From 2c0d1870f0c8e73440d85c06735a24947803dec7 Mon Sep 17 00:00:00 2001
From: Tony Meyer <tony.meyer@canonical.com>
Date: Wed, 18 Dec 2024 13:12:55 +1300
Subject: [PATCH] Remove the ops.main.main deprecation warning, as per
 Charm-Tech discussion.

---
 ops/main.py                  | 60 ++----------------------------------
 test/test_main_invocation.py | 12 --------
 2 files changed, 2 insertions(+), 70 deletions(-)

diff --git a/ops/main.py b/ops/main.py
index 24978e19c..728d8e88d 100644
--- a/ops/main.py
+++ b/ops/main.py
@@ -14,10 +14,7 @@
 
 """Support legacy ops.main.main() import."""
 
-import inspect
-import os
-import warnings
-from typing import Any, Optional, Type, Union
+from typing import Optional, Type
 
 import ops.charm
 
@@ -32,14 +29,6 @@
 )
 
 
-def _top_frame():
-    frame = inspect.currentframe()
-    while frame:
-        if frame.f_back is None:
-            return frame
-        frame = frame.f_back
-
-
 def main(charm_class: Type[ops.charm.CharmBase], use_juju_for_storage: Optional[bool] = None):
     """Legacy entrypoint to set up the charm and dispatch the observed event.
 
@@ -48,49 +37,4 @@ def main(charm_class: Type[ops.charm.CharmBase], use_juju_for_storage: Optional[
 
     See `ops.main() <#ops-main-entry-point>`_ for details.
     """
-    # Normally, we would do warnings.warn() with a DeprecationWarning, but at
-    # this point in the charm execution, the framework has not been set up, so
-    # we haven't had a chance to direct warnings where we want them to go. That
-    # means that they'll end up going to stderr, and with actions that means
-    # they'll end up being displayed to the user.
-    # This means that we need to delay emitting the warning until the framework
-    # has been set up, so we wrap the charm and do it on instantiation. However,
-    # this means that a regular warning call won't provide the correct filename
-    # and line number.
-    # Note also that this will be logged with every event. Our assumption is
-    # that this will be noticeable enough during integration testing that it
-    # will get fixed before going into production.
-    frame = _top_frame()
-    assert frame is not None
-
-    class DeprecatedMainCharmBase(charm_class):
-        def __init__(self, *args: Any, **kwargs: Any):
-            super().__init__(*args, **kwargs)
-
-            _original_format = warnings.formatwarning
-
-            def custom_warning_formatter(
-                message: Union[str, Warning],
-                category: Type[Warning],
-                *args: Any,
-                **kwargs: Any,
-            ) -> str:
-                """Like the default formatter, but patch in the filename and line number."""
-                return (
-                    f'{frame.f_code.co_filename}:{frame.f_lineno}: '
-                    f'{category.__name__}: {message}'
-                )
-
-            try:
-                warnings.formatwarning = custom_warning_formatter
-                warnings.warn(
-                    'Calling `ops.main()` is deprecated, call `ops.main()` instead',
-                    DeprecationWarning,
-                    stacklevel=2,
-                )
-            finally:
-                warnings.formatwarning = _original_format
-
-    return _main.main(
-        charm_class=DeprecatedMainCharmBase, use_juju_for_storage=use_juju_for_storage
-    )
+    return _main.main(charm_class=charm_class, use_juju_for_storage=use_juju_for_storage)
diff --git a/test/test_main_invocation.py b/test/test_main_invocation.py
index 4105b3c17..3796d99a2 100644
--- a/test/test_main_invocation.py
+++ b/test/test_main_invocation.py
@@ -52,9 +52,6 @@ def test_top_level_import(charm_env: None):
 def test_top_level_import_legacy_call(charm_env: None):
     import ops
 
-    with pytest.deprecated_call():
-        ops.main.main(ops.CharmBase)
-
     with pytest.raises(TypeError):
         ops.main.main()  # type: ignore
 
@@ -71,9 +68,6 @@ def test_submodule_import(charm_env: None):
 def test_submodule_import_legacy_call(charm_env: None):
     import ops.main
 
-    with pytest.deprecated_call():
-        ops.main.main(ops.CharmBase)
-
     with pytest.raises(TypeError):
         ops.main.main()  # type: ignore
 
@@ -90,9 +84,6 @@ def test_import_from_top_level_module(charm_env: None):
 def test_import_from_top_level_module_legacy_call(charm_env: None):
     from ops import main
 
-    with pytest.deprecated_call():
-        main.main(ops.CharmBase)
-
     with pytest.raises(TypeError):
         main.main()  # type: ignore
 
@@ -100,8 +91,5 @@ def test_import_from_top_level_module_legacy_call(charm_env: None):
 def test_legacy_import_from_submodule(charm_env: None):
     from ops.main import main
 
-    with pytest.deprecated_call():
-        main(ops.CharmBase)
-
     with pytest.raises(TypeError):
         main()  # type: ignore