fix: set newline='' on TextIOWrapper in stdio_server to prevent Windows CRLF corruption#2574
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EvanYao826 wants to merge 3 commits into
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fix: set newline='' on TextIOWrapper in stdio_server to prevent Windows CRLF corruption#2574EvanYao826 wants to merge 3 commits into
EvanYao826 wants to merge 3 commits into
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…ws CRLF corruption On Windows, TextIOWrapper defaults to platform-native line endings (\r\n), which corrupts newline-delimited JSON-RPC messages over stdio. Add newline='' to both the stdin and stdout TextIOWrapper constructors in stdio_server(), matching the pattern from PR modelcontextprotocol#2302. Fixes modelcontextprotocol#2433
When a Windows MCP server emits CRLF (\r\n) line endings, the client's
stdout_reader splits on \n alone, leaving a trailing \r on each line.
This causes JSON parsing to fail since "{...}\r" is not valid JSON.
Fix by stripping trailing \r from each line before JSON parsing in the
client's stdio_reader. Also adds a test that verifies CRLF-terminated
messages from a server are correctly parsed.
Fixes modelcontextprotocol#2433
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Fixes #2433
Summary
On Windows,
TextIOWrapperdefaults to platform-native line endings (stdio_server()wrapssys.stdoutin aTextIOWrapperwithout specifyingnewline=, so anyFix
Add
newline=to theTextIOWrapperconstructor instdio_server(), matching the pattern already used in the server-side fix from PR #2302.Test
Added a test verifying that the TextIOWrapper used in stdio_server has
newline=set, preventing CRLF conversion.