large numbers rendered incorrectly in plan output

[heldersepu]

Terraform Version

Terraform v1.6.2

Terraform Configuration Files

locals {
  ids = [
    9223372036854773256,
    9223372036854773263,
    9223372036854773263,
    9223372036854773266
  ]
  sorted = sort(local.ids)
  unique = distinct(local.ids)
}

output "sorted" {
  value = local.sorted
}

output "unique" {
  value = local.unique
}

Debug Output

Changes to Outputs:
  + sorted = [
      + "9223372036854773256",
      + "9223372036854773263",
      + "9223372036854773263",
      + "9223372036854773266",
    ]
  + unique = [
      + 9223372036854774000,
      + 9223372036854774000,
      + 9223372036854774000,
    ]

Expected Behavior

the distinct function should output full values just like sort does

Actual Behavior

distinct is rounding the values to 9223372036854774000

Steps to Reproduce

just do a TF plan on the sample provided

[jbardin]

Thanks for filing the issue @heldersepu!

I don't think this is actually a problem with distinct, something appears to be going wrong with the rendered output. If you format the numbers within Terraform, you can see the full value:

output "unique" {
  value = [for v in local.unique : format("%d", v)]
}

  + unique = [
      + "9223372036854773256",
      + "9223372036854773263",
      + "9223372036854773266",
    ]

Note that sort here works for the same reason, the sort function operates on strings, so the numbers are implicitly converted before being sorted, which is why your sorted output is in quotes.

[jbardin]

Also checked that the plan has stored the correct list(number) value, and can be verified in the -json output.

[heldersepu]

100% not just the distinct I got the same just outputting the list:

locals {
  ids = [
    9223372036854773256,
    9223372036854773263,
    9223372036854773263,
    9223372036854773266
  ]
}

output "ids" {
  value = local.ids
}

output "sorted" {
  value = sort(local.ids)
}

---

Changes to Outputs:
  + ids    = [
      + 9223372036854774000,
      + 9223372036854774000,
      + 9223372036854774000,
      + 9223372036854774000,
    ]
  + sorted = [
      + "9223372036854773256",
      + "9223372036854773263",
      + "9223372036854773263",
      + "9223372036854773266",
    ]

[heldersepu]

... and yes the terraform.tfstate has the correct values

[liamcervante]

This happens when we read the changes back from the json.RawMessage format they are stored in the json plan file. This is here: https://github.com/hashicorp/terraform/blob/main/internal/command/jsonformat/structured/change.go#L277

Essentially, the numbers are bigger than 2^63, and the json package by default attempts to read them into float64 types, which overflows and then we see the number being truncated.

The fix is relatively simple, we just need to tell the json package to use json.Number to represent numbers instead of float64. We have a lot of tests that need to be updated though to support the new internal representation.

[github-actions]

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