REPL unusable within VSCode's integrated terminal

[headquarter8302]

What version of Bun is running?

1.3.4+5eb2145b3

What platform is your computer?

Microsoft Windows NT 10.0.26200.0 x64

What steps can reproduce the bug?

1. Open Visual Studio Code
2. Open its integrated terminal
3. Run bun repl
4. Wait for the REPL to load
5. Garbled output

What is the expected behavior?

The REPL to load normally and be usable

What do you see instead?

Welcome to Bun v1.3.4
Type ".help" for more information.
[!] Please note that the REPL implementation is still experimental!
    Don't consider it to be representative of the stability or behavior of Bun overall.
> [ws/message] An unexpected error occured: Received message for unknown request ID: undefined
Received Data: {"method":"Console.messageAdded","params":{"message":{"source":"console-api","level":"log","text":"Welcome to Bun v1.3.4\nType \".help\" for more information.","type":"log","line":580,"column":18,"url":"C:\\Users\\ASUS\\AppData\\Local\\Temp\\bunx-1771422724-bun-repl@latest\\node_modules\\bun-repl\\src\\repl.ts","repeatCount":1,"timestamp":1765098630.285894,"parameters":[{"type":"string","value":"Welcome to Bun v1.3.4\nType \".help\" for more information."}],"stackTrace":{"callFrames":[{"functionName":"start","url":"C:\\Users\\ASUS\\AppData\\Local\\Temp\\bunx-1771422724-bun-repl@latest\\node_modules\\bun-repl\\src\\repl.ts","scriptId":"2","lineNumber":580,"columnNumber":18},{"functionName":"processTicksAndRejections","url":"","scriptId":"3","lineNumber":7,"columnNumber":39}]}}}}
[ws/message] An unexpected error occured: Received message for unknown request ID: undefined
Received Data: {"method":"Console.messageAdded","params":{"message":{"source":"console-api","level":"warning","text":"\u001b[33m\u001b[2m[!] Please note that the REPL implementation is still experimental!\n    Don't consider it to be representative of the stability or behavior of Bun overall.\u001b[0m","type":"log","line":582,"column":19,"url":"C:\\Users\\ASUS\\AppData\\Local\\Temp\\bunx-1771422724-bun-repl@latest\\node_modules\\bun-repl\\src\\repl.ts","repeatCount":1,"timestamp":1765098630.2862303,"parameters":[{"type":"string","value":"\u001b[33m\u001b[2m[!] Please note that the REPL implementation is still experimental!\n    Don't consider it to be representative of the stability or behavior of Bun overall.\u001b[0m"}],"stackTrace":{"callFrames":[{"functionName":"start","url":"C:\\Users\\ASUS\\AppData\\Local\\Temp\\bunx-1771422724-bun-repl@latest\\node_modules\\bun-repl\\src\\repl.ts","scriptId":"2","lineNumber":582,"columnNumber":19},{"functionName":"processTicksAndRejections","url":"","scriptId":"3","lineNumber":7,"columnNumber":39}]}}}}
[ws/message] An unexpected error occured: Received message for unknown request ID: undefined
Received Data: {"method":"Console.messageAdded","params":{"message":{"source":"console-api","level":"error","text":"[ws/message] An unexpected error occured:","type":"log","line":135,"column":22,"url":"C:\\Users\\ASUS\\AppData\\Local\\Temp\\bunx-1771422724-bun-repl@latest\\node_modules\\bun-repl\\src\\repl.ts","repeatCount":1,"timestamp":1765098630.293049,"parameters":[{"type":"string","value":"[ws/message] An unexpected error occured:"},{"type":"string","value":"Received message for unknown request ID: undefined"},{"type":"string","value":"\nReceived Data:"},{"type":"string","value":"{\"method\":\"Console.messageAdded\",\"params\":{\"message\":{\"source\":\"console-api\",\"level\":\"log\",\"text\":\"Welcome to Bun v1.3.4\\nType \\\".help\\\" for more information.\",\"type\":\"log\",\"line\":580,\"column\":18,\"url\":\"C:\\\\Users\\\\ASUS\\\\AppData\\\\Local\\\\Temp\\\\bunx-1771422724-bun-repl@latest\\\\node_modules\\\\bun-repl\\\\src\\\\repl.ts\",\"repeatCount\":1,\"timestamp\":1765098630.285894,\"parameters\":[{\"type\":\"string\",\"value\":\"Welcome to Bun v1.3.4\\nType \\\".help\\\" for more information.\"}],\"stackTrace\":{\"callFrames\":[{\"functionName\":\"start\",\"url\":\"C:\\\\Users\\\\ASUS\\\\AppData\\\\Local\\\\Temp\\\\bunx-1771422724-bun-repl@latest\\\\node_modules\\\\bun-repl\\\\src\\\\repl.ts\",\"scriptId\":\"2\",\"lineNumber\":580,\"columnNumber\":18},{\"functionName\":\"processTicksAndRejections\",\"url\":\"\",\"scriptId\":\"3\",\"lineNumber\":7,\"columnNumber\":39}]}}}}"}],"stackTrace":{"callFrames":[{"functionName":"","url":"C:\\Users\\ASUS\\AppData\\Local\\Temp\\bunx-1771422724-bun-repl@latest\\node_modules\\bun-repl\\src\\repl.ts","scriptId":"2","lineNumber":135,"columnNumber":22}]}}}}
[ws/message] An unexpected error occured: Received message for unknown request ID: undefined
Received Data: {"method":"Console.messageAdded","params":{"message":{"source":"console-api","level":"error","text":"[ws/message] An unexpected error occured:","type":"log","line":135,"column":22,"url":"C:\\Users\\ASUS\\AppData\\Local\\Temp\\bunx-1771422724-bun-repl@latest\\node_modules\\bun-repl\\src\\repl.ts","repeatCount":1,"timestamp":1765098630.2935696,"parameters":[{"type":"string","value":"[ws/message] An unexpected error occured:"},{"type":"string","value":"Received message for unknown request ID: undefined"},{"type":"string","value":"\nReceived Data:"},{"type":"string","value":"{\"method\":\"Console.messageAdded\",\"params\":{\"message\":{\"source\":\"console-api\",\"level\":\"warning\",\"text\":\"\\u001b[33m\\u001b[2m[!] Please note that the REPL implementation is still experimental!\\n    Don't consider it to be representative of the stability or behavior of Bun overall.\\u001b[0m\",\"type\":\"log\",\"line\":582,\"column\":19,\"url\":\"C:\\\\Users\\\\ASUS\\\\AppData\\\\Local\\\\Temp\\\\bunx-1771422724-bun-repl@latest\\\\node_modules\\\\bun-repl\\\\src\\\\repl.ts\",\"repeatCount\":1,\"timestamp\":1765098630.2862303,\"parameters\":[{\"type\":\"string\",\"value\":\"\\u001b[33m\\u001b[2m[!] Please note that the REPL implementation is still experimental!\\n    Don't consider it to be representative of the stability or behavior of Bun overall.\\u001b[0m\"}],\"stackTrace\":{\"callFrames\":[{\"functionName\":\"start\",\"url\":\"C:\\\\Users\\\\ASUS\\\\AppData\\\\Local\\\\Temp\\\\bunx-1771422724-bun-repl@latest\\\\node_modules\\\\bun-repl\\\\src\\\\repl.ts\",\"scriptId\":\"2\",\"lineNumber\":582,\"columnNumber\":19},{\"functionName\":\"processTicksAndRejections\",\"url\":\"\",\"scriptId\":\"3\",\"lineNumber\":7,\"columnNumber\":39}]}}}}"}],"stackTrace":{"callFrames":[{"functionName":"","url":"C:\\Users\\ASUS\\AppData\\Local\\Temp\\bunx-1771422724-bun-repl@latest\\node_modules\\bun-repl\\src\\repl.ts","scriptId":"2","lineNumber":135,"columnNumber":22}]}}}}
...

