RFE: file trigger scriptlet arguments

[pmatilai]

Splitting this from #2655 as this is a clearly separate thing that should be doable without massive redesign of the whole thing:

• First argument should reflect the triggered package count
• Non-trans scriptlets have should get a second argument reflecting the triggering package count

[dmnks]

* Non-trans scriptlets have should get a second argument reflecting the triggering package count

I wonder if we want the triggering package count (arg2) to be an aggregate count of all the triggering packages or just that of the first match?

There's a subtle difference in the semantics between regular triggers and file triggers in the way they are fired. A regular trigger can only ever be triggered by one package (e.g. %triggerin -- foo, bar, baz means "fire if any of these packages is installed"), whereas a file trigger can be triggered by multiple packages (e.g. %filetriggerin -- /etc/foo.d means "fire if any file with such a prefix is installed, regardless of which package it belongs to").

In both cases, the trigger only executes once, however the semantics of "which package triggered it" differs. Therefore, for regular triggers, arg2 is straightforward (it's always the count of the triggering package), however for file triggers, it's not.

As an example, consider the following scenario:

# bar.spec:
%filetriggerin -- /etc/foo.d

# foo.spec:
%files
/etc/foo.d/foo.conf

# baz.spec:
%files
/etc/foo.d/baz.conf

If bar is installed first, installing foo or baz afterwards results in the trigger being run once for each of those, so the triggering count (arg2) is straighforward (same as with regular triggers).

However, if foo and baz are installed first, installing bar afterwards results in the trigger being run once for both of those (with both filenames served via stdin), so the trigerring count (arg2) is now ambiguous - it can either be the count of foo or baz, or it can be the sum of both.

My take: The count should be an aggregate since that enables a file trigger script to detect when all the files subject to the prefix are being removed (which is one of the purposes of the arguments, also for regular triggers, in the first place).

Any thoughts?

[pmatilai]

Aggregate is what I thought of when writing the description, I don't see anything else making much sense. But, it's not like I've given this any deep meditation. Usefulness is all that matters for the arguments, otherwise we could just as well not bother 😅

[dmnks]

Thanks, the part about usefulness is actually on point 😄 That said, I haven't given it too much thought either, this is just the most obvious solution that comes to mind. I'll ponder about it a bit more but there's probably not much to ponder about anyway.