checkout to default branch instead of master

tests/rules/test_git_branch_delete_checked_out.py

@@ -1,4 +1,7 @@
+from mock import patch
+
 import pytest
+
 from thefuck.rules.git_branch_delete_checked_out import match, get_new_command
 from thefuck.types import Command
 
@@ -25,5 +28,18 @@ def test_not_match(script):
         ("git branch -D foo", "git checkout master && git branch -D foo"),
     ],
 )
-def test_get_new_command(script, new_command, output):
-    assert get_new_command(Command(script, output)) == new_command
+def test_get_new_command_deletion_flag(script, new_command, output):
+    with patch('thefuck.rules.git_branch_delete_checked_out.get_sp_stdout', return_value='master'):
+        assert get_new_command(Command(script, output)) == new_command
+
+
+@pytest.mark.parametrize(
+    "script, default_branch",
+    [
+        ("git branch -d foo", "main"),
+        ("git branch -d foo", "bar"),
+    ],
+)
+def test_get_new_command_default_branch(script, default_branch, output):
+    with patch('thefuck.rules.git_branch_delete_checked_out.get_sp_stdout', return_value=default_branch):
+        assert get_new_command(Command(script, output)) == "git checkout {default_branch} && git branch -D foo".format(default_branch=default_branch)

thefuck/rules/git_branch_delete_checked_out.py

@@ -1,8 +1,13 @@
+import subprocess as sp
+
 from thefuck.shells import shell
 from thefuck.specific.git import git_support
 from thefuck.utils import replace_argument
 
 
+STDOUT_INDEX = 0
+
+
 @git_support
 def match(command):
     return (
@@ -12,8 +17,14 @@ def match(command):
     )
 
 
+def get_sp_stdout(command):
+    return sp.Popen(command, stdout=sp.PIPE, shell=True).communicate()[STDOUT_INDEX].strip().decode("utf-8")
+
+
 @git_support
 def get_new_command(command):
-    return shell.and_("git checkout master", "{}").format(
+    remote_name = get_sp_stdout("git remote")
+    default_branch_name = get_sp_stdout("git remote show {remote} | sed -n '/HEAD branch/s/.*: //p'".format(remote=remote_name))
+    return shell.and_("git checkout {default_branch}".format(default_branch=default_branch_name), "{}").format(
         replace_argument(command.script, "-d", "-D")
     )