Bug 225394

Summary:

document is slow to change location when URL loaded from address bar (process swapping?)

Product:

WebKit

Reporter:

Jeff Johnson <opendarwin>

Component:

Page Loading

Assignee:

Nobody <webkit-unassigned>

Status:

NEW ---

Severity:

Normal

CC:

achristensen, ap, beidson, cdumez, timothy, webkit-bug-importer

Priority:

Keywords:

InRadar

Version:

Safari 14

Hardware:

Mac (Apple Silicon)

OS:

macOS 11

Attachments:

Description	Flags
Sample HTML demonstrating the bug	none

Description Jeff Johnson 2021-05-05 08:48:53 PDT

Created attachment 427769 [details]
Sample HTML demonstrating the bug

Overview:
Sorry I don't have a great title for this bug. The bug is that when a URL is loaded from the address bar (with the web inspector closed), the document location can be slow to change (commit). I demonstrate the bug by calling window.stop() in a <script> element in <head>.

This technique is just a way to demonstrate the bug; of course you wouldn't typically call window.stop() in these circumstances (but who knows). The way I discovered the bug was actually by working on a Safari app extension. I noticed that SFSafariTab methods such as close and navigateToURL failed to do anything if I called them very early in the page loading. This led me to investigate the cause of the bug, which appears to be in Safari itself rather than in the extension API. The extension bug is just a consequence of the Safari bug.

Steps to Reproduce:
1) Download attached "index.html" file
2) In Terminal, cd Downloads
3) In Terminal, /usr/bin/python -m SimpleHTTPServer 8000
4) Open new Safari tab (don't open web inspector)
5) In address bar, enter http://localhost:8000
6) Open JavaScript console

Actual Results:
Console should log "before" and "after", and window.location should be http://localhost:8000

Expected Results:
Console log is empty, and window.location is about:blank

Build Date & Hardware:
Safari 14.1 (16611.1.21.161.6) on macOS 11.3.1 (20E241) with Mac mini M1

Additional Builds and Platforms:
Safari 14.1 (14611.1.21.161.7) on macOS 10.14.6 (18G9028) with Intel MacBook Pro

Additional Information:
The bug does not occur if you open the web inspector before you load the page from the address bar. The bug also does not occur if you call "open http://localhost:8000" from Terminal.

Note that the bug occurs even when the previous page in not about:blank. For example, if you first load https://www.apple.com/ and then http://localhost:8000, the window.location will still be apple.com even though Safari has clearly loaded index.html and executed its script.

Comment 1 Jeff Johnson 2021-05-05 09:54:21 PDT

It appears that you can just load the sample HTML directly from this bug report rather than needing to download it and run SimpleHTTPServer.

Comment 2 Alexey Proskuryakov 2021-05-06 18:12:00 PDT

Could you please confirm if expected and actual results aren't swapped above? When I attempt to reproduce, I get the "expected result" in Safari, but "actual result" in Chrome.

Comment 3 Jeff Johnson 2021-05-06 18:29:43 PDT

(In reply to Alexey Proskuryakov from comment #2)
> Could you please confirm if expected and actual results aren't swapped
> above? When I attempt to reproduce, I get the "expected result" in Safari,
> but "actual result" in Chrome.

You're correct, I accidentally swapped expected and actual.

Comment 4 Alexey Proskuryakov 2021-05-07 10:44:57 PDT

Thank you for the report!

If you have any additional details on how this impacts development (for example, if workarounds degrade customer experience), those would help with prioritization.

Comment 5 Radar WebKit Bug Importer 2021-05-07 10:45:17 PDT

<rdar://problem/77662673>