mhwd-kernel -i only works when you boot with a Manjaro kernel

[eugen-manjaro]

Hello @philmmanjaro !
I found out that if I boot with a non-Manjaro kernel I cannont install a Manjaro kernel with mhwd-kernel -i

~ >>> mhwd-kernel -li                                                          
Currently running: 4.15.18-1-ck (linux415)
The following kernels are installed in your system:
   * linux414
~ >>> sudo mhwd-kernel -i linux417                                             
:: Synchronizing package databases...
 core                     143.4 KiB   567K/s 00:00 [######################] 100%
 extra                   1723.2 KiB   690K/s 00:02 [######################] 100%
 community                  4.6 MiB   690K/s 00:07 [######################] 100%
 multilib                 178.2 KiB   696K/s 00:00 [######################] 100%
error: no targets specified (use -h for help)
~ >>>                                       

If I boot with a Manjaro kernel I'm able to install with mhwd-kernel -i

eugen@mjro Linux 4.17.0-1-MANJARO x86_64 Tue Apr 24 12:31:26 CEST 2018
~ >>> sudo mhwd-kernel -i linux414                                             
[sudo] password for eugen: 
:: Synchronizing package databases...
 core                     143.4 KiB   223K/s 00:01 [######################] 100%
 extra                   1723.0 KiB   267K/s 00:06 [######################] 100%
 community                  4.6 MiB   281K/s 00:17 [######################] 100%
 multilib                 178.2 KiB   326K/s 00:01 [######################] 100%
resolving dependencies...
looking for conflicting packages...

Packages (2) linux414-4.14.35-1  linux414-headers-4.14.35-1

Total Installed Size:  161.68 MiB

:: Proceed with installation? [Y/n] 

Request: I think a notification which makes the user understand that they should boot with a Manjaro kernel would be nice if the check for running a Manjaro kernel fails.

@FadeMind pointed at this line:
https://github.com/manjaro/mhwd/blob/master/scripts/mhwd-kernel#L86

The forum discussion was here.

[FadeMind]

Hard coded 👨‍💻

pacman -Qqs "^linux[0-9][0-9]?([0-9])$" | while read -r; do echo "   * $REPLY"; done
pacman -Qqs "^linux[0-9][0-9]?([0-9])-rt$" | while read -r; do echo "   * $REPLY"; done

[[ $kernel != linux[0-9][0-9]?([0-9]) && $kernel != linux[0-9][0-9]?([0-9])-rt ]] && err "Please enter a valid kernel name.\n$(kernel_list)"
[[ $current = $kernel ]] && err "You can't remove your current kernel."

And here LOGIC just looking for Manjaro's scheme linuxNN-rt, When it found another scheme (linux-ck, linux-ck-ivybridge, linux-pf and so on), then error appear.

[philmmanjaro]

It is wanted like this as we have our extramodules automatically installed. Custom kernels most likely don't support pre-compiled extramodules.