Fix python#13881: Add plugin to disallow bytearray as filename in compile()

Author: vidhyavijayan3

mypy.ini

@@ -0,0 +1,2 @@
+[mypy]
+plugins = compile_filename.plugin

plugins/__init__.py

@@ -0,0 +1,33 @@
+from typing import Optional
+from mypy.plugin import Plugin, FunctionContext
+from mypy.types import Type, Instance
+from mypy.nodes import ARG_POS
+
+class CompileFilenamePlugin(Plugin):
+    def get_function_hook(self, fullname: str):
+        # Hook only the built-in compile function
+        if fullname == "builtins.compile":
+            return compile_hook
+        return None
+
+def compile_hook(ctx: FunctionContext) -> Type:
+    # Arguments to compile: source, filename, mode, ...
+    # filename is arg index 1 (zero-based)
+    if len(ctx.arg_types) > 1 and ctx.arg_types[1]:
+        filename_type = ctx.arg_types[1][0]  # first argument passed for filename param
+        if is_bytearray_type(filename_type):
+            ctx.api.fail(
+                "Passing 'bytearray' as filename to 'compile()' is not allowed",
+                ctx.args[1][0]
+            )
+    return ctx.default_return_type
+
+def is_bytearray_type(typ: Type) -> bool:
+    # Check if the type is exactly bytearray
+    if isinstance(typ, Instance):
+        # The full name for builtins.bytearray is 'builtins.bytearray'
+        return typ.type.fullname == "builtins.bytearray"
+    return False
+
+def plugin(version: str):
+    return CompileFilenamePlugin