Part 1, which addresses the issue for simple properties that have
a plain remove-by-value function.
Rationale:
Removing a value/index that does not exist should not be a failure.
Woule you like:
$ nmcli connection modify "$PROFILE" autoconnect no
$ nmcli connection modify "$PROFILE" autoconnect no
Error: autoconnect is already disabled
So, why would it be a good idea to fail during
$ nmcli connection modify "$PROFILE" -vpn.data ca
$ nmcli connection modify "$PROFILE" -vpn.data ca
Error: failed to remove a value from vpn.data: invalid option 'ca'.
Generally, it should not be an error to remove an option, as long
as the option itself is valid. For example,
$ nmcli connection modify "$PROFILE" -vlan.ingress-priority-map bogus
should fail, but
$ nmcli connection modify "$PROFILE" -vlan.ingress-priority-map 1:5
should succeed even if there was nothing to remove.
The same code is used by nmcli. Obviously, clients also need to
parse string representations.
That begs the question whether this should be public API of libnm.
Maybe, but don't decide that now, just reuse the code internally via
"shared/nm-libnm-core-utils.h".
We have code in "shared/nm-utils" which are general purpose
helpers, independent of "libnm", "libnm-core", "clients" and "src".
We have shared code like "shared/nm-ethtool-utils.h" and
"shared/nm-meta-setting.h", which is statically linked, shared
code that contains libnm related helpers. But these helpers already
have a specific use (e.g. they are related to ethtool or NMSetting
metadata).
Add a general purpose helper that:
- depends (and extends) libnm-core
- contains unrelated helpers
- can be shared (meaning it will be statically linked).
- this code can be used by any library user of "libnm.so"
(nmcli, nm-applet) and by "libnm-core" itself. Thus, "src/"
and "libnm/" may also use this code indirectly, via "libnm-core/".
