Improve hotfix lane to work when there's no release tag

Author: iangmaia

fastlane/Fastfile

@@ -82,9 +82,18 @@ platform :android do
     previous_version = VERSION_FORMATTER.release_version(
       VERSION_CALCULATOR.previous_patch_version(version: VERSION_FORMATTER.parse(new_version))
     )
+    previous_release_branch = release_branch_name(release_version: previous_version)
 
     UI.user_error!("The version `#{new_version}` tag already exists!") if git_tag_exists(tag: new_version)
-    UI.user_error!("Version #{previous_version} is not tagged! A hotfix branch cannot be created.") unless git_tag_exists(tag: previous_version)
+
+    # Determine the base for the hotfix branch: either a tag or a release branch
+    base_ref_for_hotfix = if git_tag_exists(tag: previous_version)
+                            previous_version
+                          elsif Fastlane::Helper::GitHelper.branch_exists_on_remote?(branch_name: previous_release_branch)
+                            previous_release_branch
+                          else
+                            UI.user_error!("Neither tag #{previous_version} nor branch #{previous_release_branch} exists! A hotfix branch cannot be created.")
+                          end
 
     message = <<~MESSAGE
       Hotfix release:
@@ -94,14 +103,14 @@ platform :android do
       - Current build code: #{build_code_current}
       - New build code: #{version_code_new}
 
-      Branching from tag: #{previous_version}
+      Branching from #{base_ref_for_hotfix}
     MESSAGE
     UI.important(message)
 
     UI.user_error!("Terminating as requested. Don't forget to run the remainder of this automation manually.") unless skip_confirm || UI.confirm('Do you want to continue?')
 
-    UI.message('Creating hotfix branch...')
-    Fastlane::Helper::GitHelper.create_branch(release_branch_name(release_version: new_version), from: previous_version)
+    UI.message("Creating hotfix branch from #{base_ref_for_hotfix}...")
+    Fastlane::Helper::GitHelper.create_branch(release_branch_name(release_version: new_version), from: base_ref_for_hotfix)
     UI.success("Done! New hotfix branch is: #{git_branch}")
 
     UI.message('Bumping hotfix version and build code...')