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    cli: rework printing of `nmcli connection` for multiple active connections · a1b25a47
    Thomas Haller authored
    The output of `nmcli connection show` contains also information about
    whether the profile is currently active, for example the device and
    the current (activation) state.
    
    Even when a profile can be activated only once (without supporting
    mutiple activations at the same time), there are moments when a
    connection is activating and still deactivating on another device.
    NetworkManager ensures in the case with single activations that
    a profile cannot be in state "activated" multiple times. But that
    doesn't mean, that one profile cannot have multiple active connection
    which reference it. That was already handled wrongly before, because
    `nmcli connection show` would only search the first matching
    active-connection. That is, it would arbitrarily pick an active
    connection in case there were multiple and only show activation
    state about one.
    Furthermore, we will soon also add the possibility, that a profile can be
    active multiple times (at the same time). Especially then, we need to
    extend the output format to show all the devices on which the profile is
    currently active.
    
    Rework printing the connection list to use nmc_print(), and fix various
    issues.
    
    - as discussed, a profile may have multiple active connections at each time.
      There are only two possibilities: if a profile is active multiple
      times, show a line for each activation, or otherwise, show the
      information about multiple activations combined in one line, e.g. by
      printing "DEVICE eth0,eth1". This patch, does the former.
      We will now print a line for each active connection, to show
      all the devices and activation states in multiple lines.
      Yes, this may result in the same profile being printed multiple times.
      That is a change in behavior, and inconvenient if you do something
      like
    
         for UUID in $(nmcli connection show | awk '{print$2}'); do ...
    
      However, above is anyway wrong because it assumes that there are no
      spaces in the connection name. The proper way to do this is like
    
         for UUID in $(nmcli -g UUID connection show); do ...
    
      In the latter case, whenever a user selects a subset of fields
      (--fields, --get) which don't print information about active connections,
      these multiple lines are combined. So, above still works as expected,
      never returning duplicate UUIDs.
    
    - if a user has no permissions to see a connection, we previously
      would print "<invisible> $NAME". No longer do this but just print
      the ID was it is reported by the active-connection. If the goal
      of this was to prevent users from accidentally access the non-existing
      connection by $NAME, then this was a bad solution, because a script
      would instead try to access "<invisible> $NAME". This is now solved
      better by hiding the active connection if the user selects "-g NAME".
    
    - the --order option now sorts according to how the fields are shown.
      For example, with --terse mode, it will evaluate type "802-11-wireless"
      but with pretty mode it will consider "wifi". This may change the
      ordering in which connections are shown. Also, for sorting the name,
      we use g_utf8_collate() because it's unicode.
    a1b25a47