Add chunk type checking of requestForServiceWorker's body's stream

[yoichio]

• At least two implementers are interested (and none opposed):
  • Chrome
  • Firefox
• Tests are written and can be reviewed and commented upon at:
  • Add FetchEvent test that should reject none Uint8Array ReadableStream. web-platform-tests/wpt#28203
• Implementation bugs are filed:
  • Chrome: https://bugs.chromium.org/p/chromium/issues/detail?id=1191310
  • Firefox: N/A as streaming request body has not been implemented.
  • Safari: N/A as streaming request body has not been implemented.

(See WHATWG Working Mode: Changes for more details.)

This change addresses the inconsistency discussed in #267 that a chunk type in stream body on uploading to the network is
limited only to Uint8Array but passing it to a service worker is not restricted.
This PR changes later to limiting Uint8Array as well.

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Preview | Diff

[yoichio]

Ping?

[yutakahirano]

Please see https://github.com/whatwg/fetch#formatting for the formatting rules (and add missing rules if there are).

[annevk]

Looks good to me modulo nits. Is everyone else happy with this as well. @ricea?

[ricea]

lgtm

[annevk]

Tentative commit message:

Check chunk type of body's stream when passed to a service worker

Tests: https://github.com/web-platform-tests/wpt/pull/28203

@yoichio it's not clear to me how this fixes #267 as we still don't use BYOB streams, right? It sounds like that only matters for responses so doesn't block upload streams, but it's still something that needs to be done?

[ricea]

I wonder if it's too strict? Do implementations accept other types than Uint8Array?

For comparison, a readable byte stream will accept any kind of ArrayBufferView and convert it to a Uint8Array.

[annevk]

For response streams I think all implementations have this restriction. Request streams are a "new" feature that's still being developed. As mentioned in #267 we decided on the current restriction in yutakahirano/fetch-with-streams#53, but as mentioned there we could revisit it. If we want to do that let's do it through a new issue though and make the change for all streams.

[yoichio]

Updated the description.

[ricea]

For response streams I think all implementations have this restriction. Request streams are a "new" feature that's still being developed. As mentioned in #267 we decided on the current restriction in yutakahirano/fetch-with-streams#53, but as mentioned there we could revisit it. If we want to do that let's do it through a new issue though and make the change for all streams.

Okay, thanks for the background!

[annevk]

Thanks @yoichio! And thanks @ricea for the review.