github-merge-pr: introduce new script to merge pr on github

Introduce a new script github-merge-pr.sh to facilitate merging pr from
github by flagging them as actually merged.

Assuming you are in the github repo.

Usage: github-merge-pr.sh <PR-ID> [rebase-branch] [dry-run]

PR-ID is PR #ID
rebase-branch is master to be rebased on (master,openwrt2..03...)
dry-run doesn't execute anything and is used to check what command will
be executed

Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>

diff --git a/github-merge-pr.sh b/github-merge-pr.sh
new file mode 100755 (executable)
index 0000000..12e7466
--- /dev/null
+++ b/github-merge-pr.sh
@@ -0,0 +1,144 @@
+#!/bin/bash
+
+# Github repository, just the name/repo part, no .git suffix, no base url!
+REPO="openwrt/openwrt"
+
+# Your repository token, generate this token at your profile page:
+# - Navigate to https://github.com/settings/tokens
+# - Click on "Generate new token"
+# - Enter a description, e.g. "pr.sh" and pick the "repo" scope
+# - Hit "Generate token"
+#TOKEN="d41d8cd98f00b204e9800998ecf8427e"
+
+PRID="$1"
+BRANCH="${2:-master}"
+DRY_RUN="$3"
+GIT=git
+
+if ! command -v jq &> /dev/null; then
+       echo "jq could not be found! This script require jq!"
+       exit 1
+fi
+
+if [ -z "$PRID" -o -n "${PRID//[0-9]*/}" ]; then
+       echo "Usage: $0 <PR-ID> [rebase-branch] [dry-run]" >&2
+       exit 1
+fi
+
+if [ -n "$DRY_RUN" ]; then
+       GIT="echo git"
+fi
+
+if [ -z "$(git branch --list "$BRANCH")" ]; then
+       echo "Given rebase branch '$BRANCH' does not exist!" >&2
+       exit 2
+fi
+
+if ! PR_INFO="$(curl -f -s "https://api.github.com/repos/$REPO/pulls/$PRID")"; then
+       echo "Failed fetch PR #$PRID info" >&2
+       exit 3
+fi
+
+if [ "$(echo "$PR_INFO" | jq -r ".maintainer_can_modify")" == "false" ]; then
+       echo "PR #$PRID can't be force pushed by maintainers. Can't merge this PR!" >&2
+       echo 4
+fi
+
+if [ "$(echo "$PR_INFO" | jq -r ".mergeable")" == "false" ]; then
+       echo "PR #$PRID is not mergeable for Github.com. Check the PR!" >&2
+       echo 5
+fi
+
+echo "Pulling current $BRANCH from origin"
+$GIT checkout $BRANCH
+$GIT fetch origin
+
+if ! $GIT rebase origin/$BRANCH; then
+       echo "Failed to rebase $BRANCH with origin/$BRANCH" >&2
+       echo 7
+fi
+
+PR_USER="$(echo "$PR_INFO" | jq -r ".head.user.login")"
+PR_BRANCH="$(echo "$PR_INFO" | jq -r ".head.ref")"
+PR_REPO="$(echo "$PR_INFO" | jq -r ".head.repo.html_url")"
+
+if ! $GIT remote get-url $PR_USER &> /dev/null || [ -n "$DRY_RUN" ]; then
+       echo "Adding $PR_USER with repo $PR_REPO to remote"
+       $GIT remote add  $PR_USER $PR_REPO
+fi
+
+echo "Fetching remote $PR_USER"
+$GIT fetch $PR_USER
+
+echo "Creating branch $PR_BRANCH"
+if ! $GIT checkout -b $PR_BRANCH $PR_USER/$PR_BRANCH; then
+       echo "Failed to checkout new branch $PR_BRANCH from $PR_USER/$PR_BRANCH" >&2
+       echo 8
+fi
+
+echo "Rebasing $PR_BRANCH on top of $BRANCH"
+if ! $GIT rebase origin/$BRANCH; then
+       echo "Failed to rebase $PR_BRANCH with origin/$BRANCH" >&2
+       echo 9
+fi
+
+echo "Force pushing $PR_BRANCH to $PR_USER"
+if ! $GIT push $PR_USER HEAD --force; then
+       echo "Failed to force push HEAD to $PR_USER" >&2
+       echo 10
+fi
+
+echo "Returning to $BRANCH"
+$GIT checkout $BRANCH
+
+echo "Actually merging the PR #$PRID from branch $PR_USER/$PR_BRANCH"
+if ! $GIT merge --ff-only $PR_USER/$PR_BRANCH; then
+       echo "Failed to merge $PR_USER/$PR_BRANCH on $BRANCH" >&2
+       echo 11
+fi
+
+echo "Pushing to openwrt git server"
+if ! $GIT push; then
+       echo "Failed to push to $BRANCH but left branch as is." >&2
+       echo 12
+fi
+
+echo "Deleting branch $PR_BRANCH"
+$GIT branch -D $PR_BRANCH
+
+# Default close comment
+COMMENT="Thanks! Rebased on top of $BRANCH and merged!"
+
+if [ -n "$TOKEN" ] && [ -z "$DRY_RUN" ]; then
+       echo ""
+       echo "Enter a comment and hit <enter> to close the PR at Github automatically now."
+       echo "Hit <ctrl>-<c> to exit."
+       echo ""
+       echo "If you do not provide a comment, the default will be: "
+       echo "[$COMMENT]"
+
+       echo -n "Comment > "
+       read usercomment
+
+       echo "Sending message to PR..."
+
+       comment="${usercomment:-$COMMENT}"
+       comment="${comment//\\/\\\\}"
+       comment="${comment//\"/\\\"}"
+       comment="$(printf '{"body":"%s"}' "$comment")"
+
+       if ! curl -s -o /dev/null -w "%{http_code} %{url_effective}\\n" --user "$TOKEN:x-oauth-basic" --request POST --data "$comment" "https://api.github.com/repos/$REPO/issues/$PRID/comments" || \
+          ! curl -s -o /dev/null -w "%{http_code} %{url_effective}\\n" --user "$TOKEN:x-oauth-basic" --request PATCH --data '{"state":"closed"}' "https://api.github.com/repos/$REPO/pulls/$PRID"
+       then
+               echo ""                                                     >&2
+               echo "Something failed while sending comment to the PR via ">&2
+               echo "the Github API, please review the state manually at " >&2
+               echo "https://github.com/$REPO/pull/$PRID"                  >&2
+               exit 6
+       fi
+fi
+
+echo ""
+echo "The PR has been merged!"
+
+exit 0