add update-repos script, actually merge all the repos

Author: jpolitz

util/update-repos.sh

@@ -0,0 +1,59 @@
+#!/bin/zsh
+
+# For each subrepo branch, pulls in any new commits from the upstream remote.
+# Then merges any updated branches back into the current branch.
+
+typeset -A repos=(
+  ["embed"]="git@github.com:jpolitz/pyret-embed.git"
+  ["vscode"]="git@github.com:jpolitz/pyret-parley-vscode.git"
+  ["npm"]="git@github.com:brownplt/pyret-npm.git"
+  ["pyret.org"]="git@github.com:brownplt/pyret.org.git"
+  ["docs"]="git@github.com:brownplt/pyret-docs.git"
+  ["codemirror-mode"]="git@github.com:brownplt/pyret-codemirror-mode.git"
+  ["code.pyret.org"]="git@github.com:brownplt/code.pyret.org.git"
+  ["lang"]="git@github.com:brownplt/pyret-lang.git"
+)
+
+set -e
+
+start_branch=$(git rev-parse --abbrev-ref HEAD)
+updated=()
+
+# Return to the starting branch on exit (covers both success and error paths).
+# If a merge conflict left us in MERGING state, abort it first so checkout works.
+cleanup() {
+  local git_dir
+  git_dir=$(git rev-parse --git-dir 2>/dev/null) || return
+  if [[ -f "$git_dir/MERGE_HEAD" ]]; then
+    echo "Aborting in-progress merge..."
+    git merge --abort
+  fi
+  git checkout "$start_branch"
+}
+trap cleanup EXIT
+
+for branch in "${(@k)repos}"; do
+  upstream="${repos[$branch]}"
+  git checkout "$branch"
+  before=$(git rev-parse HEAD)
+
+  echo "==> Checking $branch ($upstream)"
+  git pull --no-ff "$upstream"
+
+  after=$(git rev-parse HEAD)
+  updated+=("$branch")
+done
+
+# Back to start before merging (trap will fire on EXIT but we do it explicitly
+# here so the merges happen on the right branch)
+trap - EXIT
+git checkout "$start_branch"
+
+echo ""
+echo "==> Merging updated branches: ${updated[*]}"
+for branch in "${updated[@]}"; do
+  git merge --no-ff "$branch" -m "Merge branch '$branch'"
+done
+
+echo ""
+echo "Done."