The DestroyEdgeTransformer cannot determine ordering from the graph when
the destroyers are from orphaned resources, because there are no
references to resolve. The new stored Dependencies provides what we need
to connect the instances in this case.
We also add the StateDependencies method directly in the
GraphNodeResourceInstance interface, since all instances already
implement this, and we don't need another optional interface to check.
The old code in DestroyEdgeTransformer may no longer be needed in the
long run, but that can be determined separately, since too many of the
tests start with an incomplete state and rely on the Dependencies being
determined from the configuration alone.
Refresh should load any new dependencies found because of configuration
or state changes, but retain any dependencies already in the state.
Orphaned resources would not be in config, but we do not want to lose
the destroy ordering for the later apply.
Make use of the new Dependencies field in the instance state.
The inter-instance dependencies will be determined from the complete
reference graph, so that absolute addresses can be stored, rather than
just references within a module. The Dependencies are added to the node
in the same manner as state, i.e. via an "attacher" interface and
transformer. This is because dependencies are calculated from the graph
itself, and not from the config.
We need to be able to reference all possible dependencies for ordering
when the configuration is no longer present, which means that absolute
addresses must be used. Since this is only to recreate the proper
ordering for instance destruction, only resources addresses need to be
listed rather than individual instance addresses.
If a resource is only destroying instances, there is no reason to
prepare the state and we can remove the Resource (prepare state) nodes.
They normally have pose no issue, but if the instances are being
destroyed along with their dependencies, the resource node may fail to
evaluate due to the missing dependencies (since destroy happens in the
reverse order).
These failures were previously blocked by there being a cycle when the
destroy nodes were directly attached to the resource nodes.
Destroy nodes do not need to be connected to the resource (prepare
state) node when adding them to the graph. Destroy nodes already have a
complete state in the graph (which is being destroyed), any references
will be added in the ReferenceTransformer, and the proper
connection to the create node will be added in the
DestroyEdgeTransformer.
Under normal circumstances this makes no difference, as create and
destroy nodes always have an dependency, so having the prepare state
handled before both only linearizes the operation slightly in the
normal destroy-then-create scenario.
However if there is a dependency on a resource being replaced in another
module, there will be a dependency between the destroy nodes in each
module (to complete the destroy ordering), while the resource node will
depend on the variable->output->resource chain. If both the destroy and
create nodes depend on the resource node, there will be a cycle.
The CBDEdgeTransformer tests worked on fake data structures, with a
synthetic graph, and configs that didn't match. Update them to generate
a more complete graph, with real node implementations, from real
configs.
The output graph is filtered down to instances, and the results still
functionally match the original expected test results, with some minor
additions due to using the real implementation.
When looking for dependencies to fix when handling
create_before_destroy, we need to look past more than one edge, as
dependencies may appear transitively through outputs and variables. Use
Descendants rather than UpEdges.
We have the full graph to use for the CBD transformation, so there's no
longer any need to create a temporary graph, which may differ from the
original.
During the 0.12 work we intended to move all of the variable value
collection logic into the UI layer (command package and backend packages)
and present them all together as a unified data structure to Terraform
Core. However, we didn't quite succeed because the interactive prompts
for unset required variables were still being handled _after_ calling
into Terraform Core.
Here we complete that earlier work by moving the interactive prompts for
variables out into the UI layer too, thus allowing us to handle final
validation of the variables all together in one place and do so in the UI
layer where we have the most context still available about where all of
these values are coming from.
This allows us to fix a problem where previously disabling input with
-input=false on the command line could cause Terraform Core to receive an
incomplete set of variable values, and fail with a bad error message.
As a consequence of this refactoring, the scope of terraform.Context.Input
is now reduced to only gathering provider configuration arguments. Ideally
that too would move into the UI layer somehow in a future commit, but
that's a problem for another day.
We previously deferred this to Validate, but all of our operations require
a valid set of variables and so checking this up front makes it more
obvious when a call into Terraform Core from the CLI layer isn't
populating variables correctly, instead of having it fail downstream
somewhere.
It's the caller's responsibility to ensure that it has collected values
for all of the variables in some way before calling NewContext, because
in the main case driven by the CLI there are many different places that
variable values can be collected from and so handling the main user-facing
validation in the CLI allows us to return better error messages that take
into account which way a variable is (or is not) being set.
