Suppressed insertion of signature when it's nil.

[jeeger]

This way, not even the '--' lines are inserted. This is useful for having a signature in some
folders, but none in others.

[ikazuhiro]

Please show message such as "signature not found" when signature is nil at least when called interactively.

[ikazuhiro]

As far as I tested, signature never becomes nil unless I set mime-edit-default-signature to nil, which is unexpected setting. How do you reach such situation?

I can't remember details, but mime-edit-insert-signature seems to de designed always to insert signature. If you interactively call the function, it is assumed that your brain decides whether signature should be inserted. If you non-interactively call the function, wl-draft-config-alist provides such conditional calls. How is your actual usage?

[jeeger]

That's right. However, I want a configuration where I automatically insert a signature for some accounts, but not for others. Thus the modification. I hadn't thought of using wl-draft-config-alist for this, however, I'll have a look. Thanks for the pointer!