Wrap logger manipulation around a lock

Just doing it as the standard library does, even if I do not have the proof it is the right thing to do

Author: kdeldycke

click_extra/logging.py

@@ -146,37 +146,39 @@ def extra_basic_config(
         Add more parameters for even greater configurability of the logger, by
         re-implementing those supported by ``logging.basicConfig``.
     """
-    # Fetch the logger or create a new one.
-    logger = logging.getLogger(logger_name)
-
-    # Remove and close any existing handlers. Copy of:
-    # https://github.com/python/cpython/blob/2b5dbd1/Lib/logging/__init__.py#L2028-L2031
-    if force:
-        for h in logger.handlers[:]:
-            logger.removeHandler(h)
-            h.close()
-
-    # If no handlers provided, create a new one with the default handler class.
-    if not handlers:
-        handlers = (handler_class(),)
-
-    # Set up the formatter with a default message format.
-    formatter = formatter_class(
-        fmt=format,
-        datefmt=datefmt,
-        style=style,
-    )
+    with logging._lock:
+        # Fetch the logger or create a new one.
+        logger = logging.getLogger(logger_name)
+
+        # Remove and close any existing handlers. Copy of:
+        # https://github.com/python/cpython/blob/2b5dbd1/Lib/logging/__init__.py#L2028-L2031
+        # https://loguru.readthedocs.io/en/stable/resources/recipes.html#avoiding-logs-to-be-printed-twice-on-the-terminal
+        if force:
+            for h in logger.handlers[:]:
+                logger.removeHandler(h)
+                h.close()
+
+        # If no handlers provided, create a new one with the default handler class.
+        if not handlers:
+            handlers = (handler_class(),)
+
+        # Set up the formatter with a default message format.
+        formatter = formatter_class(
+            fmt=format,
+            datefmt=datefmt,
+            style=style,
+        )
 
-    # Attach handlers to the loggers.
-    for h in handlers:
-        if h.formatter is None:
-            h.setFormatter(formatter)
-        logger.addHandler(h)
+        # Attach handlers to the loggers.
+        for h in handlers:
+            if h.formatter is None:
+                h.setFormatter(formatter)
+            logger.addHandler(h)
 
-    if level is not None:
-        logger.setLevel(level)
+        if level is not None:
+            logger.setLevel(level)
 
-    return logger
+        return logger
 
 
 class VerbosityOption(ExtraOption):
@@ -273,15 +275,16 @@ def __init__(
         if not param_decls:
             param_decls = ("--verbosity", "-v")
 
-        # Use the provided logger instance as-is.
-        if isinstance(default_logger, Logger):
-            logger = default_logger
-        # If a string is provided, use it as the logger name.
-        elif isinstance(default_logger, str):
-            logger = logging.getLogger(default_logger)
-        # ``None`` will produce a default root logger.
-        else:
-            logger = extra_basic_config(default_logger)
+        with logging._lock:
+            # A logger object has been provided, use it as-is.
+            if isinstance(default_logger, Logger):
+                logger = default_logger
+            # Retrieves the logger object as it is from the registry, if it exists.
+            elif default_logger in logging.Logger.manager.loggerDict:
+                logger = logging.getLogger(default_logger)
+            # Create a new logger with Click Extra's default configuration.
+            else:
+                logger = extra_basic_config(default_logger)
 
         # Store the logger name for later use.
         self.logger_name = logger.name