Python Lab: pyodide on separate domain behind experiment#73741
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bencodeorg
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bencodeorg
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Jul 14, 2026
| # every module in an eval() call for source maps -- wasm-unsafe-eval doesn't cover | ||
| # that, only actual eval() does. Minified/production builds use devtool: 'source-map' | ||
| # instead, which doesn't need this. | ||
| script_src += " 'unsafe-eval'" |
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I had issues running the new sandboxed version via yarn start (although yarn start:cheapest worked because it doesn't have source maps), as well as on Drone (when I had the experiment enabled by default) without this. I'm not sure if there's a better approach here, so could use a second pair of eyes.
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We also allow this on any version of the web lab 2 preview, so I think it's ok.
molly-moen
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Jul 17, 2026
| # every module in an eval() call for source maps -- wasm-unsafe-eval doesn't cover | ||
| # that, only actual eval() does. Minified/production builds use devtool: 'source-map' | ||
| # instead, which doesn't need this. | ||
| script_src += " 'unsafe-eval'" |
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We also allow this on any version of the web lab 2 preview, so I think it's ok.
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(extends work and copies description from this PR, but puts it behind an experiment. New layer is
pyodideManager, which chooses between the old and new approach based on an experiment flag.): #73653Sets up Python Lab such that the core execution (Web Worker running pyodide) happens on a separate domain behind an experiment. Can be turned on with the URL param
?pythonlab-separate-domain=1.The implementation is very similar to what we do in Web Lab 2.
Testing story
I tested manually that I could run Python Lab programs with and without the experiment enabled, and I only observed the sandbox iframe added to the DOM with the experiment enabled.
Follow-up work
There's some initial work that was done to support network requests in Python Lab that has been on pause: https://codedotorg.atlassian.net/browse/CT-537
I did some exploration here just to validate that I could get GET requests working with pyodide running on the separate domain if wanted to add that eventually, which was successful (although worth investigating in more detail). More information here: https://codedotorg.slack.com/archives/C03DBDN67B7/p1784142244745509?thread_ts=1783019149.114019&cid=C03DBDN67B7