New tar archive sets file perms and last modified timestamps incorrectly

[lewisdan91]

Terraform CLI and Provider Versions

Terraform v1.8.3
hashicorp/archive version 2.6.0

Terraform Configuration

data "archive_file" "create_tar" {
  type        = "tar.gz"
  output_path = "mytar.tgz"
  output_file_mode = 0644

  source {
    content  = local_file.bundle_json.content
    filename = local.bundle
  }

  source {
    content  = data.local_file.main_js.content
    filename = local.main_js
  }
}

Expected Behavior

Files inside tar should have correct file permissions and retain last modified timestamps.

Actual Behavior

If output_file_mode is set, random file perms and incorrect last modified timestamps are shown:

$ tar -xvf mytar.tgz 
bundle.json
main.js
$ ls -l
total 32
--w----r-- 1 daniel users    83 Jan  1  1970 bundle.json
--w----r-- 1 daniel users 12746 Jan  1  1970 main.js
-rw-r--r-- 1 daniel users  3929 Sep 18 14:05 mytar.tgz

If no output_file_mode is set no file perms are set and incorrect last modified timestamps are shown:

$ tar -xvf mytar.tgz 
bundle.json
main.js
$ ls -l
total 32
---------- 1 daniel users    83 Jan  1  1970 bundle.json
---------- 1 daniel users 12746 Jan  1  1970 main.js
-rw-r--r-- 1 daniel users  3922 Sep 18 14:03 mytar.tgz

Steps to Reproduce

1. terraform apply

How much impact is this issue causing?

High

Logs

No response

Additional Information

No response

Code of Conduct

• I agree to follow this project's Code of Conduct

[eriksw]

Having file timestamps in the archive be fixed at the epoch facilitates making the resulting archive representative of the contents in a reproducible/deterministic way. Having the contents of the archive not change unless the contents of the files in it change is a desirable feature in many (probably the overwhelming majority) of use cases, because it allows you to drive other resource updates to happen only when there is an actual change to the contents.

If there was a compelling use case for archives including "real" timestamps, that feature/behavior would need to be opt-in and not a change to the default. Deterministic/reproducible archives are not a bug.