snapcraft: hardcode support for compopt to fix bash completion

[simondeziel]

@kadinsayani found that when executed by snapd, the compopt support detection was broken.

[simondeziel]

@kadinsayani here's what I've checked so far:

lxc completion bash > /tmp/orig
lxc completion bash | sed "$MONSTRUOSITY" > /tmp/new-inline

Which gives this minimal diff:

$ diff -Naur /tmp/orig /tmp/new-inline 
--- /tmp/orig	2024-11-21 20:24:06.523373035 -0500
+++ /tmp/new-inline	2024-11-21 20:42:49.076393122 -0500
@@ -23,7 +23,7 @@
     # Prepare the command to request completions for the program.
     # Calling ${words[0]} instead of directly lxc allows handling aliases
     args=("${words[@]:1}")
-    requestComp="${words[0]} __complete ${args[*]}"
+    requestComp="/snap/lxd/current/bin/lxc __complete ${args[*]}"
 
     lastParam=${words[$((${#words[@]}-1))]}
     lastChar=${lastParam:$((${#lastParam}-1)):1}
@@ -269,7 +269,7 @@
             desc=${comp#*$tab}
             comp=${comp%%$tab*}
 
-            # $COLUMNS stores the current shell width.
+            COLUMN="$(tput cols)"  # store the current shell width.
             # Remove an extra 4 because we add 2 spaces and 2 parentheses.
             maxdesclength=$(( COLUMNS - longest - 4 ))
 
@@ -330,9 +330,9 @@
 }
 
 if [[ "builtin" = "builtin" ]]; then
-    complete -o default -F __start_lxc lxc
+    complete -o default -F __start_lxc lxd.lxc lxc
 else
-    complete -o default -o nospace -F __start_lxc lxc
+    complete -o default -o nospace -F __start_lxc lxd.lxc lxc
 fi
 
 # ex: ts=4 sw=4 et filetype=sh

[kadinsayani]

I'm yet to test this with a snapcraft build but LGTM!

[tomponline]

@kadinsayani @simondeziel there appears to be two different proposals for the CLI completion, this PR and #629

which one is the preferred approach?

[simondeziel]

Dunno about the preferred way but I just tested this one and it works:

$ sudo snap install --dangerous lxd_0+git.55c4560d_amd64.snap
[sudo] password for sdeziel: 
2024-11-22T09:07:12-05:00 INFO Waiting for "snap.lxd.daemon.service" to stop.
lxd 0+git.55c4560d installed

$ sudo snap alias lxd.lxc lxc

$ lxc storage volume copy d<tab>
$ lxc storage volume copy default/  # autocompleted without any trailing " ", yay!

[kadinsayani]

Dunno about the preferred way but I just tested this one and it works:

$ sudo snap install --dangerous lxd_0+git.55c4560d_amd64.snap
[sudo] password for sdeziel: 
2024-11-22T09:07:12-05:00 INFO Waiting for "snap.lxd.daemon.service" to stop.
lxd 0+git.55c4560d installed

$ sudo snap alias lxd.lxc lxc

$ lxc storage volume copy d<tab>
$ lxc storage volume copy default/  # autocompleted without any trailing " ", yay!

Amazing 🎉

[kadinsayani]

@kadinsayani @simondeziel there appears to be two different proposals for the CLI completion, this PR and #629

which one is the preferred approach?

Let's go with Simon's approach, and keep the other potential solutions in mind if we face further issues with snapd's completion handling. For reference: canonical/lxd#14506. Another approach is to create our own completion command; also see https://github.com/spf13/cobra/blob/02326d52c0704d79169819698693b0698e748f55/bash_completionsV2.go.