bundle.sh: allow a PR # to be specified

Allow pull requests (and merge requests) to be specified by using a
branch name like "pr/111" or "mr/222". This allows CI to use this
script as well, instead of multiple variations of the same thing.

Additonally allow the destination directory to be overridden with the
DESTDIR environment variable.

scripts/bundle.sh

@@ -4,10 +4,63 @@
 #
 # To use, run from the top Suricata source directory:
 #
-#    ./scripts/bundle.sh
+#    ./scripts/bundle.sh [suricata-update|libhtp]
+#
+# If no arguments are provided, both suricata-update and libhtp will
+# be bundled.
+#
+# Environment variables:
+#
+#   SU_REPO:   Overrides the Suricata-Update git repo
+#   SU_BRANCH: Override the Suricata-Update branch to a branch, tag or
+#              {pull,merge}-request.
+#
+#   LIBHTP_REPO:   Overrides the libhtp git repo
+#   LIBHTP_BRANCH: Override the libhtp branch to a branch, tag or
+#                  {pull,merge}-request.
+#
+#   DESTDIR: Checkout to another directory instead of the current
+#            directory.
+#
+# To specify a pull or merge request in a branch name in the format of
+# pr/NNN or mr/NNN.
+
+set -e
+
+DESTDIR=${DESTDIR:-.}
 
 what="$1"
 
+# Transforms a branch name in the form of "pr/<NUMBER>" or
+# "mr/<NUMBER>" into a proper ref for GitHub or Gitlab.
+transform_branch() {
+    pr=$(echo "${1}" | sed -n 's/^pr\/\([[:digit:]]\+\)$/\1/p')
+    if [ "${pr}" ]; then
+        echo "refs/pull/${pr}/head"
+        return
+    fi
+
+    mr=$(echo "${1}" | sed -n 's/^mr\/\([[:digit:]]\+\)$/\1/p')
+    if [ "${mr}" ]; then
+        echo "refs/merge-requests/${mr}/head"
+        return
+    fi
+
+    echo "${1}"
+}
+
+fetch() {
+    repo="$1"
+    dest="$2"
+    branch="$3"
+
+    git clone --depth 1 "${repo}" "${dest}"
+    pushd "${dest}"
+    git fetch origin "${branch}"
+    git -c advice.detachedHead=false checkout FETCH_HEAD
+    popd
+}
+
 while IFS= read -r requirement; do
     set -- $requirement
 
@@ -20,20 +73,22 @@ while IFS= read -r requirement; do
     fi
     case "$1" in
         suricata-update)
-            repo=${SU_REPO:-$2}
-            branch=${SU_BRANCH:-$3}
-            echo "===> Bundling ${repo} -b ${branch}"
-            rm -rf suricata-update.tmp
-            git clone "${repo}" -b "${branch}" suricata-update.tmp
-            cp -a suricata-update.tmp/* suricata-update/
-            rm -rf suricata-update.tmp
+            SU_REPO=${SU_REPO:-$2}
+            SU_BRANCH=$(transform_branch ${SU_BRANCH:-$3})
+            echo "===> Bundling ${SU_REPO} (${SU_BRANCH})"
+            rm -rf ${DESTDIR}/suricata-update.tmp
+            fetch "${SU_REPO}" "${DESTDIR}/suricata-update.tmp" "${SU_BRANCH}"
+            rm -rf ${DESTDIR}/suricata-update.tmp/.git
+            cp -a ${DESTDIR}/suricata-update.tmp/. ${DESTDIR}/suricata-update
+            rm -rf ${DESTDIR}/suricata-update.tmp
             ;;
         libhtp)
-            repo=${LIBHTP_REPO:-$2}
-            branch=${LIBHTP_BRANCH:-$3}
-            echo "===> Bundling ${repo} -b ${branch}"
-            rm -rf libhtp
-            git clone "${repo}" -b "${branch}" libhtp
+            LIBHTP_REPO=${LIBHTP_REPO:-$2}
+            LIBHTP_BRANCH=$(transform_branch ${LIBHTP_BRANCH:-$3})
+            echo "===> Bundling ${LIBHTP_REPO} (${LIBHTP_BRANCH})"
+            rm -rf ${DESTDIR}/libhtp
+            fetch "${LIBHTP_REPO}" "${DESTDIR}/libhtp" "${LIBHTP_BRANCH}"
+            rm -rf libhtp/.git
             ;;
         \#*)
             # Ignore comment.