[used-before-assignment] Fix FP under finally block

Closes #9451

Author: jacobtylerwalls

doc/whatsnew/fragments/9451.false_positive

@@ -0,0 +1,4 @@
+Fix false positive for ``used-before-assignment`` in a ``finally`` block
+when assignments took place in both the ``try`` block and each exception handler.
+
+Closes #9451

pylint/checkers/variables.py

@@ -667,7 +667,7 @@ def get_next_to_consume(self, node: nodes.Name) -> list[nodes.NodeNG] | None:
         if found_nodes:
             uncertain_nodes = (
                 self._uncertain_nodes_in_try_blocks_when_evaluating_finally_blocks(
-                    found_nodes, node_statement
+                    found_nodes, node_statement, name
                 )
             )
             self.consumed_uncertain[node.name] += uncertain_nodes
@@ -1140,7 +1140,9 @@ def _uncertain_nodes_in_try_blocks_when_evaluating_except_blocks(
 
     @staticmethod
     def _uncertain_nodes_in_try_blocks_when_evaluating_finally_blocks(
-        found_nodes: list[nodes.NodeNG], node_statement: _base_nodes.Statement
+        found_nodes: list[nodes.NodeNG],
+        node_statement: _base_nodes.Statement,
+        name: str,
     ) -> list[nodes.NodeNG]:
         uncertain_nodes: list[nodes.NodeNG] = []
         (
@@ -1187,6 +1189,12 @@ def _uncertain_nodes_in_try_blocks_when_evaluating_finally_blocks(
                 )
             ):
                 continue
+            # Is the name defined in all exception clauses?
+            if other_node_try_finally_ancestor.handlers and all(
+                NamesConsumer._defines_name_raises_or_returns_recursive(name, handler)
+                for handler in other_node_try_finally_ancestor.handlers
+            ):
+                continue
             # Passed all tests for uncertain execution
             uncertain_nodes.append(other_node)
         return uncertain_nodes

tests/functional/u/used/used_before_assignment_issue85.py

@@ -34,6 +34,16 @@ def try_except_finally_assignment_in_final_block():
     print(res)
 
 
+def try_except_finally_assignment_in_both_try_and_except():
+    """Assignment of the name in both try and except blocks is fine."""
+    try:
+        res = 1 / 0
+    except ZeroDivisionError:
+        res = 0
+    finally:
+        print(res)
+
+
 def try_except_finally_nested_try_finally_in_try():
     """Don't confuse assignments in different finally statements where
     one is nested inside a try.

tests/functional/u/used/used_before_assignment_issue85.txt

@@ -1,10 +1,10 @@
 used-before-assignment:8:14:8:17:main:Using variable 'res' before assignment:CONTROL_FLOW
 used-before-assignment:20:14:20:17:try_except_finally:Using variable 'res' before assignment:CONTROL_FLOW
-used-before-assignment:45:18:45:21:try_except_finally_nested_try_finally_in_try:Using variable 'res' before assignment:HIGH
-used-before-assignment:70:18:70:29:try_except_finally_nested_in_finally:Using variable 'outer_times' before assignment:CONTROL_FLOW
-used-before-assignment:84:18:84:29:try_except_finally_nested_in_finally_2:Using variable 'inner_times' before assignment:CONTROL_FLOW
-used-before-assignment:85:14:85:25:try_except_finally_nested_in_finally_2:Using variable 'outer_times' before assignment:CONTROL_FLOW
-used-before-assignment:100:18:100:29:try_except_finally_nested_in_finally_3:Using variable 'inner_times' before assignment:CONTROL_FLOW
-used-before-assignment:101:18:101:29:try_except_finally_nested_in_finally_3:Using variable 'outer_times' before assignment:CONTROL_FLOW
-used-before-assignment:122:22:122:33:try_except_finally_nested_in_finally_4:Using variable 'inner_times' before assignment:CONTROL_FLOW
-used-before-assignment:123:22:123:33:try_except_finally_nested_in_finally_4:Using variable 'outer_times' before assignment:CONTROL_FLOW
+used-before-assignment:55:18:55:21:try_except_finally_nested_try_finally_in_try:Using variable 'res' before assignment:HIGH
+used-before-assignment:80:18:80:29:try_except_finally_nested_in_finally:Using variable 'outer_times' before assignment:CONTROL_FLOW
+used-before-assignment:94:18:94:29:try_except_finally_nested_in_finally_2:Using variable 'inner_times' before assignment:CONTROL_FLOW
+used-before-assignment:95:14:95:25:try_except_finally_nested_in_finally_2:Using variable 'outer_times' before assignment:CONTROL_FLOW
+used-before-assignment:110:18:110:29:try_except_finally_nested_in_finally_3:Using variable 'inner_times' before assignment:CONTROL_FLOW
+used-before-assignment:111:18:111:29:try_except_finally_nested_in_finally_3:Using variable 'outer_times' before assignment:CONTROL_FLOW
+used-before-assignment:132:22:132:33:try_except_finally_nested_in_finally_4:Using variable 'inner_times' before assignment:CONTROL_FLOW
+used-before-assignment:133:22:133:33:try_except_finally_nested_in_finally_4:Using variable 'outer_times' before assignment:CONTROL_FLOW