Previously we were using the experimental HCL 2 repository, but now we'll
shift over to the v2 import path within the main HCL repository as part of
actually releasing HCL 2.0 as stable.
This is a mechanical search/replace to the new import paths. It also
switches to the v2.0.0 release of HCL, which includes some new code that
Terraform didn't previously have but should not change any behavior that
matters for Terraform's purposes.
For the moment the experimental HCL2 repository is still an indirect
dependency via terraform-config-inspect, so it remains in our go.sum and
vendor directories for the moment. Because terraform-config-inspect uses
a much smaller subset of the HCL2 functionality, this does still manage
to prune the vendor directory a little. A subsequent release of
terraform-config-inspect should allow us to completely remove that old
repository in a future commit.
The old logic for `depends_on` was to short-circuit evaluation of the
data source, but that prevented a plan and state from being recorded.
Use the (currently unused) ForcePlanRead to ensure that the plan is
recorded when the config contains `depends_on`.
This does not fix the fact that depends on does not work with data
sources, and will still produce a perpetual diff. This is only to fix
evaluation errors when an indexed data source is evaluated during
refresh.
* command/import: properly use `-provider` supplied on the command line
The import command now attaches the provider configuration in the resource
instance, if set. That config is attached to the NodeAbstractResource
during the import graph building. This prevents errors when the implied
provider is not actually in the configuration at all, which may happen
when a configuration is using the `-beta` version of a provider (and
only that `-beta` version).
* command/import: fix variable reassignment and update docs
Fixes#22564
Now that the most common cause of unknowns (invalid resource indexes) is
caught earlier, we can validate that the final apply config is wholly
known before attempting to apply it. This ensures that we're applying
the configuration we intend, and not silently dropping values.
Always return the entire resource object from
evaluationStateData.GetResource, rather than parsing the references for
individual instances. This allows for later evaluation of resource
indexes so we can return errors when they don't exist, and prevent
errors when short-circuiting around invalid indexes in conditionals.
In order to allow lazy evaluation of resource indexes, we can't index
resources immediately via GetResourceInstance. Change the evaluation to
always return whole Resources via GetResource, and index individual
instances during expression evaluation.
This will allow us to always check for invalid index errors rather than
returning an unknown value and ignoring it during apply.
The documentation for the -target option warns that it's intended for
exceptional circumstances only and not for routine use, but that's not a
very prominent location for that warning and so some users miss it.
Here we make the warning more prominent by including it directly in the
Terraform output when -target is in use. We first warn during planning
that the plan might be incomplete, and then warn again after apply
concludes and direct the user to run "terraform plan" to make sure that
there are no further changes outstanding. The latter message is intended
to reinforce that -target should only be a one-off operation and that you
should always run without it soon after to ensure that the workspace is
left in a consistent, converged state.
This interface is meant to replace the following ones (in use by some providers):
- httpclient.UserAgentString() (e.g. AzureRM, Google)
- terraform.UserAgentString (e.g. OpenStack, ProfitBricks)
- terraform.VersionString (e.g. AWS, AzureStack, DigitalOcean, Kubernetes)
This also proposes the initial UA string to be set to
HashiCorp Terraform/X.Y.Z (+https://www.terraform.io)
This also fixes a few things with resource for_each:
It makes validation more like validation for count.
It makes sure the index is stored in the state properly.
Remove reflect.DeepEqual from path comparisons to get reliable results.
The equality issues were only noticed going the grpc interface, so add a
corresponding test to the test provider.
Fix for a crash during terraform plan: If there is a multi-instance
resource (count > 1) where one of the instances was deleted in the
deployment but was still present in the terraform state,
getResourceInstancesAll crashed.
Check not only for rs.Instances[key] to exist, but also to have a
valid Current pointer.
This also includes a previously-missing test that verifies the behavior
described here, implemented as a planning context test for consistency
with how the other ignore_changes tests are handled.
Makre sure private data is maintained all the way to destroy. This
slipped through, since private data isn't used much for current
providers, except for timeouts.
Send Private data blob through ReadResource as well. This will allow for
extra flexibility for future providers that may want to pass data out of
band through to their resource Read functions.
The config is statically validated early on for structural issues, but
the provider can't validate any inputs that were unknown at the time.
Run ValidateResourceTypeConfig during Plan, so that the provider can
validate the final config values, including those interpolated from
other resources.
* core: don't panic in NodeAbstractResourceInstance References()
It is possible for s.Current to be nil. This was hard to reproduce, so
the root cause is still unknown, but we can guard against the symptom.
* add log statement
This is a "should never happen" case, because we shouldn't ever have
resources in the plan that aren't in the configuration, but since we've
got a report of a crash here (which went away before we got a chance to
debug it) here's just an extra guard to ensure that we'll still exit
gracefully in that case.
If we see this error crop up again in future, it'd be nice to gather a
full trace log so we can see what GraphNodeAttachResourceConfig did and
why it did not attach a configuration.
Previously we tried to short-circuit this if the schema version hadn't
changed and we were already using JSON serialization. However, if we
instead call into UpgradeResourceState every time we can let the provider
or the SDK do some general, systematic normalization and cleanup steps
without always requiring a schema version increase.
What exactly would be fixed up this way is for the SDK to decide, but for
example the SDK might choose to automatically delete from the state
anything that is no longer present in the schema, avoiding the need to
write explicit state migration functions for that common case where the
remedy is always the same.
The actual update logic is delegated to the provider/SDK intentionally so
that it can evolve over time and potentially differ depending on how
each SDK thinks about schema.
With the new ConfigModeAttr, we can now have complex structures come in
as attributes rather than blocks. Previously attributes were either
known, or unknown, and there was no reason to descend into them. We now
need to record the complete path to unknown values within complex
attributes to create a proper diff after shimming the config.
If a datasource's dependencies have planned changes, then we need to
plan a read for the data source, because the config may change once the
dependencies have been applied.
The count for a data resource can potentially depend on a managed resource
that isn't recorded in the state yet, in which case references to it will
always return unknown.
Ideally we'd do the data refreshes during the plan phase as discussed in
#17034, which would avoid this problem by planning the managed resources
in the same walk, but for now we'll just skip refreshing any data
resources with an unknown count during refresh and defer that work to the
apply phase, just as we'd do if there were unknown values in the main
configuration for the data resource.
Earlier on in the v0.12 development cycle we made the decision that the
validation walk should consider input values to always be unknown so that
validation is checking validity for all possible inputs rather than for
a specific set of inputs; checking for a specific set of inputs is the
responsibility of the plan walk.
However, we didn't implement that in the best way: we made the
"terraform validate" command force all of the input variables to unknown
but that was insufficient because it didn't also affect the implicit
validation walk we do as part of "terraform plan" and "terraform apply",
causing those to produce confusingly-different results.
Instead, we'll address the problem directly in the reference resolver code,
ensuring that all variable values will always be treated as an unknown
(of the declared type, so type checking is still possible) during any
validate walk, regardless of which command is running it.
We previously attempted to make the special diff apply behavior for nested
sets of objects work with attribute mode by totally discarding attribute
mode for all shims.
In practice, that is too broad a solution: there are lots of other shimming
behaviors that we _don't_ want when attribute mode is enabled. In
particular, we need to make sure that the difference between null and
empty can be seen in configuration.
As a compromise then, we will give all of the shims access to the real
ConfigMode and then do a more specialized fixup within the diff-apply
logic: we'll construct a synthetic nested block schema and then use that
to run our existing logic to deal with nested sets of objects, while
using the previous behavior in all other cases.
In effect, this means that the special new behavior only applies when the
provider uses the opt-in ConfigMode setting on a particular attribute,
and thus this change has much less risk of causing broad, unintended
regressions elsewhere.
When an operation fails, providers may return a null new value rather than
returning a partial state. In that case, we'd prefer to keep the old value
so that we stand the best chance of being able to retry on a subsequent
run.
Previously we were making an exception for the delete action, allowing
the result of that to be null even when an error is returned. In practice
that was a bad idea because it would cause Terraform to lose track of the
object even though it might not actually have been deleted.
