Added clear_resolver method to OmegaConf

CONTRIBUTING.md

@@ -18,8 +18,8 @@ pre-commit will verify your code lints cleanly when you commit. You can use `git
 OmegaConf is compatible with Python 3.6.4 and newer. Unfortunately Mac comes with older versions.
 
 One way to install multiple Python versions on Mac to to use pyenv.
-The instructions [here](https://github.com/GoogleCloudPlatform/python-docs-samples/blob/master/MAC_SETUP.md) 
-will provide full details. It shows how to use pyenv on mac to install multiple versions of Python and have 
+The instructions [here](https://github.com/GoogleCloudPlatform/python-docs-samples/blob/master/MAC_SETUP.md)
+will provide full details. It shows how to use pyenv on mac to install multiple versions of Python and have
 pyenv make specific versions available in specific directories automatically.
 This plays well with Conda, which supports a single Python version. Pyenv will provide the versions not installed by Conda (which are used when running nox).
 
@@ -49,23 +49,24 @@ Sessions defined in /home/omry/dev/omegaconf/noxfile.py:
 * test_jupyter_notebook-3.8
 * test_jupyter_notebook-3.9
 ```
+
 To run a specific session use `-s`, for example `nox -s lint` will run linting
 
 
 OmegaConf is formatted with black, to format your code automatically use `black .`
 
-Imports are sorted using isort, use `isort .` to sort all imports prior to pushing.  
+Imports are sorted using isort, use `isort .` to sort all imports prior to pushing.
 
 To build the docs execute `nox -s docs` or `make`(inside docs folder). Make gives you different options, for example, you can build the docs as html files with `make html`. Once the docs are built you can open `index.html` in the build directory to view the generated docs with your browser.
 
 ### Modifying Jupyter notebook
 
 In order to change the Jupyter notebook you first need to open it with `jupyter notebook`.
-Change the cell you want and then, execute it so the expected output is shown. 
-Note that the output after you execute the cell is saved as expected ouput for further 
+Change the cell you want and then, execute it so the expected output is shown.
+Note that the output after you execute the cell is saved as expected ouput for further
 testing.
 
-In case that the in[number] of cells aren't in order you should go to the 
+In case that the in[number] of cells aren't in order you should go to the
 kernel in the toolbar and restart it.
 
 

omegaconf/omegaconf.py

@@ -467,6 +467,21 @@ def clear_resolvers() -> None:
         BaseContainer._resolvers = {}
         register_default_resolvers()
 
+    @classmethod
+    def clear_resolver(cls, name: str) -> bool:
+        """Clear(remove) any resolver only if it exists. Returns a bool: True if resolver is removed and False if not removed.
+
+        .. warning:
+            This method can remove deafult resolvers as well.
+
+        :param name: Name of the resolver.
+        :return: A bool (``True`` if resolver is removed, ``False`` if not removed).
+        """
+        if cls.has_resolver(name):  # pragma: nocover
+            _ = BaseContainer._resolvers.pop(name)
+
+        return not cls.has_resolver(name)
+
     @staticmethod
     def get_cache(conf: BaseContainer) -> Dict[str, Any]:
         return conf._metadata.resolver_cache

tests/test_omegaconf.py

@@ -518,3 +518,93 @@ def test_resolve(cfg: Any, expected: Any) -> None:
 def test_resolve_invalid_input() -> None:
     with raises(ValueError):
         OmegaConf.resolve("aaa")  # type: ignore
+
+
+@mark.parametrize(
+    ("cfg_params,clear_resolver_params,expected"),
+    [
+        # tuple
+        (
+            # cfg_params
+            dict(
+                name="TR1",
+                resolver=lambda x: str(x).lower(),
+                use_cache=False,
+                replace=True,
+            ),
+            # clear_resolver_params
+            dict(name="TR1"),
+            # expected
+            dict(pre_addition=False, post_addition=True, post_removal=False),
+        ),
+        # tuple
+        (
+            # cfg_params
+            dict(
+                name="TR2",
+                resolver=lambda x: str(x).upper(),
+                use_cache=False,
+                replace=True,
+            ),
+            # clear_resolver_params
+            dict(name="TR2"),
+            # expected
+            dict(pre_addition=False, post_addition=True, post_removal=False),
+        ),
+        # tuple
+        (
+            # cfg_params
+            dict(
+                name="TR3",
+                resolver=lambda x: str(x).upper(),
+                use_cache=False,
+                replace=False,
+            ),
+            # clear_resolver_params
+            dict(name="TR3"),
+            # expected
+            dict(pre_addition=False, post_addition=True, post_removal=False),
+        ),
+        # tuple
+        (
+            # cfg_params: Check with a default resolver
+            dict(),
+            # clear_resolver_params
+            dict(name="oc.env"),
+            # expected
+            dict(pre_addition=True, post_addition=True, post_removal=False),
+        ),
+        # tuple
+        (
+            # cfg_params: Check with a default resolver
+            dict(),
+            # clear_resolver_params
+            dict(name="oc.create"),
+            # expected
+            dict(pre_addition=True, post_addition=True, post_removal=False),
+        ),
+        # tuple
+        (
+            # cfg_params: Check with a nonexisting resolver
+            dict(),
+            # clear_resolver_params
+            dict(name="abcdef"),
+            # expected
+            dict(pre_addition=False, post_addition=False, post_removal=False),
+        ),
+    ],
+)
+def test_clear_resolver(
+    cfg_params: Any, clear_resolver_params: Any, expected: Any
+) -> None:
+
+    OmegaConf.clear_resolvers()
+    name = clear_resolver_params.get("name")
+    assert expected["pre_addition"] == OmegaConf.has_resolver(name)
+    if cfg_params:
+        OmegaConf.register_new_resolver(**cfg_params)
+        assert expected["post_addition"] == OmegaConf.has_resolver(name)
+
+    assert OmegaConf.clear_resolver(**clear_resolver_params)
+
+    assert expected["post_removal"] == OmegaConf.has_resolver(name)