Fix AttributeError when accessing Response.text with Payload body

CHANGES/2928.bugfix.rst

@@ -0,0 +1 @@
+Changed ``AttributeError`` to ``TypeError`` when accessing ``Response.text`` after setting ``body`` to a value that becomes a ``Payload`` without a ``decode`` method.

aiohttp/web_response.py

@@ -636,10 +636,13 @@ def body(self, body: Any) -> None:
     def text(self) -> str | None:
         if self._body is None:
             return None
-        # Note: When _body is a Payload (e.g. FilePayload), this may do blocking I/O
-        # This is generally safe as most common payloads (BytesPayload, StringPayload)
-        # don't do blocking I/O, but be careful with file-based payloads
-        return self._body.decode(self.charset or "utf-8")
+        try:
+            return self._body.decode(self.charset or "utf-8")
+        except AttributeError:
+            raise TypeError(
+                f"Unable to get text from body type {type(self._body).__name__}. "
+                f"Use the text setter or pass text= to Response() for string content."
+            )
 
     @text.setter
     def text(self, text: str) -> None: