Fix a regression in 0.26.0 that caused kitty to no longer set the LANG environment variable on macOS

Happened because reading the locale uses cocoa APIs and they are not fork
safe, so it was moved to after prewarm forking, but at that point the
default child env had already been set.

Fixes #5439

docs/changelog.rst

@@ -40,6 +40,8 @@ Detailed list of changes
 
 - ssh kitten: Fix executable permission missing from kitty bootstrap script (:iss:`5438`)
 
+- Fix a regression in 0.26.0 that caused kitty to no longer set the ``LANG`` environment variable on macOS (:iss:`5439`)
+
 0.26.0 [2022-08-29]
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 

kitty/child.py

@@ -168,6 +168,10 @@ def set_default_env(val: Optional[Dict[str, str]] = None) -> None:
     setattr(default_env, 'lc_ctype_set_by_user', has_lctype)
 
 
+def set_LANG_in_default_env(val: str) -> None:
+    default_env()['LANG'] = val
+
+
 def openpty() -> Tuple[int, int]:
     master, slave = os.openpty()  # Note that master and slave are in blocking mode
     os.set_inheritable(slave, True)

kitty/main.py

@@ -10,7 +10,7 @@ from typing import Dict, Generator, List, Optional, Sequence, Tuple
 
 from .borders import load_borders_program
 from .boss import Boss
-from .child import set_default_env
+from .child import set_default_env, set_LANG_in_default_env
 from .cli import create_opts, parse_args
 from .cli_stub import CLIOptions
 from .conf.utils import BadLine
@@ -229,6 +229,7 @@ def ensure_macos_locale() -> None:
                 else:
                     log_error(f'Could not set LANG Cocoa returns language as: {lang}')
             os.environ['LANG'] = f'{lang}.UTF-8'
+            set_LANG_in_default_env(os.environ['LANG'])
 
 
 @contextmanager
@@ -368,6 +369,7 @@ def set_locale() -> None:
             except Exception:
                 log_error('Failed to set locale with no LANG')
             os.environ['LANG'] = old_lang
+            set_LANG_in_default_env(old_lang)
 
 
 def _main() -> None: