Add a new ChangeReason, ReasonDeleteBecauseNoMoveTarget, to provide better
information in cases where a planned deletion is due to moving a resource to
a target not in configuration.
Consider a case in which a resource instance exists in state at address A, and
the user adds a moved block to move A to address B. Whether by the user's
intention or not, address B does not exist in configuration.
Terraform combines the move from A to B, and the lack of configuration for B,
into a single delete action for the (previously nonexistent) entity B.
Prior to this commit, the Terraform plan will report that resource B will be
destroyed because it does not exist in configuration, without explicitly
connecting this to the move.
This commit provides the user an additional clue as to what has happened, in a
case in which Terraform has elided a user's action and inaction into one
potentially destructive change.
Go 1.19's "fmt" has some awareness of the new doc comment formatting
conventions and adjusts the presentation of the source comments to make
it clearer how godoc would interpret them. Therefore this commit includes
various updates made by "go fmt" to acheve that.
In line with our usual convention that we make stylistic/grammar/spelling
tweaks typically only when we're "in the area" changing something else
anyway, I also took this opportunity to review most of the comments that
this updated to see if there were any other opportunities to improve them.
We previously had a special case in the graph transformer for output
values where it would directly create an individual output value node
instead of an "expand" node as we would do for output values in nested
modules.
While it's true that we do always know that expanding a root module
output value will always produce exactly one instance, treating this case
as special creates the risk of those two codepaths diverging in other
ways.
Instead, we'll let the expand node also deal with root modules and
minimize the special case only to how we look up any changes for the
output values, since the design of plans.Changes is a bit awkward and
requires us to ask the question differently for root module output values.
Otherwise, the behavior will now be consistent across all output values
regardless of module.
We have two different reasons why a data resource might be read only
during apply, rather than during planning as usual: the configuration
contains unknown values, or the data resource as a whole depends on a
managed resource which itself has a change pending.
However, we didn't previously distinguish these two in a way that allowed
the UI to describe the difference, and so we confusingly reported both
as "config refers to values not yet known", which in turn led to a number
of reasonable questions about why Terraform was claiming that but then
immediately below showing the configuration entirely known.
Now we'll use our existing "ActionReason" mechanism to tell the UI layer
which of the two reasons applies to a particular data resource instance.
The "dependency pending" situation tends to happen in conjunction with
"config unknown", so we'll prefer to refer that the configuration is
unknown if both are true.
replace_triggered_by references are scoped to the current module, so we
need to filter changes for the current module instance. Rather than
creating a ConfigResource and filtering the result, make a
Changes.InstancesForAbsResource method to get only the AbsResource
changes.
There are a few different reasons why a resource instance tracked in the
prior state might be considered an "orphan", but previously we reported
them all identically in the planned changes.
In order to help users understand the reason for a surprising planned
delete, we'll now try to specify an additional reason for the planned
deletion, covering all of the main reasons why that could happen.
This commit only introduces the new detail to the plans.Changes result,
though it also incidentally exposes it as part of the JSON plan result
in order to keep that working without returning errors in these new
cases. We'll expose this information in the human-oriented UI output in
a subsequent commit.
For resources which are planned to move, render the previous run address
as additional information in the plan UI. For the case of a move-only
resource (which otherwise is unchanged), we also render that as a
planned change, but without any corresponding action symbol.
If all changes in the plan are moves without changes, the plan is no
longer considered "empty". In this case, we skip rendering the action
symbols in the UI.
In order to expose the effect of any relevant "moved" statements we dealt
with prior to creating the plan, we'll record with each
ResourceInstanceChange both is current address and the address it was
tracked at for the previous run.
To save consumers of these objects from having to special-case the
situation where there _was_ no previous run (e.g. because this is a Create
change), we'll just pretend the previous run address was the same as the
current address in that case, the same as for an update without any
renaming in effect.
This includes a breaking change to the plan file format, but one that
doesn't require a version number increment because there is no ambiguity
between the two formats and so mismatched parsers will already fail with
an error message.
As of this commit we've just added the new field but not yet populated it
with any useful information: it always just matches Addr. A future commit
will wire this up to the result of applying the moves so that we can
populate it correctly. We also don't yet expose this new information
anywhere in the UI layer.
This is part of a general effort to move all of Terraform's non-library
package surface under internal in order to reinforce that these are for
internal use within Terraform only.
If you were previously importing packages under this prefix into an
external codebase, you could pin to an earlier release tag as an interim
solution until you've make a plan to achieve the same functionality some
other way.
This is part of a general effort to move all of Terraform's non-library
package surface under internal in order to reinforce that these are for
internal use within Terraform only.
If you were previously importing packages under this prefix into an
external codebase, you could pin to an earlier release tag as an interim
solution until you've make a plan to achieve the same functionality some
other way.
