stored. Instead, we must ask the provider to upgrade it
for us first, which might also include translating it from flatmap form
if it was last updated with a Terraform version earlier than v0.12.
This ends up being a "seam" between our use of int64 for schema versions
in the providers package and uint64 everywhere else. We intend to
standardize on int64 everywhere eventually, but for now this remains
consistent with existing usage in each layer to keep the type conversion
noise contained here and avoid mass-updates to other Terraform components
at this time.
This also includes a minor change to the test helpers for the
backend/local package, which were inexplicably setting a SchemaVersion of
1 on the basic test state but setting the mock schema version to zero,
creating an invalid situation where the state would need to be downgraded.
The rest of Terraform is still using uint64 for this in various spots, but
we'll update that gradually later. We use int64 here because that matches
what's used in our protobuf definition, and unsigned integers are not
portable across all of the protobuf target languages anyway.
There's no reason for a negative version, so by blocking it now we'll
ensure that none creep in.
The more practical short-term motivation for this is that we're still
using uint64 for these internally in some cases and so this restriction
ensures that we won't run into rough edges when converting from int64 to
uint64 at those boundaries until we later fix everything to use int64
consistently.
Add support for the new `force-unlock` API and at the same time improve
performance a bit by reducing the amount of API calls made when using
the remote backend for state storage only.
Previously we were making an invalid assumption in evaluating module call
references (like module.foo) that the module must exist, which is
incorrect for that particular case because it's a reference to a child
module, not to an object within the current module.
However, now that we have the mechanism for static validation of
references, we'll deal with this one there so it can be caught sooner.
That then makes the original assumption valid, though for a different
reason.
This is verified by two new context tests for validation:
- TestContext2Validate_invalidModuleRef
- TestContext2Validate_invalidModuleOutputRef
Martin Atkins