cg-admin-uncommit

   1 #!/usr/bin/env bash
   2 #
   3 # Undo a commit or a series of commits
   4 # Copyright (c) Matt Porter, 2005
   5 # Copyright (c) Petr Baudis, 2005
   6 #
   7 # Takes a commit ID which is the earliest commit to be removed from
   8 # the repository. If no parameter is passed, it uncommits the latest
   9 # commit ('HEAD'). Read the CAVEATS section before using it for the
  10 # first time.
  11 #
  12 # This command is a close relative of `cg-switch -f` (which does
  13 # essentially the same thing, but is slightly more powerful at the
  14 # expense of a more elaborate usage). Do not confuse either with the
  15 # operation performed by `cg-seek`, which is meant only for temporary
  16 # excursions to the project history.
  17 #
  18 # OPTIONS
  19 # -------
  20 # -t:: Restore the working copy of the previous commit
  21 #       This optional parameter makes `cg-admin-uncommit` to roll back
  22 #       the tree as well to the previous commit. Without this option
  23 #       (by default) 'Cogito' keeps the tree in its current state,
  24 #       therefore generating tree with local changes against the target
  25 #       commit, consisting of the changes in the rolled back commits.
  26 #
  27 # CAVEATS
  28 # -------
  29 # This command can be dangerous! It is safe to do as long as you do not
  30 # push the commit out in the meantime, but you should 'NEVER' uncommit an
  31 # already pushed out commit. Things will break for the fetchers since you
  32 # just broke the fast-forward merging mechanism (the new commit is not
  33 # descendant of the previous one), and the push command will refuse to
  34 # push again after you uncommitted a pushed out commit, too. At the moment
  35 # you pushed the commit out it's etched to the history, live with that.
  36
  37 # Testsuite: Marginal (part of t9210-update)
  38
  39 USAGE="cg-admin-uncommit [-t] [COMMIT_ID]"
  40 _git_requires_root=1
  41
  42 . "${COGITO_LIB}"cg-Xlib || exit 1
  43
  44 [ -s "$_git/blocked" ] && die "uncommitting blocked: $("cat $_git/blocked")"
  45
  46 rollback_tree=
  47 while optparse; do
  48         if optparse -t; then
  49                 rollback_tree=1
  50         else
  51                 optfail
  52         fi
  53 done
  54
  55
  56 base="$(cg-object-id -c)" || exit 1
  57
  58 commit="$(cg-object-id -c "${ARGS[0]}")" || exit 1
  59 [ "$(git-rev-list $commit ^$base)" ] && \
  60         die "$commit: not an ancestor of HEAD"
  61
  62 parent="$(cg-object-id -p "$commit")" || exit 1
  63 [ "$parent" ] || die "cannot rewind behind the initial commit"
  64 [ "$(echo "$parent" | wc -l)" -gt 1 ] &&
  65         die "cannot rewind merges; please 'cg-switch -f -r parentid $_git_head' instead"
  66
  67
  68 echo "Rewinding $base (HEAD) -> $parent" >&2
  69
  70 tree_timewarp "backwards" "$rollback_tree" "$base" "$parent"