Although sets do not have indexed elements, in Terraform 0.11 and earlier
element(...) would work with sets because we'd automatically convert them
to lists on entry to HIL -- with an arbitrary-but-consistent ordering --
and this return an arbitrary-but-consistent element from the list.
The element(...) function in Terraform 0.12 does not allow this because it
is not safe in general, but there was an existing pattern relying on this
in Terraform 0.11 configs which this upgrade rule is intended to preserve:
resource "example" "example" {
count = "${length(any_set_attribute)}"
foo = "${element(any_set_attribute, count.index}"
}
The above works because the exact indices assigned in the conversion are
irrelevant: we're just asking Terraform to create one resource for each
distinct element in the set.
This upgrade rule therefore inserts an explicit conversion to list if it
is able to successfully provide that the given expression will return a
set type:
foo = "${element(tolist(any_set_attribute), count.index}"
This makes the conversion explicit, allowing users to decide if it is
safe and rework the configuration if not. Since our static type analysis
functionality focuses mainly on resource type attributes, in practice this
rule will only apply when the given expression is a statically-checkable
resource reference. Since sets are an SDK-only concept in Terraform 0.11
and earlier anyway, in practice that works out just right: it's not
possible for sets to appear anywhere else in older versions anyway.
The comma-separated syntax is now reserved only for object constructor
expressions in attribute values, so the upgrade tool rewrites block
arguments to be newline-separated instead.
This was already working but we didn't have an explicit test for it until
now.
Prior to Terraform 0.12, ignore_changes was implemented in a
flatmap-oriented fashion and so users found that they could (and in fact,
were often forced to) use the internal .% and .# suffixes flatmap uses to
ignore changes to the number of elements in a list or map.
Terraform 0.12 no longer uses that representation, so we'll interpret
ignoring changes to the length as ignoring changes to the entire
collection. While this is not a totally-equivalent change, in practice
this pattern was most often used in conjunction with specific keys from a
map in order to _effectively_ ignore the entire map, even though Terraform
didn't really support that.
* command/jsonconfig: provider config marshaling enhancements
This PR fixes a bug wherein the keys in "provider_config" were the
"addrs.ProviderConfig", and therefore being overwritten for each module,
instead of the intended "addrs.AbsProviderConfig".
We realized that there was still opportunity for ambiguity, for example
if a user made a provider alias that was the same name as a module, so
we opted to use the syntax `modulename:providername(.provideralias)`
* command/json*: fixed a bug where we were attempting to lookup schemas
with the provider name, instead of provider type.
HIL implemented its type conversions by rewriting its AST to include calls
to some undocumented builtin functions. Unfortunately those functions were
still explicitly callable if you could figure out the name for them, and
so they may have been used in the wild.
In particular, __builtin_StringToFloat was used as part of a workaround
for a HIL design flaw where it would prefer to convert strings to integers
rather than floats when performing arithmetic operations. This issue was,
indeed, the main reason for unifying int ant float into a single number
type in HCL. Since we published that as a suggested workaround, the
upgrade tool ought to fix it up.
The other cases have never been documented as a workaround, so they are
less likely to appear in the wild, but we might as well fix them up anyway
since we already have the conversion functions required to get the same
result in the new language.
To be safe/conservative, most of these convert to _two_ function calls
rather than just one, which ensures that these new expressions retain the
behavior of implicitly converting to the source type before running the
conversion. The new conversion functions only specify target type, and so
cannot guarantee identical results if the argument type does not exactly
match what was previously given as the parameter type in HIL.
HEREDOC tokens are a little more fussy than normal string sequences
because we need to preserve the whitespace within them along with the
start and end markers while we upgrade any interpolated expressions inside.
We need to do some work locally here because the HCL heredoc processing
"does too much" and throws away information we need to do a faithful
upgrade.
We also need to contend with the fact that Terraform <=0.11 had an older
version of HCL that accidentally permitted a degenerate form of heredoc
where the marker was at the end of the final line, like this:
degenerate = <<EOT
this should never have workedEOT
When we migrate this, we'll introduce the additional newline that is now
required, which will unfortunately slightly change the result string to
include a newline when parsed by 0.12, and so we'll need to call this out
as a caveat in the upgrade guide.
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.
Nick Fagerlund