[Debconf-devel] Modify default value in template at runtime?

[Lukas Haemmerle]

Hi

Sorry if this is not the right place to ask but I haven't found a better
place to ask.

I would like to know if there is a solution for the following debconf
problem.

During configuration of the package, I want to ask the user 2 questions.
E.g. question 1: What is your hostname? The default value of question 2
shall depend on the value entered in question one. E.g. question 2:
Enter the webmaster email address of your host. The default value for
that second question shall be  webmaster@{ValueEnteredInQuestion1}

How can this be done and can it be done at all? I have spent about three
hours trying to figure this out.

The following approach with db_set question2
"webmaster@{ValueEnteredInQuestion1}" works only half.

db_input medium some-package/hostname || true
db_go || true
db_get ssome-package/hostname
hostname=$RET

db_set some-package/supportContact "webmaster@${hostname}"
db_input medium some-package/supportContact || true
db_go || true

The default value displayed in the default frontend indeed is
"webmaster@${hostname}", however when the user changes that value to
something completely different (e.g. "admin at some.other.host.com") this
entered value is ignored and "webmaster@${hostname}" is stored in
debconf... Numerous atempts with db_unregister and db_fset have failed.

So, is there a way to modify a default value displayed in the front-end
at runtime such that it is stored correctly in debconf even if the user
changes this presented default value to something else?


Best Regards
Lukas

-- 
Lukas Haemmerle
lukas at haemmerle.net