Check availability of the source branch on remote too.

And fetch and checkout it when available.

Author: godunko

.gitlab-ci.yml

@@ -6,7 +6,7 @@ stages:
   - build_and_test
 
 .detect-branches:
-  #  Version 1.
+  #  Version 2.
   #  Detects source and target branches. Checkout necessary branch for
   #  repository when run downstream pipeline is detected.
   #    ACI_SOURCE_BRANCH is set to source branch (merge request, pull)
@@ -47,10 +47,18 @@ stages:
 
   #  On downstream pipeline checkout the necessary branch
   - if [[ "$CI_PIPELINE_SOURCE" == 'pipeline' ]]; then
-       if `git -C $CI_PROJECT_DIR show-ref $ACI_SOURCE_BRANCH > /dev/null`; then
+      if `git -C $CI_PROJECT_DIR show-ref $ACI_SOURCE_BRANCH > /dev/null`; then
+        git -C $CI_PROJECT_DIR checkout $ACI_SOURCE_BRANCH;
+      elif `git -C $CI_PROJECT_DIR ls-remote --exit-code --heads origin $ACI_SOURCE_BRANCH > /dev/null`; then
+        git -C $CI_PROJECT_DIR config remote.origin.fetch "+refs/heads/*:refs/remotes/origin/*"
+        git -C $CI_PROJECT_DIR remote update
         git -C $CI_PROJECT_DIR checkout $ACI_SOURCE_BRANCH;
       elif `git -C $CI_PROJECT_DIR show-ref $ACI_TARGET_BRANCH > /dev/null`; then
         git -C $CI_PROJECT_DIR checkout $ACI_TARGET_BRANCH;
+      elif `git -C $CI_PROJECT_DIR ls-remote --exit-code --heads origin $ACI_TARGET_BRANCH > /dev/null`; then
+        git -C $CI_PROJECT_DIR config remote.origin.fetch "+refs/heads/*:refs/remotes/origin/*"
+        git -C $CI_PROJECT_DIR remote update
+        git -C $CI_PROJECT_DIR checkout $ACI_TARGET_BRANCH;
       fi
     fi