improve merge-pr script

The script now performs many more checks and reports errors in
a more intelligible way.

1 files changed, 133 insertions, 26 deletions

diff --git a/dev/tools/merge-pr.sh b/dev/tools/merge-pr.sh
index 9f24960ff..2f6f1af54 100755
--- a/dev/tools/merge-pr.sh
+++ b/dev/tools/merge-pr.sh
@@ -1,50 +1,157 @@
 #!/usr/bin/env bash
 
 set -e
+set -o pipefail
+
+API=https://api.github.com/repos/coq/coq
+OFFICIAL_REMOTE_URL="git@github.com:coq/coq"
 
 # This script depends (at least) on git and jq.
 # It should be used like this: dev/tools/merge-pr.sh /PR number/
 
-#TODO: check arguments and show usage if relevant
+RED="\033[31m"
+RESET="\033[0m"
+GREEN="\033[32m"
+BLUE="\033[34m"
+YELLOW="\033[33m"
+info() {
+  echo -e "${GREEN}info:${RESET} $1 ${RESET}"
+}
+error() {
+  echo -e "${RED}error:${RESET} $1 ${RESET}"
+}
+warning() {
+  echo -e "${YELLOW}warning:${RESET} $1 ${RESET}"
+}
 
-PR=$1
+check_util() {
+if ! command -v "$1" > /dev/null 2>&1; then
+  error "this script requires the $1 command line utility"
+  exit 1
+fi
+}
 
-CURRENT_LOCAL_BRANCH=$(git rev-parse --abbrev-ref HEAD)
-REMOTE=$(git config --get "branch.$CURRENT_LOCAL_BRANCH.remote")
-git fetch "$REMOTE" "refs/pull/$PR/head"
+ask_confirmation() {
+  read -p "Continue anyway? [y/N] " -n 1 -r
+  echo
+  if [[ ! $REPLY =~ ^[Yy]$ ]]
+  then
+    exit 1
+  fi
+}
 
-API=https://api.github.com/repos/coq/coq
+check_util jq
+check_util curl
+check_util git
+check_util gpg
+
+# command line parsing
+
+if [ $# != 1 ]; then
+  error "usage: $0 PR-number"
+  exit 1
+fi
+
+if [[ "$1" =~ ^[1-9][0-9]*$ ]]; then
+  PR=$1
+else
+  error "$1 is not a number"
+  exit 1
+fi
+
+# Fetching PR metadata
+
+TITLE=$(curl -s "$API/pulls/$PR" | jq -r '.title')
+info "title for PR $PR is ${BLUE}$TITLE"
 
 BASE_BRANCH=$(curl -s "$API/pulls/$PR" | jq -r '.base.label')
+info "PR $PR targets branch ${BLUE}$BASE_BRANCH"
+
+CURRENT_LOCAL_BRANCH=$(git rev-parse --abbrev-ref HEAD)
+info "you are merging in ${BLUE}$CURRENT_LOCAL_BRANCH"
 
+REMOTE=$(git config --get "branch.$CURRENT_LOCAL_BRANCH.remote")
+if [ -z "$REMOTE" ]; then
+  error "branch ${BLUE}$CURRENT_LOCAL_BRANCH${RESET} has not associated remote"
+  error "don't know where to fetch the PR from"
+  error "please run: git branch --set-upstream-to=THE_REMOTE/$CURRENT_LOCAL_BRANCH"
+  exit 1
+fi
+REMOTE_URL=$(git remote get-url "$REMOTE" --push)
+if [ "$REMOTE_URL" != "$OFFICIAL_REMOTE_URL" -a \
+     "$REMOTE_URL" != "$OFFICIAL_REMOTE_URL.git" ]; then
+  error "remote ${BLUE}$REMOTE${RESET} does not point to the official Coq repo"
+  error "that is ${BLUE}$OFFICIAL_REMOTE_URL"
+  error "it points to ${BLUE}$REMOTE_URL${RESET} instead"
+  ask_confirmation
+fi
+info "remote for $CURRENT_LOCAL_BRANCH is ${BLUE}$REMOTE"
+
+info "fetching from $REMOTE the PR"
+git remote update "$REMOTE"
+if ! git ls-remote "$REMOTE" | grep pull >/dev/null; then
+  error "remote $REMOTE is not configured to fetch pull requests"
+  error "run: git config remote.$REMOTE.fetch +refs/pull/*/head:refs/remotes/$REMOTE/pr/*"
+  exit 1
+fi
+git fetch "$REMOTE" "refs/pull/$PR/head"
 COMMIT=$(git rev-parse FETCH_HEAD)
-STATUS=$(curl -s "$API/commits/$COMMIT/status" | jq -r '.state')
+info "commit for PR $PR is ${BLUE}$COMMIT"
+
+# Sanity check: merge to a different branch
 
