Add Opal version validation helper when checking backend connections

[villegar]

Summary

When using Opal as the backend, {dsROCrate} should include a helper function to validate the running Opal version as part of connection validation (see validate_opal_con).

This is important because Opal v5.7.2 introduced a change allowing AUDIT_ALL users read-only access to the /system/permissions API endpoint. This endpoint can be used to verify whether a user has audit rights (and similarly admin rights).

Without checking the Opal version, downstream functionality that depends on this endpoint may fail unexpectedly on older Opal instances.

Current behaviour

An Opal connection object can be created using opalr::opal.login():

con_auditor <- opalr::opal.login(
  username = "auditor",
  password = USERPASS,
  url = SERVER
)

The running Opal version is available via:

con_auditor$version

which returns the server version as a string.

Currently there does not appear to be a dedicated validation step ensuring the connected Opal server supports the required API behaviour.

Proposed enhancement

Add a helper function that:

1. Detects whether the backend is Opal
2. Retrieves the server version from the connection object
3. Verifies the version is compatible with the required permissions endpoint behaviour
4. Integrates this validation into existing connection checks

For example, compatibility checks could ensure the server version is >= 5.7.2.

Motivation

This would:

• Prevent runtime failures when permission checks rely on /system/permissions
• Provide clearer error messages for unsupported Opal versions
• Centralise backend capability validation logic
• Improve robustness of audit/admin permission verification workflows

Possible implementation ideas

Potential approaches include:

• A utility such as:

check_opal_version <- function(con, minimum = "5.7.2") {
  utils::compareVersion(con$version, minimum) >= 0
}

• Integrating the version validation into existing connection validation helpers
• Returning informative warnings/errors when unsupported versions are detected

Additional context

Support for read-only access to /system/permissions for AUDIT_ALL users was originally requested in Opal issue #4150:

• [Issue #4150: Add read access to /system/permissions for AUDIT_ALL users](Enable AUDIT_ALL users to read system permissions obiba/opal#4150)

The change was implemented and the issue closed via:

• [Pull Request #4151](fix: user with system audit permissions can read all system permissions obiba/opal#4151)

Since this behaviour is only available starting from Opal v5.7.2, {dsROCrate} should validate the connected Opal version before relying on this endpoint for audit/admin permission verification.

[villegar]

Fixed by 4d0f43727f44bd08caeb15188ef207f49bd38511