[pacman-dev] So many HOOK puns could go here!

[Andrew Gregory]

On 07/06/13 at 01:08am, Allan McRae wrote:
> 
> 
> Looking at the ini parsing patch yesterday motivated me to get hooks
> implemented.  But first we need to completely flesh out the details.
> This is too complex of a change to make up as we go along.
> 
> >From the mention of the previous patch, you should be able to figure out
> the format I am pushing...
> 
> Look here:
> https://wiki.archlinux.org/index.php/User:Allan/Pacman_Hooks
> 
> 
> Questions to answer:
> 
> 1) Should hooks have a defined suffix.
> PRO: Avoids .pac{save,new} conflicts
> CON: There should be none (adjustments made in /etc)
> 

I would vote for a suffix just as a precaution.

> 
> 2) Complete list of when hooks can be run.  Current list:
> 
> PreRemove
> PostRemove
> PreInstall
> PostInstall
> Transaction
> 
> I guess we should add Pre/Post suffix to Transaction for generality.
> Any more needed?
> 
> 
> 3) Trigger.  In the wiki I have "File" and "Package" to specify
> triggers, allowing wildcards.  These can be suffixed with
> Install/Upgrade/Removal.  Note that any operation can be triggered by
> using e.g "PackageInstall = *".   Does that seem general enough?
> 

There is some redundancy here.  Do we need Install/Remove/Upgrade in
both the "when" and the trigger?

> 
> 4) Should File hooks run immediately after the file or at the end of the
> package.   At the end of the package fits in with out current install
> scripts ad so would be easier to implement.  Can anyone think of a
> situation with directly after the file is preferable?
> 

I think all of the "when"s should mean the same thing whether the
trigger is a file or a package.  If we discover we need hooks that run
immediately after a file is modified we should add a separate "when"
for that.

> 
> 5) How should we handle packages installing a new hook?   e.g. In Arch,
> texinfo will carry the install-info hook.  I think it will still need a
> post_install script to add all the info files installed before texinfo
> was to the info directory, but then the hook install should be
> recognised and act on any packages installed after that.  Reasonable?
> 

I think hooks have to be immediately recognized as you describe.
Otherwise, it seems like it would be difficult to ever transition from
using an install script to a hook.

> 
> 6) Any other comments?
> 

Hooks have the potential to replace install scripts altogether; is
that the intent or do you just want to supplement them?

> 
> My plan is:
> 1) Finalise format (and I will make executive decisions here if
> bikeshedding occurs...)
> 2) Get the ini parsing patches into shape
> 3) Get the parsing of hook files occuring
> 4) Get transaction based hooks running
> 5) Get pre/post file/package install hooks running
> 
> Allan