Incomplete bitbucket-server user with empty email string results in invalid gitAuthor

[rarkins]

Discussed in #31174

^{Originally posted by Kiskae September 3, 2024}

What would you like help with?

I think I found a bug

How are you running Renovate?

Self-hosted

If you're self-hosting Renovate, tell us which platform (GitHub, GitLab, etc) and which version of Renovate.

bitbucket-server, renovate 38.52.2

Please tell us more about your question or problem

Unable to provide a reproduction since it involves just the platform integration.

Root cause appears to be this change: #29525

I've traced it to the fact that the bitbucket server account linked to the renovate token does not have an email address configured, this causes the change above to set the gitAuthor to a value without an email and triggers the validation error later on.

Essentially the value emailAddress in the following line can be an empty string:
https://github.com/amezin/renovate/blob/745978f11ffbc2585be20f005fdbe854b19b466c/lib/modules/platform/bitbucket-server/index.ts#L151

Logs (if relevant)

Logs

[2024-09-03T07:17:48.267Z]          "validationSource": "None",
[2024-09-03T07:17:48.267Z]          "validationError": "Invalid gitAuthor",
[2024-09-03T07:17:48.267Z]          "validationMessage": "`gitAuthor` is not parsed as valid RFC5322 format: `******* <>`",
[2024-09-03T07:17:48.267Z]          "message": "config-validation",