Mercurial Repositories > eric / file diff

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/eric7/Plugins/CheckerPlugins/CodeStyleChecker/Miscellaneous/DefaultMatchCaseVisitor.py	Thu Feb 27 14:42:39 2025 +0100
@@ -0,0 +1,121 @@
+# -*- coding: utf-8 -*-
+
+# Copyright (c) 2025 Detlev Offenbach <detlev@die-offenbachs.de>
+#
+
+"""
+Module implementing a node visitor to check default match cases.
+"""
+
+import ast
+
+
+class DefaultMatchCaseVisitor(ast.NodeVisitor):
+    """
+    Class implementing a node visitor to check default match cases.
+
+    Note: This class is modeled after flake8-spm v0.0.1.
+    """
+
+    def __init__(self):
+        """
+        Constructor
+        """
+        super().__init__()
+
+        self.violations = []
+
+    def visit_Match(self, node):
+        """
+        Public method to handle Match nodes.
+
+        @param node reference to the node to be processed
+        @type ast.Match
+        """
+        for badNode, issueCode in self.__badNodes(node):
+            self.violations.append((badNode, issueCode))
+
+        self.generic_visit(node)
+
+    def __badNodes(self, node):
+        """
+        Private method to yield bad match nodes.
+
+        @param node reference to the node to be processed
+        @type ast.Match
+        @yield tuple containing a reference to bad match case node and the corresponding
+            issue code
+        @ytype tyuple of (ast.AST, str)
+        """
+        for case in node.cases:
+            if self.__emptyMatchDefault(case):
+                if self.__lastStatementDoesNotRaise(case):
+                    yield self.__findBadNode(case), "M-901"
+                elif self.__returnPrecedesExceptionRaising(case):
+                    yield self.__findBadNode(case), "M-902"
+
+    def __emptyMatchDefault(self, case):
+        """
+        Private method to check for an empty default match case.
+
+        @param case reference to the node to be processed
+        @type ast.match_case
+        @return flag indicating an empty default match case
+        @rtype bool
+        """
+        pattern = case.pattern
+        return isinstance(pattern, ast.MatchAs) and (
+            pattern.pattern is None
+            or (
+                isinstance(pattern.pattern, ast.MatchAs)
+                and pattern.pattern.pattern is None
+            )
+        )
+
+    def __lastStatementDoesNotRaise(self, case):
+        """
+        Private method to check that the last case statement does not raise an
+        exception.
+
+        @param case reference to the node to be processed
+        @type ast.match_case
+        @return flag indicating that the last case statement does not raise an
+            exception
+        @rtype bool
+        """
+        return not isinstance(case.body[-1], ast.Raise)
+
+    def __returnPrecedesExceptionRaising(self, case):
+        """
+        Private method to check that no return precedes an exception raising.
+
+        @param case reference to the node to be processed
+        @type ast.match_case
+        @return flag indicating that a return precedes an exception raising
+        @rtype bool
+        """
+        returnIndex = -1
+        raiseIndex = -1
+        for index, body in enumerate(case.body):
+            if isinstance(body, ast.Return):
+                returnIndex = index
+            elif isinstance(body, ast.Raise):
+                raiseIndex = index
+        return returnIndex >= 0 and returnIndex < raiseIndex
+
+    def __findBadNode(self, case) -> ast.AST:
+        """
+        Private method returning a reference to the bad node of a case node.
+
+        @param case reference to the node to be processed
+        @type ast.match_case
+        @return reference to the bad node
+        @rtype ast.AST
+        """
+        for body in case.body:
+            # Handle special case when return precedes exception raising.
+            # In this case the bad node is that with the return statement.
+            if isinstance(body, ast.Return):
+                return body
+
+        return case.body[-1]