mv sigint handling to __main__

This code is only relevant to the CLI, having it in __main__ directly
simplifies to control flow around setting the sigint handler.

Author: amorison

stagpy/__init__.py

@@ -9,44 +9,7 @@
 to issue warnings normally and raise StagpyError.
 """
 
-from __future__ import annotations
-
-import os
-import signal
-import sys
-import typing
-
-if typing.TYPE_CHECKING:
-    from typing import Any, NoReturn
-
-
-DEBUG = os.getenv("STAGPY_DEBUG") is not None
-
-
-def sigint_handler(*_: Any) -> NoReturn:
-    """Handler of SIGINT signal.
-
-    It is set when you use StagPy as a command line tool to handle gracefully
-    keyboard interruption.
-    """
-    print("\nSo long, and thanks for all the fish.")
-    sys.exit()
-
-
-if DEBUG:
-    print(
-        "StagPy runs in DEBUG mode because the environment variable",
-        'STAGPY_DEBUG is set to "True"',
-        sep="\n",
-        end="\n\n",
-    )
-else:
-    _PREV_INT = signal.signal(signal.SIGINT, sigint_handler)
-
 try:
     from ._version import version as __version__
 except ImportError:
     __version__ = "unknown"
-
-if not DEBUG:
-    signal.signal(signal.SIGINT, _PREV_INT)

stagpy/__main__.py

@@ -1,17 +1,36 @@
 """The stagpy module is callable."""
 
+from __future__ import annotations
+
+import os
 import signal
 import sys
 import warnings
+from typing import Any, NoReturn
+
+
+def sigint_handler(*_: Any) -> NoReturn:
+    """Handler of SIGINT signal.
 
-from . import DEBUG, sigint_handler
+    It is set when you use StagPy as a command line tool to handle gracefully
+    keyboard interruption.
+    """
+    print("\nSo long, and thanks for all the fish.")
+    sys.exit()
 
 
 def main() -> None:
     """Implement StagPy entry point."""
-    if not DEBUG:
+    debug = os.getenv("STAGPY_DEBUG") is not None
+    if debug:
+        print(
+            "env variable 'STAGPY_DEBUG' is set: StagPy runs in DEBUG mode",
+            end="\n\n",
+        )
+    else:
         signal.signal(signal.SIGINT, sigint_handler)
         warnings.simplefilter("ignore")
+
     from . import args, config, error
 
     conf = config.Config.default_()
@@ -21,7 +40,7 @@ def main() -> None:
     try:
         args.parse_args(conf)(conf)
     except error.StagpyError as err:
-        if DEBUG:
+        if debug:
             raise
         errtype = type(err).__name__
         print(