Using Safari Version 12.1 (14607.1.40.1.4) and the latest Safari Technology Preview (Release 80 (Safari 12.2, WebKit 14608.1.16)) on macOS 10.14.4, I am unable to run pyodide examples (though other iodide examples work). Pyodide fetches a WASM archive with Python + scientific packages cross-compiled to WebAssembly, and uses them to execute Python in the browser. For context, see https://hacks.mozilla.org/2019/04/pyodide-bringing-the-scientific-python-stack-to-the-browser/ . The only error that appears in the (devtools) console when I try to run a %% py block is [Error] Unhandled Promise Rejection: undefined (anonymous function) rejectPromise promiseReactionJob I carved out a subset of one of the Pyodide examples that reproduces this behavior here: https://alpha.iodide.io/notebooks/2154/ (Click in text field after '%% py' and "Shift-Enter" to execute.) Corresponding Pyodide bug: https://github.com/iodide-project/pyodide/issues/402 It's entirely possible this is a Pyodide bug that is being obscured by the default behavior in Firefox and Chrome, but I cannot find anywhere in the Safari Dev Tools that will expose what exactly is happening. Another pair of eyes on this would be very helpful! Thanks in advance.
Also present in today's Safari Technology Preview Release 81.
The underlying issue was a call to WebAssembly.compileStreaming, which is not (yet) available on Safari. I'm not sure why this was not visible from the traceback, but a debug / non-minified build showed the culprit. Closing.
<rdar://problem/50448468>