1522989 - Headless mode doesn't work with screenshot

Status: RESOLVED FIXED

(Firefox :: Headless, defect)

Description

[thomasmo]

Looks like the fix to Bug 1507352 breaks capturing a screenshot in headless mode, at least with the command in the repro steps below. Removing the fix enables the fix again.

Repro Steps:

In a build that contains https://phabricator.services.mozilla.com/D11969 (Fx 65+), execute the following command:
firefox.exe -headless -no-remote -profile c:\path\to\profile -screenshot c:\path\to\screenshot.jpg https://eggtimer.org

• Expected: screenshot written to disk at c:\path\to\screenshot.jpg, firefox.exe (all of them) terminate
• Actual: no screenshot written to disk, firefox.exe stays open with cpu idle

Comment 1

[Dave Townsend [:mossop]]

I wonder if we'd be better off using this to avoid the about:blank load: https://searchfox.org/mozilla-central/source/docshell/base/nsIDocShell.idl#944

Comment 2

[(no longer active)]

Can you add a debugging statement here: https://searchfox.org/mozilla-central/rev/465dbfe030dfec7756b9b523029e90d48dd5ecce/browser/components/shell/HeadlessShell.jsm#36 to print out what uri and location are? For example, something like:

  dump(`uri is: ${uri.spec} and location is ${location.spec}\n`);

Comment 3

[(no longer active)]

(In reply to Dave Townsend [:mossop] (he/him) from comment #1)

I wonder if we'd be better off using this to avoid the about:blank load: https://searchfox.org/mozilla-central/source/docshell/base/nsIDocShell.idl#944

We probably can, but it would be hard to code that since the docshell would live in the content process...

Comment 4

[thomasmo]

Here is the debug output where that code is:
uri is: undefined and location is https://eggtimer.org/

Comment 5

[(no longer active)]

Oh, I'm sorry. I had a typo in my previous debug code. What I should have said was:

 dump(`uri is: ${uri} and location is ${location.spec}\n`);

My mistake caused the first result to come out as undefined. Any chance you could try this please?

Comment 6

[(no longer active)]

My guess is that uri would be "https://eggtimer.org" (without the trailing slash)!

Comment 7

[(no longer active)]

Attachment: Bug 1522989 - Only compare URI specs against parsed URI specs;

Comment 8

[(no longer active)]

If my guess is correct, https://phabricator.services.mozilla.com/D17710 should fix the bug.

Comment 9

[thomasmo]

D'oh! I didn't catch that either. Here's the update:
uri is: https://eggtimer.org and location is https://eggtimer.org/

Yes--the trailing slash makes the difference

Comment 10

[(no longer active)]

Great, I'd appreciate if you can try out the patch above. It should fix the problem, I'm pretty sure.

Comment 11

[thomasmo]

Yes--I can confirm that the patch fixes this bug

Comment 12

[(no longer active)]

Thanks very much!

Comment 13

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/34e24b0fb7b7
Only compare URI specs against parsed URI specs; r=mossop

Comment 14

[Dorel Luca [:dluca]]

Backed out changeset 34e24b0fb7b7 (bug 1522989) for ESLint failure

Log:
https://treeherder.mozilla.org/logviewer.html#/jobs?job_id=224173570&repo=autoland&lineNumber=276

Push with failures:
https://treeherder.mozilla.org/#/jobs?repo=autoland&revision=34e24b0fb7b7296e7a4b928dd217b15d2f0d96ac&selectedJob=224173570

Backout:
https://hg.mozilla.org/integration/autoland/rev/33ca2ea6b37064d12c0d4fefc81bf689396a5e57

Comment 15

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/29da27d7e834
Only compare URI specs against parsed URI specs; r=mossop

Comment 16

[Cristian Brindusan [:cbrindusan]]

https://hg.mozilla.org/mozilla-central/rev/29da27d7e834