Change clear_cache method to work with table_tree (#213)

* Change clear_cache method to work with table_tree

The table_tree cannot be removed as an attribute as it is a property.
Setting the _table_tree value to its default of None will force, any call to table_tree to recompute the table_tree cache

* Update pre-commit and move flake8 repo to github

* Set Table Cached properties as a list and test that all belong are cached properties

* Add deleter to table tree property to make it work with delattr

* Add docstring to test

* Treat table tree as a non cache property (because it is not)

* Empty-Commit

* Ignore typing errors on Python 3.10

On Python 3.10 the logger has defined the extra as optional.

* Set assertions to validate values is not None

src/widgetastic/log.py

@@ -43,6 +43,7 @@ class PrependParentsAdapter(logging.LoggerAdapter):
     def process(
         self, msg: str, kwargs: MutableMapping[str, Any]
     ) -> Tuple[str, MutableMapping[str, Any]]:
+        assert self.extra is not None  # python 3.10+ type check
         widget_path = cast(str, self.extra["widget_path"])
         # Sanitizing %->%% for formatter working properly
         return (
@@ -51,6 +52,7 @@ def process(
         )
 
     def __repr__(self) -> str:
+        assert self.extra is not None  # python 3.10+ type check
         return "{}({!r}, {!r})".format(type(self).__name__, self.logger, self.extra["widget_path"])
 
 

src/widgetastic/widget/table.py

@@ -408,6 +408,14 @@ class MyCustomTable(Table):
 
     Row = TableRow
 
+    _CACHED_PROPERTIES = [
+        "headers",
+        "attributized_headers",
+        "header_index_mapping",
+        "index_header_mapping",
+        "assoc_column_position",
+    ]
+
     def __init__(
         self,
         parent,
@@ -445,6 +453,10 @@ def table_tree(self):
         if self.has_rowcolspan:
             return self._get_table_tree()
 
+    @table_tree.deleter
+    def table_tree(self):
+        self._table_tree = None
+
     @cached_property
     def resolver(self):
         return TableResolver()
@@ -485,18 +497,12 @@ def _process_negative_index(self, nindex):
 
     def clear_cache(self):
         """Clear all cached properties."""
-        for item in [
-            "headers",
-            "attributized_headers",
-            "header_index_mapping",
-            "index_header_mapping",
-            "assoc_column_position",
-            "table_tree",
-        ]:
+        for item in self._CACHED_PROPERTIES:
             try:
                 delattr(self, item)
             except AttributeError:
                 pass
+        del self.table_tree
 
     @cached_property
     def headers(self):

testing/test_table.py

@@ -0,0 +1,31 @@
+from cached_property import cached_property
+
+from widgetastic.widget import Table
+from widgetastic.widget import View
+
+
+def test_table_cached_properties():
+    """Cached properties are defined as such"""
+    for item in Table._CACHED_PROPERTIES:
+        attribute = getattr(Table, item)
+        assert isinstance(attribute, cached_property)
+
+
+def test_table_clear_cache(browser):
+    class TestForm(View):
+        table = Table("#rowcolspan_table")
+
+    view = TestForm(browser)
+    table = view.table
+
+    # invoke properties
+    for item in Table._CACHED_PROPERTIES:
+        getattr(table, item)
+    tree = table.table_tree
+    assert tree is not None, "If the table has not row or col span it won't have a tree"
+
+    table.clear_cache()
+
+    for item in Table._CACHED_PROPERTIES:
+        assert item not in table.__dict__
+    assert table._table_tree is None