Join server threads before closing IO pipes in stdio client tests#280
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koic merged 1 commit intomodelcontextprotocol:mainfrom Mar 31, 2026
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Background threads simulating server responses could race with the `ensure` block that closes IO pipes, intermittently producing this warning depending on thread scheduling: ```console #<Thread:0x00007fb69290cbd0 test/mcp/client/stdio_test.rb:28 run> terminated with exception (report_on_exception is true): test/mcp/client/stdio_test.rb:55:in `write': stream closed in another thread (IOError) ``` Store each background thread in a `server_thread` variable and call `server_thread&.join(1)` at the top of each `ensure` block to wait for the thread to finish before closing pipes.
atesgoral
approved these changes
Mar 31, 2026
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Motivation and Context
Background threads simulating server responses could race with the
ensureblock that closes IO pipes, intermittently producing this warning depending on thread scheduling:Store each background thread in a
server_threadvariable and callserver_thread&.join(1)at the top of eachensureblock to wait for the thread to finish before closing pipes.How Has This Been Tested?
This verifies that no race condition occurs.
Breaking Changes
None. This change updates only the test code.
Types of changes
Checklist