Fix FTPDownloadHandler not closing connection after download

download_request() created an FTPClient but never called client.quit()
to close the control connection. On the CommandFailed path, protocol.close()
was also missing, which could leave an open file handle for local-filename
downloads.

Refactored to try/except/else/finally so protocol.close() is called in both
success and CommandFailed paths, and client.quit() is always awaited in the
finally block, with its own exception suppressed to avoid masking the original
error.

Fixes #7602

Co-authored-by: Claude

scrapy/core/downloader/handlers/ftp.py

@@ -113,15 +113,22 @@ class FTPDownloadHandler(BaseDownloadHandler):
         try:
             await maybe_deferred_to_future(client.retrieveFile(filepath, protocol))
         except CommandFailed as e:
+            protocol.close()
             message = str(e)
             if m := _CODE_RE.search(message):
                 ftpcode = m.group()
                 httpcode = self.CODE_MAPPING.get(ftpcode, self.CODE_MAPPING["default"])
                 return Response(url=request.url, status=httpcode, body=message.encode())
             raise
-        protocol.close()
-        headers = {"local filename": protocol.filename or b"", "size": protocol.size}
-        body = protocol.filename or protocol.body.read()
-        respcls = responsetypes.from_args(url=request.url, body=body)
-        # hints for Headers-related types may need to be fixed to not use AnyStr
-        return respcls(url=request.url, status=200, body=body, headers=headers)  # type: ignore[arg-type]
+        else:
+            protocol.close()
+            headers = {"local filename": protocol.filename or b"", "size": protocol.size}
+            body = protocol.filename or protocol.body.read()
+            respcls = responsetypes.from_args(url=request.url, body=body)
+            # hints for Headers-related types may need to be fixed to not use AnyStr
+            return respcls(url=request.url, status=200, body=body, headers=headers)  # type: ignore[arg-type]
+        finally:
+            try:
+                await maybe_deferred_to_future(client.quit())
+            except Exception:
+                pass