SettingsManager::bootSettings - fix providing CIVICRM_DSN directly on Standalone

[ufundo]

Overview

On Standalone, the CIVICRM_DSN can be provided using env vars for its component parts. However the exceptional handling for this doesn't check whether the value for CIVICRM_DSN has actually come from component parts - and so tries to reset it if it is already set.

Before

On Standalone, set CIVICRM_DSN as env var

( ! ) Warning: Constant CIVICRM_DSN already defined in /home/ufundo/Code/civicrm/civicrm-buildkit/build/build-0/web/core/Civi/Core/SettingsManager.php on line 435

After

Setting CIVICRM_DSN as env var works as expected.

[civibot]

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[ufundo]

@michaelmcandrew I think you hit this the other day - could you review?

[michaelmcandrew]

@ufundo - I don't think I did actually. In #31155 (comment) I was able to pass in a DSN or seperate variables and it booted OK.

In any case, I applied your patch onto #31155 (comment) and can confirm that it still booted fine when db credentials were passed in as a DSN or as seperate variables.

And the cursory glance at the logic looks fine to me (though I have no knowledge of the rest of the context so not sure how helpful that is, but anyway).

[seamuslee001]

I'm just going to get Jenkins to run the standlone ones but I think this is mergeable

[ufundo]

thanks @seamuslee001

just noting standalone upgrade test fails are pre-existing