ci: validate for signed MR commits in the CI

- Add a new script to validate for signed commits
- Post a GitLab MR Warning comment listing the unsigned commit details

Signed-off-by: Shubhika Garg <shubhika.garg@openairinterface.org>

ci-scripts/Jenkinsfile-GitLab-Container

@@ -89,6 +89,19 @@ pipeline {
             echo "GitLab Usermail is ${gitCommitAuthorEmailAddr}"
             // GitLab-Jenkins plugin integration is lacking to perform the merge by itself
             // Doing it manually --> it may have merge conflicts
+
+            // Validate MR commits: checks for missing Signed-off-by and merge commits
+            def mrValidationLog = "signedCommit_${env.BUILD_NUMBER}.log"
+            def mrValidationExitCode = sh(
+                script: "bash ./ci-scripts/pre-ci-check.sh -s origin/${env.gitlabSourceBranch} -t origin/${env.gitlabTargetBranch} > ${mrValidationLog} 2>&1",
+                returnStatus: true
+            )
+            def mrValidationMessage = readFile(mrValidationLog).trim()
+            sh "rm -f ${mrValidationLog}"
+            addGitLabMRComment comment: "${mrValidationMessage}"
+            if (mrValidationExitCode >= 2) {
+              error("${mrValidationMessage}")
+            }
             sh "./ci-scripts/doGitLabMerge.sh --src-branch ${env.gitlabSourceBranch} --src-commit ${env.gitlabMergeRequestLastCommit} --target-branch ${env.gitlabTargetBranch} --target-commit ${GIT_COMMIT}"
           } else {
             echo "Git Branch    is ${GIT_BRANCH}"

ci-scripts/pre-ci-check.sh

@@ -0,0 +1,94 @@
+#!/bin/bash
+# SPDX-License-Identifier: LicenseRef-CSSL-1.0
+
+function usage {
+    echo "OAI GitLab MR validation script (Signed-off-by and merge commits)"
+    echo ""
+    echo "Usage:"
+    echo "------"
+    echo "    $0 -s <source-branch> -t <target-branch>"
+    echo ""
+    echo "Options:"
+    echo "--------"
+    echo "    -s"
+    echo "    The source branch of the merge request. Default value is current Git Branch (HEAD)"
+    echo ""
+    echo "    -t"
+    echo "    The target branch of the merge request. Default value is develop"
+    echo ""
+    echo "    -h"
+    echo "    Print this help message."
+    echo ""
+}
+
+# Parse arguments properly
+SOURCE_BRANCH=$(git rev-parse --abbrev-ref HEAD)
+TARGET_BRANCH="origin/develop"
+
+git fetch --quiet
+
+while getopts ":s:t:h" opt; do
+    case "$opt" in
+        s)
+            SOURCE_BRANCH="$OPTARG"
+            ;;
+        t)
+            TARGET_BRANCH="$OPTARG"
+            ;;
+        h)
+            usage
+            exit 0
+            ;;
+        :)
+            echo "Error: Option -$OPTARG requires a value."
+            echo ""
+            usage
+            exit 2
+            ;;
+        \?)
+            echo "Error: Invalid option -$OPTARG"
+            echo ""
+            usage
+            exit 2
+            ;;
+    esac
+done
+
+# ----------------------------
+# Merged commits
+# ----------------------------
+mergeCommits=$(git rev-list --merges --abbrev-commit "$TARGET_BRANCH".."$SOURCE_BRANCH")
+if [[ -n "$mergeCommits" ]]; then
+    message="> ERROR: Following merge commits are found in the source branch history. Please rebase your branch.\n>\n"
+    message+="> $(echo "$mergeCommits" | paste -sd ',' -)\n"
+    echo -e "$message"
+    exit 3
+fi
+
+# ----------------------------
+# Check unsigned commits
+# ----------------------------
+unsignedCommits=$(
+    for c in $(git rev-list "$TARGET_BRANCH".."$SOURCE_BRANCH"); do
+        if ! git log -1 --format=%B "$c" | grep -q "Signed-off-by:"; then
+            git log -1 --format='%h' "$c"
+        fi
+    done | paste -sd ","
+)
+
+# ----------------------------
+# Report unsigned commits
+# ----------------------------
+message=""
+
+if [ -n "$unsignedCommits" ]; then
+    message="> WARNING: The following commit(s) are missing a Signed-off-by:\n>\n> $unsignedCommits\n>\n"
+    message+="> Please use 'git commit -s' to sign your commits.\n>\n"
+    message+="> For detailed instructions, refer to the CONTRIBUTING file at the root of this repository."
+    echo -e "$message"
+    exit 1
+else
+    message="> All commits are signed off using 'git commit -s'."
+    echo -e "$message"
+    exit 0
+fi