[Fix rails#55379] Default branch in github ci templates

Author: endenis

railties/lib/rails/generators/app_base.rb

@@ -529,8 +529,13 @@ def using_bun?
         using_js_runtime? && %w[bun].include?(options[:javascript])
       end
 
-      def capture_command(command, pattern)
-        `#{command}`[pattern]
+      def capture_command(command, pattern = nil)
+        output = `#{command}`
+        if pattern
+          output[pattern]
+        else
+          output
+        end
       rescue SystemCallError
         nil
       end
@@ -760,11 +765,13 @@ def keep_file(destination)
       end
 
       def user_default_branch
-        @user_default_branch ||= `git config init.defaultbranch`
+        @user_default_branch ||= capture_command("git config init.defaultbranch").strip.presence || "main"
       end
 
       def git_init_command
-        return "git init" if user_default_branch.strip.present?
+        if capture_command("git config init.defaultbranch").present?
+          return "git init"
+        end
 
         git_version = `git --version`[/\d+\.\d+\.\d+/]
 

railties/lib/rails/generators/rails/app/templates/github/ci.yml.tt

@@ -3,7 +3,7 @@ name: CI
 on:
   pull_request:
   push:
-    branches: [ main ]
+    branches: [ <%= user_default_branch %> ]
 
 jobs:
 <%- unless skip_brakeman? -%>

railties/lib/rails/generators/rails/plugin/templates/github/ci.yml.tt

@@ -3,7 +3,7 @@ name: CI
 on:
   pull_request:
   push:
-    branches: [ main ]
+    branches: [ <%= user_default_branch %> ]
 
 jobs:
 <%- unless skip_rubocop? -%>

railties/test/generators/app_generator_test.rb

@@ -1150,6 +1150,7 @@ def test_default_branch_main_without_user_default
 
     run_generator [destination_root]
     assert_file ".git/HEAD", /main/
+    assert_file ".github/workflows/ci.yml", /branches: \[ main \]/
   ensure
     if !current_default_branch.strip.empty?
       `git config --global init.defaultBranch #{current_default_branch}`
@@ -1165,6 +1166,7 @@ def test_version_control_initializes_git_repo_with_user_default_branch
 
     run_generator [destination_root]
     assert_file ".git/HEAD", /master/
+    assert_file ".github/workflows/ci.yml", /branches: \[ master \]/
   ensure
     if current_default_branch && current_default_branch.strip.empty?
       `git config --global --unset init.defaultBranch`

railties/test/generators/plugin_generator_test.rb

@@ -145,6 +145,7 @@ def test_initializes_git_repo_with_main_branch_without_user_default
 
     run_generator
     assert_file ".git/HEAD", /main/
+    assert_file ".github/workflows/ci.yml", /branches: \[ main \]/
   ensure
     if !current_default_branch.strip.empty?
       `git config --global init.defaultBranch #{current_default_branch}`
@@ -160,6 +161,7 @@ def test_version_control_initializes_git_repo_with_user_default_branch
 
     run_generator
     assert_file ".git/HEAD", /master/
+    assert_file ".github/workflows/ci.yml", /branches: \[ master \]/
   ensure
     if current_default_branch && current_default_branch.strip.empty?
       `git config --global --unset init.defaultBranch`