openApi.getServers() is null in OpenApiCustomiser when using different locales

[harsel]

Describe the bug

In an OpenApiCustomiser, calling OpenApi.getServers() may return null.

To Reproduce

• Using latest master
• Add a bean of type OpenApiCustomiser which invokes getServers()
• Request the open api document using header Accept-Language: en-US
• Request the open api document using header Accept-Language: de-DE
• The second request fails with a NullpointerException in the OpenApiCustomiser as openApi.getServers() returns null

[bnasslahsen]

@harsel,

Can you Provide a Minimal, Reproducible Example - with HelloController that reproduces the problem ?

[harsel]

I already created PR #2156 with a failing test.