ci-automation: Follow-up fix for 2-phase nightly SDK build tags

We push a commit with the nightly SDK tag to the main branch if the
SDK was built from the main branch. Which is what happens when we
build the nightly intermediate SDK. The final nightly SDK is not built
from the main branch, but rather from the nightly intermediate SDK
tag. Both of them point to the exactly same commit, but the difference
is in what `git rev-parse --abbrev-ref HEAD` returns for each of
those. When the main branch is checked out, the command will return
"main". When the nightly intermediate SDK tag is checked out, the
command will return "HEAD". So when nightly final SDK is being built,
the command returns a string different than "main" and thus decides
not to push the commit with the final nightly SDK tag to the main
branch. Rework it to assume that if `git rev-parse HEAD` and `git
rev-parse main` return the same commit hash (and it's the nightly
build and all that) then the commit should be pushed.

ci-automation/ci_automation_common.sh

@@ -23,7 +23,7 @@ function check_version_string() {
 
 function update_and_push_version() {
     local version="$1"
-    local push_to_branch="${2:-false}"
+    local target_branch="${2:-}"
 
     # set up author and email so git does not complain when tagging
     if ! git config --get user.name >/dev/null 2>&1 ; then
@@ -64,9 +64,8 @@ function update_and_push_version() {
 
     git tag -f "${TAG_ARGS[@]}" "${version}"
 
-    if [ "${push_to_branch}" = "true" ]; then
-      local branch="$(git rev-parse --abbrev-ref HEAD)"
-      git push origin "${branch}"
+    if [[ -n "${target_branch}" ]]; then
+      git push origin "HEAD:${target_branch}"
     fi
 
     git push origin "${version}"

ci-automation/packages-tag.sh

@@ -68,11 +68,11 @@ function _packages_tag_impl() {
 
     # Create new tag in scripts repo w/ updated versionfile
     # Also push the changes to the branch ONLY IF we're doing a nightly
-    #   build of the 'main'/'flatcar-MAJOR' branch AND we're definitely ON the respective branch
-    local push_branch="false"
+    #   build of the 'flatcar-MAJOR' branch AND we're definitely ON the respective branch
+    local target_branch=''
     if    [[ "${version}" =~ ^(stable|alpha|beta|lts)-[0-9.]+-nightly-[-0-9]+$ ]] \
        && [[ "$(git rev-parse --abbrev-ref HEAD)" =~ ^flatcar-[0-9]+$ ]] ; then
-        push_branch="true"
+        target_branch="$(git rev-parse --abbrev-ref HEAD)"
         local existing_tag=""
         # Check for the existing tag only when we allow shortcutting
         # the builds. That way we can skip the checks for build
@@ -108,7 +108,7 @@ function _packages_tag_impl() {
       source sdk_lib/sdk_container_common.sh
       create_versionfile "$sdk_version" "$version"
     )
-    update_and_push_version "${version}" "${push_branch}"
+    update_and_push_version "${version}" "${target_branch}"
     apply_local_patches
 }
 # --

ci-automation/sdk_bootstrap.sh

@@ -78,10 +78,10 @@ function _sdk_bootstrap_impl() {
     # Also push the changes to the branch ONLY IF we're doing a nightly
     #   build of the 'main' branch AND we're definitely ON the main branch.
     #   This includes intermediate SDKs when doing 2-phase nightly builds.
-    local push_branch="false"
+    local target_branch=''
     if   [[ "${version}" =~ ^main-[0-9.]+-nightly-[-0-9]+(-INTERMEDIATE)?$ ]] \
-       && [ "$(git rev-parse --abbrev-ref HEAD)" = "main"  ] ; then
-        push_branch="true"
+       && [ "$(git rev-parse HEAD)" = "$(git rev-parse main)"  ] ; then
+        target_branch='main'
         local existing_tag=""
         # Check for the existing tag only when we allow shortcutting
         # the builds. That way we can skip the checks for build
@@ -132,7 +132,7 @@ function _sdk_bootstrap_impl() {
       source sdk_lib/sdk_container_common.sh
       create_versionfile "${vernum}"
     )
-    update_and_push_version "${version}" "${push_branch}"
+    update_and_push_version "${version}" "${target_branch}"
     apply_local_patches
 
     ./bootstrap_sdk_container -x ./ci-cleanup.sh "${seed_version}" "${vernum}"