Managing thirdparty package: defer.

thirdparty/defer/sugar/_parse.py

@@ -0,0 +1,67 @@
+import sys
+from ast import (
+    AsyncFunctionDef,
+    FunctionDef,
+)
+from collections import deque
+from types import FrameType
+from typing import Any, Callable, Optional, cast
+
+from executing.executing import Executing, Source
+
+from defer.errors import FreeVarsError
+from defer.sugar.transformer import RewriteDefer
+
+
+class _ParseDefer:
+    IDENTITY = lambda *_: None  # noqa: E731
+
+    def __init__(self, tracefn: Optional[Callable]) -> None:
+        self.tracefn = tracefn or self.IDENTITY
+        self.pending: deque[Executing] = deque()
+
+    def __call__(self, frame: FrameType, event: str, arg: Any):
+        self.tracefn(frame, event, arg)
+
+        if any(
+            frame.f_code.co_filename.startswith(path)
+            for path in {
+                sys.base_exec_prefix,
+                sys.base_prefix,
+                sys.exec_prefix,
+                sys.prefix,
+                "<frozen ",
+                "<string>",
+                "<pytest ",
+            }
+        ):
+            return self
+
+        if event != "line":
+            return self
+
+        if not (stmt := next(iter(exc.statements), None)):
+            return self
+        if isinstance(stmt, (AsyncFunctionDef, FunctionDef)):
+            if stmt.name.startswith("__") and stmt.name.endswith("__"):
+                return self
+            self.pending.append(exc)
+            return self
+            return self
+
+        stmts = self.pending.pop().statements
+        node = cast(FunctionDef | AsyncFunctionDef, next(iter(stmts)))
+        fn = frame.f_locals[node.name]
+
+        if fn.__module__ in sys.stdlib_module_names:
+            return self
+        if fn.__code__.co_freevars:
+            raise FreeVarsError(fn)
+        if not (ast := RewriteDefer.transform(node)):
+            return self
+
+        locals = frame.f_locals.copy()
+        del locals[node.name]
+        exec(compile(ast, frame.f_code.co_filename, "exec"), frame.f_globals, locals)
+        frame.f_locals[node.name].__code__ = locals[node.name].__code__
+        return self