1479059 - run_at document_start doesn't work

Status: RESOLVED INVALID

(WebExtensions :: General, defect)

Description

[KOLANICH]

document_start scripts don't run before page scripts

1 clone https://github.com/KOLANICH/run_at_document_start_doesnt_work.git
2 read the code
3 install the extension
4 open the page
5 see `broken`

Comment 1

[Kris Maglione [:kmag]]

For executeScript, "run_at" is the earliest point in the load cycle the script will run. The guarantees that it will run before page scripts only apply to statically registered content scripts.

Comment 2

[KOLANICH]

Kris, it neither works for statically, nor for dynamically. See the code. The test checks both cases.

Comment 3

[Kris Maglione [:kmag]]

It very definitely does work for static content scripts

Comment 4

[KOLANICH]

>It very definitely does work for static content scripts

For me it doesn't for most of time. Success is nondeterministic, there is a race. Latest devedition, Win 7, 32 bit.

Comment 5

[Kris Maglione [:kmag]]

This is probably worth looking into, then. We do have tests for this, though, and they pass consistently.

Comment 6

[David Durst [:ddurst]]

If these tests are passing, let's have QA do a pass with this extension to see if the failures are reproducible on known environments.

Comment 7

[Vlad Jiman]

Verified on Nightly (63.0a1) and FF (61.0.1) using Ubuntu and Windows 10 x64 bit. 
The issue is reproducing most of the time, giving the "broken" result, however, in a very low percentage of the cases, test2 will be shown as OK.

Validated using the test addon along with the test html by using multiple refreshes, re-opening the window, new tab, etc.

Comment 8

[Vlad Jiman]

Attachment: record1.mov

Comment 9

[Rob Wu [:robwu]]

The test case is flawed. In manifest.json, you're using "contentScript.js",
but the file itself is called "content_script.js".
When I rename the file to match the name in manifest.json, the test passes in Firefox 61.0.1.

Moreover, for "test2" you are calling tabs.executeScript at the webNavigation.onCommitted event. There is no guarantee that this executeScript method executes before the document attempts to run its scripts.

If you can still manage to reproduce the problem, please mention the following:
- Firefox version and operating system
- Whether the issue also reproduces when you remove the "defer" attribute (and put the script right before </body>).
- Whether the issue happens only at the first page load after an extension is loaded, or whether it also happens when you reload the page.

Comment 10

[Victor Carciu]

I followed suggestions from Rob and everything looks fine now.

Thank you.

Comment 11

[KOLANICH]

I apologize, this was realy my fault, I confirm that the test with statically injected script is really OK after the fix.