On 01/02/17 at 05:10pm, Stefan Klinger wrote:
Hi,
I'm providing a fix [1] for the following issue.
I've noticed that exactly one `Exec` directive is allowed in alpm-hooks(5). This is not explicitly stated in the manual (the word "required" does not usually imply "non-repeatable", as seems to be intended by the manual), nor does it rise an error. Instead, multiple occurrences are silently ignored.
Use case:
# When installed as a pacman hook [1], this will call the # `my-update-pacman-mirrorlist` script every time the file # `/etc/pacman.d/mirrorlist` should be updated.
[Trigger] Operation = Upgrade Operation = Install Type = File Target = etc/pacman.d/mirrorlist
[Action] When = PostTransaction Exec = /usr/bin/my-update-pacman-mirrorlist Exec = /usr/bin/rm -f /etc/pacman.d/mirrorlist.pacnew
Only the last `Exec` is used. I think it is semantically correct since the syntax looks like an assignment that overwrites the previous one. But it is inconsistent with the use of `Operation` in the `Trigger` section. I would expect the commands to be evaluated in order, or to see an error due to reusing `Exec`.
All options accept a single value unless the documentation says otherwise. For single-value options, using the last value is fairly standard. I'm not sure why you would expect hooks to behave any differently.
I think raising an error would be best, otherwise pacman would have to provide means to decide how to handle individually failing commands, a situation that is more flexibly handled by an external script, which should be called instead of using multiple `Exec`s.
I'm neutral on treating overwriting single-value options as an error. I'm generally in favor of being strict when parsing hooks, but I'm still considering allowing Include's in hooks, which would complicate this.
I have implemented this in [1] and added a test. If you like that, I would update the documentation, and also look for other values that are silently overwritten when parsing a hook. Also, I'd like to make `Operation` accept things like
Operation = Upgrade Install
and in future versions deprecate the current use of multiple assignments which I consider rather unfortunate.
Multiple "assignments" are not going away. Triggers can have multiple Targets and forcing people to cram them all on one line is a terrible idea. This is also how multi-value options in pacman's configuration are parsed.
Cheers, Stefan
____________________ [1] https://github.com/s5k6/pacman/tree/fix-hook-exec