If I hadn't manually Ctrl+C'd the program, garbled output with lots of backslashes will overwhelm the buffer,

Additional information

No response

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🔗 Similar & Duplicate Issues

Related Issues

• oven-sh/bun#20584
• oven-sh/bun#22864

🔗 Related PRs

#23184 - Fix Windows crash in process.title when console title is empty [merged] | src/bun.js/bindings/BunProcess.cpp:
"""

AI-generated summary of changes

• Changes the behavior of BunProcess.cpp's processTitle getter: initializes the title buffer to an empty string before calling uv_get_process_title, and changes the condition to treat either a failure of uv_get_process_title or an empty title as an indication to return "bun" instead of the actual title. This affects control flow by introducing an additional failure/sentinel check and alters the returned value when the title is unavailable or empty.

Alterations to the declarations of exported or public entities

• None

Estimated code review effort: Medium
"""

---

test/regression/issue/23183.test.ts:
"""

AI-generated summary of changes

Adds regression tests for issue 23183 to ensure accessing process.title does not crash on Windows. Introduces two tests using Bun.spawn to execute a small script that prints process.title, verifying:

• no stderr output
• exit code 0
• first test: stdout is the string "string"
• second test: stdout is a non-empty title; for Windows, allows any string, otherwise expects "bun"

No public API changes; tests rely on Bun and harness utilities.

Alterations to the declarations of exported or public entities

Estimated code review effort: Medium
"""

👤 Suggested Assignees

• liquancss
• iann838
• robobun

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[github-actions]

Found 1 possible duplicate issue:

1. Bun REPL in VS Code terminal on Windows outputs error #17567

This issue will be automatically closed as a duplicate in 3 days.

• If your issue is a duplicate, please close it and 👍 the existing issue instead
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