Environment variable to disable plugins (#8767)

Co-authored-by: pantero <pantero@panteros-MacBook-Pro.local>
Co-authored-by: Marcelo Trylesinski <marcelotryle@gmail.com>

docs/concepts/plugins.md

@@ -116,3 +116,12 @@ class Foo(BaseModel, plugin_settings={'observer': 'all'}):
 ```
 
 On each validation call, the `plugin_settings` will be passed to a callable registered for the events.
+
+## Disabling Plugins
+
+You can use environment variable `PYDANTIC_DISABLE_PLUGINS` to disable all or specific plugin(s).
+
+| Environment Variable          | Allowed Values                                        | Description                   |
+|-------------------------------|-------------------------------------------------------|-------------------------------|
+| `PYDANTIC_DISABLE_PLUGINS`    | `__all__`, `1`, `true`                                | Disables all plugins          |
+|                               | Comma-separated string (e.g. `my-plugin-1,my-plugin2`)| Disables specified plugin(s)  |

pydantic/plugin/_loader.py

@@ -1,6 +1,7 @@
 from __future__ import annotations
 
 import importlib.metadata as importlib_metadata
+import os
 import warnings
 from typing import TYPE_CHECKING, Final, Iterable
 
@@ -22,10 +23,13 @@ def get_plugins() -> Iterable[PydanticPluginProtocol]:
 
     Inspired by: https://github.com/pytest-dev/pluggy/blob/1.3.0/src/pluggy/_manager.py#L376-L402
     """
+    disabled_plugins = os.getenv('PYDANTIC_DISABLE_PLUGINS')
     global _plugins, _loading_plugins
     if _loading_plugins:
         # this happens when plugins themselves use pydantic, we return no plugins
         return ()
+    elif disabled_plugins in ('__all__', '1', 'true'):
+        return ()
     elif _plugins is None:
         _plugins = {}
         # set _loading_plugins so any plugins that use pydantic don't themselves use plugins
@@ -37,6 +41,8 @@ def get_plugins() -> Iterable[PydanticPluginProtocol]:
                         continue
                     if entry_point.value in _plugins:
                         continue
+                    if disabled_plugins is not None and entry_point.name in disabled_plugins.split(','):
+                        continue
                     try:
                         _plugins[entry_point.value] = entry_point.load()
                     except (ImportError, AttributeError) as e:

tests/test_plugin_loader.py

@@ -0,0 +1,83 @@
+import importlib.metadata as importlib_metadata
+import os
+from unittest.mock import patch
+
+import pytest
+
+import pydantic.plugin._loader as loader
+
+
+class EntryPoint:
+    def __init__(self, name, value, group):
+        self.name = name
+        self.value = value
+        self.group = group
+
+    def load(self):
+        return self.value
+
+
+class Dist:
+    entry_points = []
+
+    def __init__(self, entry_points):
+        self.entry_points = entry_points
+
+
+@pytest.fixture
+def reset_plugins():
+    global loader
+    initial_plugins = loader._plugins
+    loader._plugins = None
+    yield
+    # teardown
+    loader._plugins = initial_plugins
+
+
+@pytest.fixture(autouse=True)
+def mock():
+    mock_entry_1 = EntryPoint(name='test_plugin1', value='test_plugin:plugin1', group='pydantic')
+    mock_entry_2 = EntryPoint(name='test_plugin2', value='test_plugin:plugin2', group='pydantic')
+    mock_entry_3 = EntryPoint(name='test_plugin3', value='test_plugin:plugin3', group='pydantic')
+    mock_dist = Dist([mock_entry_1, mock_entry_2, mock_entry_3])
+
+    with patch.object(importlib_metadata, 'distributions', return_value=[mock_dist]):
+        yield
+
+
+def test_loader(reset_plugins):
+    res = loader.get_plugins()
+    assert list(res) == ['test_plugin:plugin1', 'test_plugin:plugin2', 'test_plugin:plugin3']
+
+
+def test_disable_all(reset_plugins):
+    os.environ['PYDANTIC_DISABLE_PLUGINS'] = '__all__'
+    res = loader.get_plugins()
+    assert res == ()
+
+
+def test_disable_all_1(reset_plugins):
+    os.environ['PYDANTIC_DISABLE_PLUGINS'] = '1'
+    res = loader.get_plugins()
+    assert res == ()
+
+
+def test_disable_true(reset_plugins):
+    os.environ['PYDANTIC_DISABLE_PLUGINS'] = 'true'
+    res = loader.get_plugins()
+    assert res == ()
+
+
+def test_disable_one(reset_plugins):
+    os.environ['PYDANTIC_DISABLE_PLUGINS'] = 'test_plugin1'
+    res = loader.get_plugins()
+    assert len(list(res)) == 2
+    assert 'test_plugin:plugin1' not in list(res)
+
+
+def test_disable_multiple(reset_plugins):
+    os.environ['PYDANTIC_DISABLE_PLUGINS'] = 'test_plugin1,test_plugin2'
+    res = loader.get_plugins()
+    assert len(list(res)) == 1
+    assert 'test_plugin:plugin1' not in list(res)
+    assert 'test_plugin:plugin2' not in list(res)