The upgrade tool is assuming that a type of "list" means list(string) and
a type of "map" means map(string), because that was what we documented
those as meaning.
In practice, Terraform 0.11 was lacking some validation which allowed
more complex nested structures in some cases even though they were pretty
inconvenient to use due to other language limitations.
The upgrade tool doesn't have enough context to make a reliable decision
on this, so instead we'll rely on the upgrade guide for this. We don't
need a TF-UPGRADE-TODO comment in this case because we reserve those for
things where a subsequent operation might cause the configuration to be
misinterpred, rather than just causing an error. Instead, we'll show an
example of the comment in the upgrade guide so the reader can easily
match it, and give some advice in the guide on how to address it.
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.
This includes a small fix to ensure the parser doesn't produce an invalid
body for block parsing syntax errors, and instead produces an incomplete
result that calling applications like Terraform can still analyze.
The problem here was affecting our version-constraint-sniffing code, which
intentionally tried to find a core version constraint even if there's a
syntax error so that it can report that a new version of Terraform is a
likely cause of the syntax error. It was working in most cases, unless
it was the "terraform" block itself that contained the error, because then
we'd try to analyze a broken hcl.Block with a nil body.
This includes a new test for "terraform init" that exercises this
recovery codepath.
Having removed the methods, it is straightforward to mechanically update
this file to get rid of all references to the "legacy schema". There is
now only one config schema type to deal with in the sdk.
This experiment is no longer needed for handling computed blocks, since
the legacy SDK can't reasonably handle Dynamic types, we need to remove
this before the final release.
Remove LegacySchema functions as well, since handling SkipCoreTypeCheck
was the only thing left they were handling.
When handling the json state in UpgradeResourceState, the schema
must be what core uses, because that is the schema used for
encoding/decoding the json state.
When converting from flatmap to json state, the legacy schema will be
used to decode the flatmap to a cty value, but the resulting json will
be encoded using the CoreConfigSchema to match what core expects.
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.
We've seen in the past that some users try to use this form with the
ssh:// URL prefix, so we'll mention explicitly that this is invalid and
show a working example of how to use it without the URL scheme prefix.
The "err" variable in the MaybeRelativePathErr condition was masking the
original err with nil in the "else" case of this branch, causing the
error message to be incomplete.
While here, also tweaked the wording to say "Could not download" rather
than "Error attempting to download", both to say the same thing in fewer
words and because the summary line above already starts with "Error:"
when we print out this message, so it looks weird to have both lines
start with the same word.
When normalizing the state during read, if the resource was previously
imported, most nil-able values will be nil, and we need to prefer the
values returned by the latest Read operation. This didn't come up
before, because Read is usually working with a state create by plan and
Apply which has already shaped the state with the expected empty values.
Having the src value preferred only during Apply better follows the
intent of this function, which should allow Read to return whatever
values it deems necessary. Since Read and Plan use the same
normalization logic, the implied Read before plan should take care of any
perpetual diffs.
The new type system only has a Number type, but helper schema
differentiates between Int and Float values. Verify that a new config
value is an integer during Validate, because the existing WeakDecode
validation will decode a float value into an integer while the config
FieldReader will attempt to parse the float exactly.
Since we're limiting this to protoV5, we can be certain that any valid
config value will be converted to an `int` type by the shims. The only
case where an integral float value will appear is if the integer is out
of range for the systems `int` type, but we also need to prevent that
anyway since it would fail to read in the same manner.
Terraform core would previously ignore unexpected attributes found in
the state, but since we now need to encode/decode the state according
the schema, the attributes must match the schema.
On any state upgrade, remove attributes no longer present in the schema
from the state. The only change this requires from providers is that
going forward removal of attribute is considered a schema change, and
requires an increment of the SchemaVersion in order to trigger the
removal of the attributes from state.
Our original upgrade guide was drafted while some things were still in
flux and not all of our upgrade tooling was in place yet.
This redraft now attempts to be more specific and direct, showing exact
commands to run and (where relevant) exact error messages that Terraform
might return.
I also took this opportunity for some general copy-editing, though we'll
probably want to do one more pass of that alone (without changing any
content at the same time) before final release.
This new content presumes the existence of a Terraform v0.11.14 release,
which isn't published yet at the time of writing but should be published
before v0.12.0 final, once we've done final verification and review of
the upgrade path including it.
Computed primitive values must see the UnknownConfigValue or they are
assumed to be unchanged. Restrict the usage of the protov5 ComputedKeys
to containers.
- Note that we intentionally omitted it from the sidebar, to reduce confusion.
- Write a summary up top so you can stop reading sooner if you don't actually need this.
Martin Atkins