Fix remote branch deletion without local tracking refs

CHANGELOG.md

@@ -14,7 +14,7 @@ _None_
 
 ### Bug Fixes
 
-_None_
+- `GitHelper.delete_remote_branch_if_exists!` now detects branches directly on the remote instead of requiring a local remote-tracking ref. [#769]
 
 ### Internal Changes
 

lib/fastlane/plugin/wpmreleasetoolkit/helper/git_helper.rb

@@ -267,13 +267,13 @@ def self.delete_local_branch_if_exists!(branch_name)
       #
       # @param [String] branch_name The name of the remote branch to delete.
       # @param [String] remote_name The name of the remote to delete the branch from. Defaults to 'origin'
-      # @return [Boolean] true if the branch was deleted, false if not (e.g. no such local branch existed in the first place)
+      # @return [Boolean] true if the branch was deleted, false if it did not exist on the remote
       #
       def self.delete_remote_branch_if_exists!(branch_name, remote_name: 'origin')
-        git_repo = Git.open(Dir.pwd)
-        return false unless git_repo.branches.any? { |b| b.remote&.name == remote_name && b.name == branch_name }
+        return false unless branch_exists_on_remote?(branch_name: branch_name, remote_name: remote_name)
 
-        git_repo.push(remote_name, branch_name, delete: true)
+        Git.open(Dir.pwd).push(remote_name, branch_name, delete: true)
+        true
       end
 
       # Checks whether a given path is ignored by Git, relying on Git's `check-ignore` under the hood.

spec/git_helper_spec.rb

@@ -186,6 +186,33 @@
     end
   end
 
+  describe 'delete_remote_branch_if_exists!' do
+    let(:branch_name) { 'automation/update' }
+    let(:remote_name) { 'upstream' }
+
+    before do
+      init_git_repo
+      add_file_and_commit(file: 'file.txt', message: 'Initial commit')
+
+      remote_path = File.join(@path, 'remote.git')
+      `git init --bare --initial-branch main #{remote_path}`
+      `git remote add #{remote_name} #{remote_path}`
+    end
+
+    it 'deletes a branch that exists on the remote without requiring a local tracking ref' do
+      `git push #{remote_name} HEAD:refs/heads/#{branch_name}`
+      `git update-ref -d refs/remotes/#{remote_name}/#{branch_name}`
+
+      expect(`git branch --remotes --list #{remote_name}/#{branch_name}`).to be_empty
+      expect(described_class.delete_remote_branch_if_exists!(branch_name, remote_name: remote_name)).to be true
+      expect(described_class.branch_exists_on_remote?(branch_name: branch_name, remote_name: remote_name)).to be false
+    end
+
+    it 'does nothing when the branch does not exist on the remote' do
+      expect(described_class.delete_remote_branch_if_exists!(branch_name, remote_name: remote_name)).to be false
+    end
+  end
+
   describe '#is_ignored?' do
     let(:path) { 'dummy.txt' }