bin/update-buildable-branch: New utility for `buildable' branches.

I'm experimentally publishing semiautomatically-maintained branches of
projects with all of the build tools and other stuff included.

diff --git a/bin/update-buildable-branch b/bin/update-buildable-branch
new file mode 100755 (executable)
index 0000000..b7f71ff
--- /dev/null
+++ b/bin/update-buildable-branch
@@ -0,0 +1,110 @@
+#! /bin/sh -e
+
+fail () {
+  echo >&2 "$0: $*"
+  exit 1
+}
+
+usage () {
+  echo "usage: $0 [-c] [UPSTREAM BUILDABLE]"
+}
+
+fail_usage () {
+  usage >&2
+  exit 1
+}
+
+## Parse the command-line.
+bogusp=nil createp=nil
+unset head new
+while getopts "ch" opt; do
+  case $opt in
+    h) usage; exit 0 ;;
+    c) createp=t ;;
+    *) bogusp=t ;;
+  esac
+done
+shift $(( $OPTIND - 1 ))
+case $# in 0) ;; 1) bogusp=t ;; *) head=$1 new=$2; shift 2 ;; esac
+case $# in 0) ;; *) bogusp=t ;; esac
+case $bogusp in nil) ;; *) fail_usage ;; esac
+
+## Get the current branch name.
+case ${head+t} in
+  t) ;;
+  *)
+    head=$(git symbolic-ref HEAD)
+    case $head in
+      refs/heads/*) head=${head#refs/heads/} ;;
+      *) fail "HEAD is not at a branch head" ;;
+    esac
+    case $head in
+      buildable/*) fail "upstream is already a buildable branch" ;;
+    esac
+    ;;
+esac
+
+## Get the output branch name.
+case ${new+t} in
+  t) ;;
+  *)
+    new=buildable/$head
+    ;;
+esac
+case $createp in
+  t)
+    if git rev-parse $new -- >/dev/null 2>&1; then
+      fail "branch $new already exists"
+    fi
+    old=0000000000000000000000000000000000000000
+    ;;
+  nil)
+    old=$(git rev-parse $new --)
+    ;;
+esac
+
+## Make a temporary place.
+git=$(git rev-parse --git-dir)
+git=$(cd $git && pwd)
+dir=$(mktemp -d)
+trap "cd; rm -rf \"$dir\"" EXIT INT TERM
+cd "$dir"
+mkdir work tmp
+
+## Make a nice clean checkout.
+GIT_INDEX_FILE=$dir/idx; export GIT_INDEX_FILE
+GIT_DIR=$git; export GIT_DIR
+GIT_WORK_TREE=$dir/work; export GIT_WORK_TREE
+git read-tree "$head^{}"
+git checkout-index --all
+
+## Go in, and set stuff up.  The business with `RELEASE' is kinda scungy.
+## Sorry 'bout that.
+cd work
+if ! ver=$(git describe --abbrev=4 "$head^{}" 2>/dev/null); then
+  ver=UNKNOWN
+fi
+echo "$ver" >RELEASE
+mdw-setup
+rm -rf autom4te.cache/ RELEASE
+
+## Pick through newly added symlinks and snap them to real files.
+git ls-files -o | while read f; do
+  if [ -L "$f" ]; then
+    cp "$f" ../tmp/snap
+    mv ../tmp/snap "$f"
+  fi
+done
+
+## Add the new files to the tree.
+commit () {
+  tree=$1; shift
+  case $createp in
+    t) git commit-tree -p "$head^{}" "$@" $tree ;;
+    nil) git commit-tree -p "$new" -p "$head^{}" "$@" $tree ;;
+  esac
+}
+git ls-files -oz | xargs -0r git add -f
+tree=$(git write-tree)
+commit=$(commit $tree -m "Update automatically managed build utilities.")
+git update-ref "refs/heads/$new" $commit $old

diff --git a/setup b/setup
index 6504cbb..004b9fd 100755 (executable)
--- a/setup
+++ b/setup
@@ -258,6 +258,7 @@ scripts="
   mdw-pager
   mdw-conf
   mdw-build
+  update-buildable-branch
   emacsclient-hack
   movemail-hack
   sendmail-hack