templates/hooks--push-to-checkout.sample

   1 #!/bin/sh
   2
   3 # An example hook script to update a checked-out tree on a git push.
   4 #
   5 # This hook is invoked by git-receive-pack(1) when it reacts to git
   6 # push and updates reference(s) in its repository, and when the push
   7 # tries to update the branch that is currently checked out and the
   8 # receive.denyCurrentBranch configuration variable is set to
   9 # updateInstead.
  10 #
  11 # By default, such a push is refused if the working tree and the index
  12 # of the remote repository has any difference from the currently
  13 # checked out commit; when both the working tree and the index match
  14 # the current commit, they are updated to match the newly pushed tip
  15 # of the branch. This hook is to be used to override the default
  16 # behaviour; however the code below reimplements the default behaviour
  17 # as a starting point for convenient modification.
  18 #
  19 # The hook receives the commit with which the tip of the current
  20 # branch is going to be updated:
  21 commit=$1
  22
  23 # It can exit with a non-zero status to refuse the push (when it does
  24 # so, it must not modify the index or the working tree).
  25 die () {
  26         echo >&2 "$*"
  27         exit 1
  28 }
  29
  30 # Or it can make any necessary changes to the working tree and to the
  31 # index to bring them to the desired state when the tip of the current
  32 # branch is updated to the new commit, and exit with a zero status.
  33 #
  34 # For example, the hook can simply run git read-tree -u -m HEAD "$1"
  35 # in order to emulate git fetch that is run in the reverse direction
  36 # with git push, as the two-tree form of git read-tree -u -m is
  37 # essentially the same as git switch or git checkout that switches
  38 # branches while keeping the local changes in the working tree that do
  39 # not interfere with the difference between the branches.
  40
  41 # The below is a more-or-less exact translation to shell of the C code
  42 # for the default behaviour for git's push-to-checkout hook defined in
  43 # the push_to_deploy() function in builtin/receive-pack.c.
  44 #
  45 # Note that the hook will be executed from the repository directory,
  46 # not from the working tree, so if you want to perform operations on
  47 # the working tree, you will have to adapt your code accordingly, e.g.
  48 # by adding "cd .." or using relative paths.
  49
  50 if ! git update-index -q --ignore-submodules --refresh
  51 then
  52         die "Up-to-date check failed"
  53 fi
  54
  55 if ! git diff-files --quiet --ignore-submodules --
  56 then
  57         die "Working directory has unstaged changes"
  58 fi
  59
  60 # This is a rough translation of:
  61 #
  62 #   head_has_history() ? "HEAD" : EMPTY_TREE_SHA1_HEX
  63 if git cat-file -e HEAD 2>/dev/null
  64 then
  65         head=HEAD
  66 else
  67         head=$(git hash-object -t tree --stdin </dev/null)
  68 fi
  69
  70 if ! git diff-index --quiet --cached --ignore-submodules $head --
  71 then
  72         die "Working directory has staged changes"
  73 fi
  74
  75 if ! git read-tree -u -m "$commit"
  76 then
  77         die "Could not update working tree to new HEAD"
  78 fi