Prior to Terraform 0.7, lists in Terraform were just a shallow abstraction
on top of strings with a magic delimiter between items. Wrapping a single
string in brackets in the configuration was Terraform's prompt that it
needed to split the string on that delimiter during interpolation.
In 0.7, when first-class lists were added, this convention was preserved
by flattening lists-of-lists by one level when they were encountered in
configuration. However, there was an oversight in that change where it
did not correctly handle the case where the inner list was unknown.
In #14135 we removed some code that was flattening partially-unknown lists
into fully-unknown (untyped) values. This inadvertently exposed the missed
case from the previous paragraph, causing issues for list-wrapped splat
expressions with unknown members. While this worked fine for resources,
due to some fixup done inside helper/schema, this did not work for other
interpolation contexts such as module blocks.
Various attempts to fix this up and restore the flattening behavior
selectively were unsuccessful, due to a proliferation of assumptions all
over the core code that would be too risky to change just to fix this bug.
This change, then, takes the different approach of removing the
requirement that splats be presented inside list brackets. This
requirement didn't make much sense anymore anyway, since no other
list-returning expression had this constraint and so the rest of Terraform
was already successfully dealing with both cases.
This leaves us with two different scenarios:
- For resource arguments, existing normalization code in helper/schema
does its own flattening that preserves compatibility with the common
practice of using bracketed splats. This change proves this with a test
within the "test" provider that exercises the whole Terraform core and
helper/schema stack that assigns bracketed splats to list and set
attributes.
- For arguments in other blocks, such as in module callsites, the
interpolator's own flattening behavior applies to known lists,
preserving compatibility with configurations from before
partially-computed splats were possible, but those wishing to use
partially-computed splats are required to drop the surrounding brackets.
This is less concerning because this scenario was introduced only in
0.9.5, so the scope for breakage is limited to those who adopted this
new feature quickly after upgrading.
As of this commit, the recommendation is to stop using brackets around
splats but the old form continues to be supported for backward
compatibility. In a future _major_ version of Terraform we will probably
phase out this legacy form to improve consistency, but for now both
forms are acceptable at the expense of some (pre-existing) weird behavior
when _actual_ lists-of-lists are used.
This addresses #14521 by officially adopting the suggested workaround of
dropping the brackets around the splat. However, it doesn't yet allow
passing of a partially-unknown list between modules: that still violates
assumptions in Terraform's core, so for the moment partially-unknown lists
work only within a _single_ interpolation expression, and cannot be
passed around between expressions. Until more holistic work is done to
improve Terraform's type handling, passing a partially-unknown splat
through to a module will result in a fully-unknown list emerging on
the other side, just as was the case before #14135; this change just
addresses the fact that this was failing with an error in 0.9.5.
> This validation checks that there are now splat variables referencing ourself. This currently is not allowed.
=>
> This validation checks that there are no splat variables referencing ourself. This currently is not allowed.
We've been incorrectly validating (or not validating at all) the
requirement that certain blocks be followed by a name string, to prohibit
e.g. this:
variable {}
and:
variable = ""
Before this change we were catching this for most constructs only if
there were no _valid_ blocks of the same name in the same file. For
modules in particular, we were not catching this at all.
Now we detect this for all kinds of block (resources had a pre-existing
check, so aren't touched here) and produce a different error message
depending on which of the above incorrect forms are used.
This fixes#13575.
stringer has changed the boilerplate it generates in a recent version.
We'd previously updated to the new format but accientally rolled back
to the old while merging a long-running feature branch.
This restores us back to the new format again.
This new function allows using a search within one list to filter another list. For example, it can be used to find the ids of EC2 instances in a particular AZ.
The interface is made slightly awkward by the constraints of HIL's featureset.
#13847
This method mirrors that of config.Backend, so we can compare the
configration of a backend read from a config vs that of a backend read
from a state. This will prevent init from reinitializing when using
`-backend-config` options that match the existing state.
The variable validator assumes that any AST node it gets from an
interpolation walk is an indicator of an interpolation. Unfortunately,
back in f223be15 we changed the interpolation walker to emit a LiteralNode
as a way to signal that the result is a literal but not identical to the
input due to escapes.
The existence of this issue suggests a bit of a design smell in that the
interpolation walker interface at first glance appears to skip over all
literals, but it actually emits them in this one situation. In the long
run we should perhaps think about whether the abstraction is right here,
but this is a shallow, tactical change that fixes#13001.
golang/tools commit 23ca8a263 changed the format of the leading comment
to comply with some new standards discussed here:
https://golang.org/issue/13560
This is the result of running generate with the latest version of
stringer. Everyone working on Terraform will need to update stringer
after this is merged, to avoid reverting this:
go get -u golang.org/x/tools/cmd/stringer
Adds `basename` and `dirname` interpolation. I want to add a `stack` tag to our infrastructure, the value of which is set to `${basename(path.cwd)}`. We currently use `${replace(path.cwd, "/^.+\\//", "")}` instead, but this is extremeley unreadable. The existance of a `basename` function would be very useful for this use case.
I don't have an immediate use case for a `dirname` function, but it seemed reasonable to add it as well.
When configuration is read out of JSON, HCL assumes that empty levels of
objects can be flattened, but this removes too much to decode into a
config.Terraform struct.
Reconstruct the appropriate AST to decode the config struct.
Ensure that fields set in an earlier Terraform config block aren't
removed by Append when encountering another Terraform block. When
multiple blocks contain the same field, the later one still wins.
Fixes#12788
We would panic when referencing an output from an undefined module. The
panic above this is correct but in this case Load will not catch
interpolated variables that _reference_ an unloaded/undefined module.
Test included.
It can be tedious fixing a new module with many errors when Terraform
only outputs the first random error it encounters.
Accumulate all errors from validation, and format them for the user.
Fixes#11800
Type check the value of count so we don't panic on the conversion.
I wondered "why didn't we do this before?" There is no excuse for NOT
doing it at all but the reasoning was beacuse prior to the list/map work
in 0.7, the value couldn't be anything other than a string since any
primitive can turn into a string.
Regardless, we should've always done this.
This disables the computed value check for `count` during the validation
pass. This enables partial support for #3888 or #1497: as long as the
value is non-computed during the plan, complex values will work in
counts.
**Notably, this allows data source values to be present in counts!**
The "count" value can be disabled during validation safely because we
can treat it as if any field that uses `count.index` is computed for
validation. We then validate a single instance (as if `count = 1`) just
to make sure all required fields are set.
Radek Simko