Now we'll retain the old object even in the delete case. Providers can
still return partial new objects if they were able to partially complete
a delete operation, in which case we'll discard what we had before, but
if the result is null with errors then we'll assume the delete failed
entirely and so just keep the old state as-is, giving us the opportunity
to refresh it on the next run to see if anything actually happened after
all.
(This also includes a new resource in the test provider which isn't used
by the patch but was useful for some manual UX testing here, so I thought
I'd include it in case it's similarly useful in future, given how simple
its implementation is.)
In study of existing providers we've found a pattern we werent previously
accounting for of using a nested block type to represent a group of
arguments that relate to a particular feature that is always enabled but
where it improves configuration readability to group all of its settings
together in a nested block.
The existing NestingSingle was not a good fit for this because it is
designed under the assumption that the presence or absence of the block
has some significance in enabling or disabling the relevant feature, and
so for these always-active cases we'd generate a misleading plan where
the settings for the feature appear totally absent, rather than showing
the default values that will be selected.
NestingGroup is, therefore, a slight variation of NestingSingle where
presence vs. absence of the block is not distinguishable (it's never null)
and instead its contents are treated as unset when the block is absent.
This then in turn causes any default values associated with the nested
arguments to be honored and displayed in the plan whenever the block is
not explicitly configured.
The current SDK cannot activate this mode, but that's okay because its
"legacy type system" opt-out flag allows it to force a block to be
processed in this way anyway. We're adding this now so that we can
introduce the feature in a future SDK without causing a breaking change
to the protocol, since the set of possible block nesting modes is not
extensible.
For compatibility with documented patterns from existing providers we are
now allowing (via a pre-processing step) any attribute whose type is a
list-of-object or set-of-object type to optionally be assigned using one
or more blocks whose type is the attribute name.
The pre-processing functionality was implemented in previous commits but
we were not correctly detecting references within these blocks that are,
from the perspective of the primary schema, invalid. Now we'll use an
alternative implementation of variable detection that is able to apply the
same schema rewriting technique we used to implement the transform and
thus can find all of the references as if they were already in their
final locations.
When a resource type schema includes dynamically-typed attributes we can't
do any automatic conversion from flatmap to JSON because we don't know
how to interpret the keys that start with the dynamically-typed
attribute's prefix.
To work around that, we'll instead just ask the SDK to do a no-op upgrade
(current and target versions are the same) which will convert from flatmap
to JSON using the SDK's own logic as a side-effect.
This situation should rarely arise in real-world use, but it ends up being
very important for the helper/resource provider test harness because it
is forced to lower the state back to flatmap repeatedly after every step
in order to run legacy checking and processing code.
The hcldec package has no awareness of the dynamic block extension, so the
hcldec.Variables function misses any variables declared inside dynamic
blocks.
dynblock.VariablesHCLDec is a drop-in replacement for hcldec.Variables
that _is_ aware of dynamic blocks, returning all of the same variables
that hcldec would find naturally plus also any variables used inside
the dynamic block "for_each" and "labels" arguments and inside the
nested "content" block.
Our post-refresh safety check had the constraint and real type inverted,
so previously any refresh of a resource type with a dynamically-typed
attribute would fail this type check.
Also includes a small tweak to the error message from this check since the
old one was a little awkward to read in practice when the error is a
cty.PathError rendered with an attribute path prefix.
If a block is uneffected by diffs, keep the block count value regardless
of what it is. Blocks containing zero values will often be represented
by only the count value.
We are now allowing the legacy SDK to opt out of the safety checks we try
to do after plan and apply, and so in such cases the before/after values
in planned changes may be inconsistent with our usual rules.
To avoid adding lots of extra complexity to the diff renderer to deal with
these situations, instead we'll normalize the handling of nested blocks
prior to using these values.
In the long run it'd be better to do this normalization at the source,
immediately after we receive an object from a provider using the opt-out,
but we're doing this at the outermost layer for now to avoid risking
unintended impacts on other Terraform Core components when we're just
about to enter the beta phase of the v0.12.0 release cycle.
This uses the fixed "superset" schema from the main terraform package to
apply our standard expression mapping, with the exception of "type" where
interpolation sequences are not supported due to the type being evaluated
early to retrieve the schema for decoding the rest.
The init error was output deep in the backend by detecting a
special ResourceProviderError and formatted directly to the CLI.
