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
  79