fix(mcp): surface unhandled rejections instead of crashing the server#40452
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pavelfeldman merged 2 commits intomicrosoft:mainfrom Apr 28, 2026
Merged
fix(mcp): surface unhandled rejections instead of crashing the server#40452pavelfeldman merged 2 commits intomicrosoft:mainfrom
pavelfeldman merged 2 commits intomicrosoft:mainfrom
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Capture process-level unhandled rejections in Context and append them to the next tool response, so a user-installed callback (e.g. a page.route handler) that throws asynchronously no longer tears down the MCP transport. Fixes: microsoft/playwright-mcp#1572
yury-s
approved these changes
Apr 27, 2026
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Awaiting __fn__ alone deadlocks when a user-installed callback (e.g. a page.route handler) throws asynchronously: page.evaluate keeps waiting for the orphaned route, the IIFE never settles, and the tool hangs until the test/action timeout. Subscribe to Context's unhandledRejection feed inside runCode and reject __end__ to break out, while the Context-level handler still records the rejection for the response.
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Test results for "MCP"3 failed 6805 passed, 927 skipped Merge workflow run. |
This was referenced May 1, 2026
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Summary
unhandledRejectionevents in the MCPContextand surface them on the next tool response, so a user-installed callback (e.g. apage.routehandler) that throws asynchronously no longer tears down the MCP transport.Fixes microsoft/playwright-mcp#1572