Create some Diagnostics closer to where the problem is detected, and
passed that back through the normal diagnostic flow. While the output
isn't as nice yet, this restores the helpful error message and makes the
code easier to maintain. Better formatting can be handled later.
A provider may react to a create or update failing by returning error
diagnostics and a partially-updated or nil new value, in which case we
do not expect our AssertObjectCompatible consistency check to succeed: the
provider is just assumed to be doing the best it can to preserve whatever
partial outcome it was able to achieve.
However, if errors are accompanied with a nil new value after an update,
we'll assume that the provider is telling us it wasn't able to get far
enough to make any change at all, and so we'll retain the prior value in
state. This ensures that a provider can't cause an object to be forgotten
from the state just because an update failed.
RequiresReplace paths with IndexSteps that have been added or removed
may fail to apply against one of the two state values. Only error out if
the path cannot be applied to both values.
Prior to Terraform 0.12 there were certain behaviors we expected from
providers that were actually just details of the SDK and not part of the
enforced contract.
For 0.12 we're now codifying some of these behaviors explicitly via safety
checks in core, thus ensuring that all future providers will behave in a
consistent way that users can rely on.
Unfortunately, due to the hand-written nature of the mock provider
implementations we use in tests, they have been getting away with some
unusual behaviors that don't match our usual expectations, and our safety
checks now detect those as incorrect behaviors.
To address this, we make the minimal changes to each test to ensure that
its mock provider behaves in a consistent way, which requires that values
set in config be represented correctly in the plan and ultimately saved
in the new state, without any changes along the way. In particular, the
common testDiffFn implementation has historically used a number of special
hidden attributes to trigger special behaviors, and our new rules require
that these special settings propagate properly through the plan and into
the state.
Due to the inprecision of our shimming from the legacy SDK type system to
the new Terraform Core type system, the legacy SDK produces a number of
inconsistencies that produce only minor quirky behavior or broken
edge-cases. To retain compatibility with those existing weird behaviors,
the legacy SDK opts out of our safety checks.
The intent here is to allow existing providers to continue to do their
previous unsafe behaviors for now, accepting that this will allow certain
quirky bugs from previous releases to persist, and then gradually migrate
away from the legacy SDK and remove this opt-out on a per-resource basis
over time.
As with the apply-time safety check opt-out, this is reserved only for
the legacy SDK and must not be used in any new SDK implementations. We
still include any inconsistencies as warnings in the logs as an aid to
anyone debugging weird behavior, so that they can see situations where
blame may be misplaced in the user-visible error messages.
We've allowed the legacy SDK an opt-out from the post-apply safety checks,
but previously we produced only a generic warning message in that case.
Now instead we'll still run the safety checks, but report the results in
the logs instead of as error diagnostics.
This should allow developers who are debugging strange interactions
between buggy legacy providers to get better insight into what's going
on upstream in order to help explain what's going on when these problems
inevitably get caught by other downstream safety checks when trying to
make use of these invalid results.
We've been gradually adding safety checks of this sort throughout the
lifecycle to help ensure that buggy providers can't introduce
hard-to-diagnose downstream failures and misbehavior. This completes the
set by verifying during plan time that the provider has produced a plan
that actually achieves the goals defined in the configuration.
In particular, this catches the situation where a provider may incorrectly
override a value explicitly set in configuration, which avoids creating
confusion by betraying the reasonable user expectation that referencing an
explicitly-defined attribute will produce exactly the value shown in
configuration.
The helper/schema handling of lists loses empty string values, but
retains the correct count. Only re-count the values if the count is
missing entirely, and allow our shims to re-populate the zero values.
In an earlier commit we changed objchange.ProposedNewObject so that the
task of populating unknown values for attributes not known during apply
is the responsibility of the provider's PlanResourceChange method, rather
than being handled automatically.
However, we were also using objchange.ProposedNewObject to construct the
placeholder new object for a deferred data resource read, and so we
inadvertently broke that deferral behavior. Here we restore the old
behavior by introducing a new function objchange.PlannedDataResourceObject
which is a specialized version of objchange.ProposedNewObject that
includes the forced behavior of populating unknown values, because the
provider gets no opportunity to customize a deferred read.
