Replace git flow with regular git commands in the release script V2

The script was relying on the external git-flow tool and on a local
`git config gitflow.*` initialisation, which made its behaviour depend on
the machine setup and hid what was actually done to the branches.

The release branch is now created with `git checkout -b`, and the release
is finished with explicit merge, tag, back-merge and branch deletion
commands. The merge and tag messages are provided explicitly so that the
generated history stays identical to the previous releases. Each step now
aborts the script with a clear message when it fails, instead of letting
the script continue.

Note that tools/release/release.sh (V1) still uses git flow.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

tools/release/releaseV2.sh

@@ -5,7 +5,7 @@
 # SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
 # Please see LICENSE files in the repository root for full details.
 
-# do not exit when any command fails (issue with git flow)
+# do not exit when any command fails, failures are handled explicitly by the script
 set +e
 
 printf "\n================================================================================\n"
@@ -63,6 +63,12 @@ if [ ${envError} == 1 ]; then
   exit 1
 fi
 
+# Abort the script with an error message.
+fail() {
+  printf "\nFatal: %s\n" "$1"
+  exit 1
+}
+
 # Handle the result of a version check. ${checkError} must be set to 1 when a check has failed.
 checkVersionResult() {
   if [[ ${checkError} -ne 0 ]]; then
@@ -97,16 +103,6 @@ if [[ ${unmergedPrs} != "" ]]; then
 fi
 
 
-# Check if git flow is enabled
-gitFlowDevelop=$(git config gitflow.branch.develop)
-if [[ ${gitFlowDevelop} != "" ]]
-then
-    printf "Git flow is initialized\n"
-else
-    printf "Git flow is not initialized. Initializing...\n"
-    ./tools/gitflow/gitflow-init.sh
-fi
-
 printf "OK\n"
 
 printf "\n================================================================================\n"
@@ -149,7 +145,7 @@ versionReleaseNumber=$(echo "${version}" | cut  -d "." -f3)
 
 printf "\n================================================================================\n"
 printf "Starting the release %s\n" "${version}"
-git flow release start "${version}"
+git checkout -b "release/${version}" develop
 
 # Note: in case the release is already started and the script is started again, checkout the release branch again.
 ret=$?
@@ -160,7 +156,7 @@ if [[ $ret -ne 0 ]]; then
   read -r -p "Continue (yes/no) default to yes? " doContinue
   doContinue=${doContinue:-yes}
   if [ "${doContinue}" == "no" ]; then
-    printf "OK, exiting, you can start the release again with the command 'git flow release start %s'\n" "${version}"
+    printf "OK, exiting, you can start the release again with the command 'git checkout -b release/%s develop'\n" "${version}"
     exit 1
   fi
   git checkout "release/${version}"
@@ -197,10 +193,17 @@ git commit -a -m "Adding fastlane file for version ${version}"
 
 printf "\n================================================================================\n"
 printf "OK, finishing the release...\n"
-# GIT_MERGE_AUTOEDIT avoids opening the editor for the 2 merge commits, whose default message is
-# always used, and -m provides the message of the annotated tag. git flow appends the tag name to
-# it, so the tag message ends up being "Release v${version}".
-GIT_MERGE_AUTOEDIT=no git flow release finish -m "Release" "${version}"
+# Merge the release branch into main, tag it, then merge the tag back into develop and delete the
+# release branch. The merge messages are provided explicitly to keep the history consistent with
+# the previous releases.
+git checkout main || fail "unable to checkout main."
+git merge --no-ff --no-edit -m "Merge branch 'release/${version}'" "release/${version}" \
+  || fail "unable to merge the branch release/${version} into main. Please fix the conflicts and finish the release manually."
+git tag -a "v${version}" -m "Release v${version}" || fail "unable to create the tag v${version}."
+git checkout develop || fail "unable to checkout develop."
+git merge --no-ff --no-edit -m "Merge tag 'v${version}' into develop" "v${version}" \
+  || fail "unable to merge the tag v${version} into develop. Please fix the conflicts and finish the release manually."
+git branch -d "release/${version}" || fail "unable to delete the branch release/${version}."
 
 printf "\n================================================================================\n"
 read -r -p "Done, push the branch 'main' and the new tag (yes/no) default to yes? " doPush