Previously we would write to the backend for every call to PersistState,
even if nothing changed since the last write, but update the serial only
if the state had changed.
The Terraform Cloud & Enterprise state storage have a simple safety check
that any future write with an already-used lineage and serial must be
byte-for-byte identical. StatesMarshalEqual is intended to detect that,
but it only actually detects changes the state itself, and not changes
to the snapshot metadata.
Because we write the current Terraform version into the snapshot metadata
during serialization, we'd previously have an issue where if the first
state write after upgrading Terraform to a new version happened to change
nothing about the state content then we'd write a new snapshot that
differed only by Terraform version, and Terraform Cloud/Enterprise would
then reject it.
The snapshot header is discarded immediately after decoding, so we can't
use information from it when deciding whether to increment the serial.
The next best thing is to skip sending no-op snapshot updates to the state
client in the first place.
These writes are unnecessary anyway, and state storage owners have asked
us in the past to elide these to avoid generating noise in their version
logs, so we'll also finally meet those requests as a nice side-effect of
this change.
We didn't previously have tests for the full flow of retrieving and then
successively updating persisted state snapshots, so this includes a test
which covers that logic and includes an assertion that a no-op update does
not get written to the state client.
These statemgr interfaces are the new names for the older interfaces in
the "state" package. These types alias each other so it doesn't really
matter which we use, but the "state" package is deprecated and we intend
to eventually remove it, so this is a further step in that direction.
Load private data for read, so the resource can get it's configured
timeouts if they exist.
Ensure PlanResourceChange returns the saved private data when there is
an empty diff.
Handle the timeout decoding into Meta in the PlanResourceChange, so that
it's always there for later operations.
The helper/schema diff process loses empty strings, causing them to show
up as unset (null) during apply. Besides failing to show as set by
GetOk, the absence of the value also triggers the schema to insert a
default value again during apply.
It would also be be preferable if the defaults weren't re-evaluated
again during ApplyResourceChange, but that would require a more invasive
patch to the field readers, and ensuring the empty string is stored in
the plan should block the default.
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.
This includes a fix to make sure that an expression with a static string
index, like foo["bar"], will be parsed as a traversal rather than as a
dynamic index expression.
* Correct fmt -check
With `-check=false` the exit status is always zero.
With `-check=true` the exit status is zero when all files are properly formatted and non-zero otherwise.
* update fmt documentation to use short form for -diff and -check
We previously had some notes about handling configuration variants just
tacked on to the "dependency inversion" section as an afterthought, but
this idea is a major use-case for dependency inversion so it deserves its
own section and a specific example.
James Bardin