 if [ "$BASE_BRANCH" != "coq:$CURRENT_LOCAL_BRANCH" ]; then
-  echo "Wrong base branch"
-  read -p "Bypass? [y/N] " -n 1 -r
-  echo
-  if [[ ! $REPLY =~ ^[Yy]$ ]]
-  then
-    exit 1
-  fi
+  error "PR requests merge in ${BLUE}$BASE_BRANCH${RESET} but you are merging in ${BLUE}$CURRENT_LOCAL_BRANCH"
+  ask_confirmation
 fi;
 
+# Sanity check: CI failed
+
+STATUS=$(curl -s "$API/commits/$COMMIT/status" | jq -r '.state')
+
 if [ "$STATUS" != "success" ]; then
-  echo "CI status is \"$STATUS\""
-  read -p "Bypass? [y/N] " -n 1 -r
-  echo
-  if [[ ! $REPLY =~ ^[Yy]$ ]]
-  then
-    exit 1
-  fi
+  error "CI unsuccessful on ${BLUE}$(curl -s "$API/commits/$COMMIT/status" |
+    jq -r -c '.statuses|map(select(.state != "success"))|map(.context)')"
+  ask_confirmation
 fi;
 
-git merge -S --no-ff FETCH_HEAD -m "Merge PR #$PR: $(curl -s "$API/pulls/$PR" | jq -r '.title')" -e
+# Sanity check: has labels named "needs:"
+
+NEEDS_LABELS=$(curl -s "$API/pulls/$PR" | jq -rc '.labels | map(select(.name | match("needs:"))) | map(.name)')
+if [ "$NEEDS_LABELS" != "[]" ]; then
+  error "needs:something labels still present: ${BLUE}$NEEDS_LABELS"
+  ask_confirmation
+fi
+
+# Sanity check: has milestone
+
+MILESTONE=$(curl -s "$API/pulls/$PR" | jq -rc '.milestone.title')
+if [ "$MILESTONE" = "null" ]; then
+  error "no milestone set, please set one"
+  ask_confirmation
+fi
+
+# Sanity check: has kind
+
+KIND=$(curl -s "$API/pulls/$PR" | jq -rc '.labels | map(select(.name | match("kind:"))) | map(.name)')
+if [ "$KIND" = "[]" ]; then
+  error "no kind:something label set, please set one"
+  ask_confirmation
+fi
+
+# Sanity check: user.signingkey
+if [ -z "$(git config user.signingkey)" ]; then
+  warning "git config user.signingkey is empty"
+  warning "gpg will guess a key out of your git config user.* data"
+fi
+
+info "merging"
+git merge -v -S --no-ff FETCH_HEAD -m "Merge PR #$PR: $TITLE" -e
 
 # TODO: improve this check
-if ! git diff --quiet "$REMOTE/$CURRENT_LOCAL_BRANCH" -- dev/ci; then
-  echo "******************************************"
-  echo "** WARNING: does this PR have overlays? **"
-  echo "******************************************"
+if ! git diff --quiet "$REMOTE/$CURRENT_LOCAL_BRANCH" -- dev/ci/user-overlays; then
+  warning "this PR may have overlays (sorry the check is not perfect)"
+  warning "if it has overlays please check the following:"
+  warning "- each overlay has a corresponding open PR on the upstream repo"
+  warning "- after merging please notify the upstream they can merge the PR"
 fi