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@lzybkr Please take a look. I think you have been dealing with the iterations of this issue.

I tested these changes in an interactive session and it does not fix #2306, so it seems we assumed incorrectly that making -Message optional introduced that problem.

Did you want to investigate a fix for #2306 before we accept this PR?

Never mind about fixing #2306 - the fix is/will be in #2330.

Clear about #2306. I removed Close #2306.

Did you want to investigate a fix for #2306 before we accept this PR?

I believe that this PR #2315 must be accepted before #2330, because in #2330 already added tests (for "It "Get-Credential without parameters" { " and so on) - @daxian-dbw made unnecessary work.

I update fist comment of the PR with arguments.

I tried the changes made by @daxian-dbw - I think it provides exactly the experience we want without making -Message mandatory.

Having a mandatory parameter in a parameter set is a guideline, not a requirement. In this specific case, there are benefits to not making -Message mandatory - one can pass a custom -Title and use the default localized message.

And correct me if I'm wrong, but are there really compatibility issues? All previous versions of PowerShell support calling Get-Credential with no parameters, #2330 just improves the user experience.

I revoke "compatibility" statement. In previous versions, an user only receives one more question, but a script will work.

Having a mandatory parameter in a parameter set is a guideline, not a requirement

Yes, it is not a requirement but the guide says about best practice for script writer that comes from the best user experience.

But! I was very conservative. I modeled various combinations of parameters (default and non-default, localized and non-localized) and think that as best practice the script writers will have to specify the message and title in a pair without the requirement that message is mandatory.

So you can dicard the PR. @lzybkr thanks for great discussion!

Thanks @iSazonov - I really appreciate your attention to details like this, hopefully we'll see more contributions from you in the future.