terraform-provider-pagerduty: `time_zone` validation breaks provider when tz database is missing

PR #473 breaks a lot of assumptions that are made about terraform providers. Currently my Mac and our CI/CD Docker containers don’t have the ZONEINFO defined. We should support gracefully falling back to no validation if this doesn’t exist and throw a warning and/or add better information about why the error occurred for end users.

// LoadLocation returns the Location with the given name.
//
// If the name is "" or "UTC", LoadLocation returns UTC.
// If the name is "Local", LoadLocation returns Local.
//
// Otherwise, the name is taken to be a location name corresponding to a file
// in the IANA Time Zone database, such as "America/New_York".
//
// The time zone database needed by LoadLocation may not be
// present on all systems, especially non-Unix systems.
// LoadLocation looks in the directory or uncompressed zip file
// named by the ZONEINFO environment variable, if any, then looks in
// known installation locations on Unix systems,
// and finally looks in $GOROOT/lib/time/zoneinfo.zip.

https://github.com/golang/go/blob/go1.16/src/time/zoneinfo.go#L615-L628

Terraform Version

$ terraform --version
Terraform v1.1.7
on darwin_arm64

Affected Resource(s)

Please list the resources as a list, for example:

• pagerduty/resource_pagerduty_ruleset_rule.go
• pagerduty/resource_pagerduty_schedule.go
• pagerduty/resource_pagerduty_service.go
• pagerduty/resource_pagerduty_service_event_rule.go
• pagerduty/resource_pagerduty_user.go

Terraform Configuration Files

...
time_zone = "America/Los_Angles"
...

Debug Output

Error: unknown time zone America/Los_Angeles
with module.pagerduty.pagerduty_schedule.default["primary"],
on ../../../../providers/pagerduty/modules/bundle/schedule.tf line 34, in resource "pagerduty_schedule" "default":
   34:   time_zone = lookup(each.value, "time_zone", "America/Los_Angeles")

Panic Output

If Terraform produced a panic, please provide a link to a GitHub Gist containing the output of the crash.log.

Expected Behavior

Timezones that are defined work without failing.

Actual Behavior

Timezones aren’t found when the timezone database is missing.

Steps to Reproduce

1. terraform apply when a time_zone is defined and there is no timezone database present.

References

Are there any other GitHub issues (open or closed) or Pull Requests that should be linked here? For example:

• #473
• https://github.com/golang/go/blob/go1.16/src/time/zoneinfo.go#L615-L628

Workaround / fix

apt-get install tzdata