TestContext2Plan_createBeforeDestroy_depends_datasource required some
updates here because its implementation of PlanResourceChange was not
handling the insertion of the unknown value for attribute "computed".
The other changes here are just in an attempt to make the flow of this
test more obvious, by clarifying that it is simulating a -refresh=false
run, which effectively forces a deferred read since we skip the eager
read that would normally happen in the refresh step.
Now that ProposedNewState uses null to represent Computed attributes not
set in the configuration, the provider must fill in the unknown value for
"computed" in its plan result.
It seems that this test was incorrectly updated during our bulk-fix after
integrating the HCL2 work, but it didn't really matter because the
ReadDataSource function isn't called in the happy path anyway. But to
make the intent clearer here, we also now make ReadDataSource return an
error if it is called, making it explicit that no call is expected.
Data resources do not have a plan/apply distinction, so it is never valid
for a data resource to produce unknown values in its result object.
Unknown values in the data resource _config_ cause us to postpone the read
altogether, so a data source never receives unknown values as input and
therefore may never produce unknown values as output.
The shim layer for the legacy SDK type system is not precise enough to
guarantee it will produce identical results between plan and apply. In
particular, values that are null during plan will often become zero-valued
during apply.
To avoid breaking those existing providers while still allowing us to
introduce this check in the future, we'll introduce a rather-hacky new
flag that allows the legacy SDK to signal that it is the legacy SDK and
thus disable the check.
Once we start phasing out the legacy SDK in favor of one that natively
understands our new type system, we can stop setting this flag and thus
get the additional safety of this check without breaking any
previously-released providers.
No other SDK is permitted to set this flag, and we will remove it if we
ever introduce protocol version 6 in future, assuming that any provider
supporting that protocol will always produce consistent results.
Previously we would allow providers to change anything about the planned
object value during apply, possibly returning an entirely-unrelated object
of the same type. In practice this led to some subtle bugs where a single
planned attribute value would change during apply and cause a downstream
failure due to a dependent resource now seeing input other than what
_it_ expected during plan.
Now we'll produce an explicit error message for this case which places the
blame with the correct party: the upstream resource that changed. Without
this, unexpected changes would often lead to the downstream resource
implementation being blamed in error message even though it was just
reacting to the change from upstream.
As with most errors during apply, we'll still save the updated value in
the state but we'll halt the walk to ensure that the unexpected value
cannot propagate further and cause the result to potentially diverge
greatly from the changeset shown in the plan.
Compared to Terraform 0.11, we expect to see this error in many of the
same cases we saw the "diffs didn't match during apply" error in earlier
versions, since it is likely that many errors of that sort were the result
of unexpected upstream changes being incorrectly blamed on the downstream
resource that then used the result.
Because Terraform Core has traditionally not checked that the final apply
result is consistent with what was planned, some of our apply tests were
producing inconsistent results.
Here we fix all of that so that they produce something compatible with
what they planned. This doesn't actually achieve anything in isolation,
but we're about to start enforcing this consistency in a subsequent
commit.
We were previously using cty.Path.Apply, which serves a similar purpose
but implements the more restrictive traversal behaviors down at the cty
layer. hcl.ApplyPath uses the same rules as HCL expressions and so ensures
consistent behavior with normal user expressions.
cty.Path.Apply also previously had a crashing bug (discussed in #20084)
that was causing a panic here. That has now been fixed in cty, but since
we're no longer using it here that's a moot point. The HCL traversing
implementation has been fuzz-tested and unit tested a lot more thoroughly
so should not run into the same crashers we saw with cty before.
When elements are removed from a list, all attributes may not be present
in the diff. Once the individual attributes diffs are applied, use the
length to truncate the flatmapped list to the correct length.
If there were no matching keys, and there was no diff at all, don't set
a zero count for the container. Normally Providers can't reliably detect
empty vs unset here, but there are some cases that worked.
Missing prefix in map recount. This generally passes tests since the
actual count should already be there and be correct, then ethe extra key
is ignored by the shims.
The previous version assumed the diff could be applied verbatim, and
only used the schema at the top level since diffs are "flat". This
turned out to not work reliably with nested blocks. The new Apply method
is driven completely by the schema, and handles nested blocks separately
from other collections.
