org-capture fails to insert link even on :immediate-finish templates

[Leo Gaspard]

Hello,

I have an org-capture template with :immediate-finish t. In
notmuch-mode, it looks like org-capture support is not implemented yet
for the search interfaces, and so when capturing on these interfaces
(without noticing), I get a capture without the link.

Is it possible to make org-capture fail loudly when capturing a
=:immediate-finish t= template for which all the substitutions didn't
succeed, instead of just having empty strings at the substitution
locations?

Thank you!
  Leo