[Webkit-unassigned] [Bug 197472] New: Pyodide WASM bundle fetched but won't load ("Unhandled promise rejection"), works on FF / Chrome

[bugzilla-daemon at webkit.org]

https://bugs.webkit.org/show_bug.cgi?id=197472

            Bug ID: 197472
           Summary: Pyodide WASM bundle fetched but won't load ("Unhandled
                    promise rejection"), works on FF / Chrome
           Product: WebKit
           Version: Safari Technology Preview
          Hardware: Macintosh
                OS: macOS 10.14
            Status: NEW
          Severity: Normal
          Priority: P2
         Component: WebAssembly
          Assignee: webkit-unassigned at lists.webkit.org
          Reporter: jdl at fastmail.com

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.

-- 
You are receiving this mail because:
You are the assignee for the bug.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.webkit.org/pipermail/webkit-unassigned/attachments/20190501/04bbe056/attachment.html>