feat(TMP-1717): Add PR validation check (#4013)

* added check-pr-branch to circleci yaml

* added check-pr-branch.sh

* fixed executor to node

* updated logic of CircleCI PR branch check

* removed 20-30s unnecessary checkout

* replaced job with inline command run

* changed order of check PR

* removed unintended newline on cci yaml file

.circleci/check-pr-branch.sh

@@ -0,0 +1,30 @@
+#!/bin/bash
+
+if [[ "$CIRCLE_BRANCH" == "master" ]];
+then
+  echo "Skipping PR branch check for master branch"
+  exit 0
+fi
+
+echo "Checking PR branch is up to date with master branch"
+
+current_branch=$(git branch --show-current)
+merge_base=$(git merge-base $current_branch master)
+recommend_rebase="rebase your branch on the master branch."
+
+# checking if PR branch is up to date
+if ! git diff -s --exit-code $current_branch...master ; then
+  echo "Branch ${current_branch} is not up-to-date with master. Please, ${recommend_rebase}"
+  exit 1
+fi
+
+# checking if there is no new merge commit
+current_commit=$(git show-ref --heads -s $current_branch)
+for commit in $(git log $current_commit...$merge_base --format="%h"); do
+  parent_count=$(git cat-file -p $commit | grep parent | wc -l)
+  if [ "${parent_count}" != 1 ]; then
+    commit_msg=$(git log $commit -1 --format="%s")
+    echo "Merge commits like ${commit} (${commit_msg}) are not allowed. Please ${recommend_rebase}"
+    exit 1
+  fi
+done

.circleci/config.yml

@@ -48,6 +48,9 @@ jobs:
     executor: node
     steps:
       - checkout
+      - run:
+          name: "Check if PR is up-to-date and there are no merge commits"
+          command: ./.circleci/check-pr-branch.sh
       - restore-yarn
       - install-dependencies
       - save-yarn
@@ -305,7 +308,6 @@ workflows:
       - run_cypress_tests:
           requires:
             - setup
-
       - verdaccio-test-approval:
           <<: *only_on_master_branch
           type: approval