In an ideal world, providers are supposed to respond to errors during
apply by returning a partial new state alongside the error diagnostics.
In practice though, our SDK leaves the new value set to nil for certain
errors, which was causing Terraform to "forget" the object altogether by
assuming that the provider intended to say "null".
We now adjust that assumption to apply only in the delete case. In all
other cases (including updates) we retain the prior state if the new
state is given as nil. Although we could potentially fix this in the SDK
itself, I expect this is a likely bug in other future SDKs for other
languages too, so this new assumption is a safer one to make to be
resilient to data loss when providers don't behave perfectly.
Providers that return both nil new value and no errors are considered
buggy, but unfortunately that applies to the mocks in many of our tests,
so for pragmatic reasons we can't generate an error for that case as we do
for other "should never happen" situations. Instead, we'll just retain the
prior value in the state so the user can retry.
There are a few constructs from 0.11 and prior that cause 0.12 parsing to
fail altogether, which previously created a chicken/egg problem because
we need to install the providers in order to run "terraform 0.12upgrade"
and thus fix the problem.
This changes "terraform init" to use the new "early configuration" loader
for module and provider installation. This is built on the more permissive
parser in the terraform-config-inspect package, and so it allows us to
read out the top-level blocks from the configuration while accepting
legacy HCL syntax.
In the long run this will let us do version compatibility detection before
attempting a "real" config load, giving us better error messages for any
future syntax additions, but in the short term the key thing is that it
allows us to install the dependencies even if the configuration isn't
fully valid.
Because backend init still requires full configuration, this introduces a
new mode of terraform init where it detects heuristically if it seems like
we need to do a configuration upgrade and does a partial init if so,
before finally directing the user to run "terraform 0.12upgrade" before
running any other commands.
The heuristic here is based on two assumptions:
- If the "early" loader finds no errors but the normal loader does, the
configuration is likely to be valid for Terraform 0.11 but not 0.12.
- If there's already a version constraint in the configuration that
excludes Terraform versions prior to v0.12 then the configuration is
probably _already_ upgraded and so it's just a normal syntax error,
even if the early loader didn't detect it.
Once the upgrade process is removed in 0.13.0 (users will be required to
go stepwise 0.11 -> 0.12 -> 0.13 to upgrade after that), some of this can
be simplified to remove that special mode, but the idea of doing the
dependency version checks against the liberal parser will remain valuable
to increase our chances of reporting version-based incompatibilities
rather than syntax errors as we add new features in future.
In prior versions of Terraform we permitted inconsistent use of indexes
in resource references, but in as of 0.12 the index usage must correlate
properly with whether "count" is set on the resource.
Since users are likely to have existing configurations with incorrect
usage, here we introduce some specialized error messages for situations
where we can detect such issues statically. This seems to cover all of the
common patterns we've seen in practice.
Some usage patterns will fall back on a less-helpful dynamic error here,
but no configurations coming from 0.11 can end up that way because 0.11
did not permit forms such as aws_instance.no_count[count.index].bar that
this validation would not be able to "see".
Our configuration upgrade tool also contains a fix for this already, but
it takes a more conservative approach of adding the index [1] rather than
[count.index] because it can't be sure (without human help) if correlation
of indices is what was intended.
Previously we used the native slash type for the host platform, but that
leads to issues if the same configuration is applied on both Windows and
non-Windows systems.
Since Windows supports slashes and backslashes, we can safely return
always slashes here and require that users combine the result with
subsequent path parts using slashes, like:
"${path.module}/foo/bar"
Previously the above would lead to an error on Windows if path.module
contained any backslashes.
This is not really possible to unit test directly right now since we
always run our tests on Unix systems and filepath.ToSlash is a no-op on
Unix. However, this does include some tests for the basic behavior to
verify that it's not regressed as a result of this change.
This will need to be reported in the changelog as a potential breaking
change, since anyone who was using Terraform _exclusively_ on Windows may
have been using expressions like "${path.module}foo\\bar" which they will
now need to update.
This fixes#14986.
We already catch indirect cycles through the normal cycle detector, but
we never create self-edges in the graph so we need to handle a direct
self-reference separately here.
The prior behavior was simply to produce an incorrect result (since the
local value wasn't assigned a new value yet).
This fixes#18503.
James Bardin