Microsoft/OSInfo: version operators and codename don’t work on rolling-release distributions like Arch Linux #1777

Prerequisites

• Write a descriptive title.
• Make sure you are able to repro it on the latest version
• Search the existing issues.

Summary

Microsoft/OSInfo doesn't work correctly on ArchLinux since /etc/os-release is rolling and there is no versions or codenames.

Steps to reproduce

On Arch Linux (/etc/os-release has ID=arch, BUILD_ID=rolling, no VERSION_ID or VERSION_CODENAME), with DSC 3.3.0:

dsc resource get -r Microsoft/OSInfo
{"actualState":{"family":"Linux","version":"Rolling Release","bitness":64,"architecture":"x86_64"}}

Version operators: osinfo.tests.ps1 builds its "valid version constraints" cases from the current version, so on Arch it tests = Rolling Release, >= Rolling Release and so on. parse_version_constraint only recognises an operator if a digit follows it, so these are treated as literal strings and never match:

echo '{"version":">= Rolling Release"}' | dsc resource test -r Microsoft/OSInfo -f -
... "inDesiredState":false,"differingProperties":["version"]

The > and < cases only pass by accident, because the literal string doesn't match either.

Codename: Arch has no codename, so codename is missing from the actual state.

• The test should be in desired state when codename matches actual sends {"codename": null}, which fails schema validation (null is not of type "string") with exit code 2.

• should not be in desired state when codename does not match sends {"codename":"nonexistentcodename"}. perform_test skips properties the OS doesn't report, so the result contradicts itself:

  echo '{"codename":"nonexistentcodename"}' | dsc resource test -r Microsoft/OSInfo -f -
  ... "_inDesiredState":true},"inDesiredState":true,"differingProperties":["codename"]
  

Expected behavior

- The version tests skip operator cases when the version isn't numeric, or the resource handles non-numeric versions. An `=` operator could at least match literally.
- The codename tests are skipped when the OS has no codename.
- A desired `codename` (or other property) that the OS doesn't have is not in the desired state, consistent with `differingProperties`.

Actual behavior

5 failures in `resources/osinfo/tests/osinfo.tests.ps1` on Arch Linux: 3 version constraints and both codename tests.

Error details

Environment data

DSC 3.3.0 (release/v3.3, ea572fa), built from source on Arch Linux x86_64

Name                           Value
----                           -----
PSVersion                      7.6.9
PSEdition                      Core
GitCommitId                    7.6.9
OS                             Arch Linux
Platform                       Unix
PSCompatibleVersions           {1.0, 2.0, 3.0, 4.0…}
PSRemotingProtocolVersion      2.4
SerializationVersion           1.1.0.1
WSManStackVersion              3.0

Version

3.3.0

Visuals

No response