Remove snapshot unit type

Snapshots were never useful or used for anything. Many systemd
developers that I spoke to at systemd.conf2015, didn't even know they
existed, so it is fairly safe to assume that this type can be deleted
without harm.

The fundamental problem with snapshots is that the state of the system
is dynamic, devices come and go, users log in and out, timers fire...
and restoring all units to some state from the past would "undo"
those changes, which isn't really possible.

Tested by creating a snapshot, running the new binary, and checking
that the transition did not cause errors, and the snapshot is gone,
and snapshots cannot be created anymore.

New systemctl says:
Unknown operation snapshot.
Old systemctl says:
Failed to create snapshot: Support for snapshots has been removed.

IgnoreOnSnaphost settings are warned about and ignored:
Support for option IgnoreOnSnapshot= has been removed and it is ignored

http://lists.freedesktop.org/archives/systemd-devel/2015-November/034872.html

1 files changed, 1 insertions, 7 deletions

diff --git a/shell-completion/bash/systemctl.in b/shell-completion/bash/systemctl.in
index f9a4f2265..d80d8f02a 100644
--- a/shell-completion/bash/systemctl.in
+++ b/shell-completion/bash/systemctl.in
@@ -174,14 +174,12 @@ _systemctl () {
          [TARGET_AND_UNITS]='add-wants add-requires'
              [MASKED_UNITS]='unmask'
                      [JOBS]='cancel'
-                [SNAPSHOTS]='delete'
                      [ENVS]='set-environment unset-environment'
                [STANDALONE]='daemon-reexec daemon-reload default
                              emergency exit halt hibernate hybrid-sleep kexec list-jobs
                              list-sockets list-timers list-units list-unit-files poweroff
                              reboot rescue show-environment suspend get-default
                              is-system-running'
-                     [NAME]='snapshot'
                      [FILE]='link switch-root'
                   [TARGETS]='set-default'
         )
@@ -259,16 +257,12 @@ _systemctl () {
                 fi
                 compopt -o filenames
 
-        elif __contains_word "$verb" ${VERBS[STANDALONE]} ${VERBS[NAME]}; then
+        elif __contains_word "$verb" ${VERBS[STANDALONE]}; then
                 comps=''
 
         elif __contains_word "$verb" ${VERBS[JOBS]}; then
                 comps=$( __systemctl $mode list-jobs | { while read -r a b; do echo " $a"; done; } )
 
-        elif __contains_word "$verb" ${VERBS[SNAPSHOTS]}; then
-                comps=$( __systemctl $mode list-units --type snapshot --full --all \
-                        | { while read -r a b; do echo " $a"; done; } )
-
         elif __contains_word "$verb" ${VERBS[ENVS]}; then
                 comps=$( __systemctl $mode show-environment \
                     | while read -r line; do echo " ${line%%=*}=";done )