Affected versions

• 88.0a1 (20210304215542)
• 87.0b6 (20210304190020)
• 86.0 (20210222142601)

Affected platforms

• macOS 10.12.6

Steps to reproduce

1. Open Firefox and http://foersom.com/net/HowTo/data/OoPdfFormExample.pdf.
2. Click Print from the hamburger menu.

Expected result

• Print Preview is opened and the PDF is displayed.

Actual result

• Sometimes only a white page is displayed.

Regression range

• I will search for one ASAP.

Notes

• Attached a screenshot with the issue and the error displayed in the web console.
• The issue is not reproducible on Windos10 x64, macOS 10.15 and Ubuntu 20.

I can't reproduce on linux (debian) and nightly.
According to the bt on the screenshot, I'd say the afterprint event is triggered too soon.
:emilio, does that ring a bell ?

Afterprint doesn't wait for the PDF to finish rendering, and it never has, afaict. Printing with mozPrintCallbacks is async

Alexandru, could you find the regression range?

(In reply to Marco Castelluccio [:marco] from comment #3)

Alexandru, could you find the regression range?

Apologies for the late response here. Looked over this today and I noticed the following on macOS 10.12:

• the issue is still reproducing with Firefox 95.0.1 but not with 96.0b6 or 97.0a1 (20211217035153)
• on 95.0.1 I am still hitting slow loads on print preview (bug 1679506), but this is fixed with 96.0b6 and the latest Nightly. Print preview and saving to PDF happens almost instantly.

I have made a -find-fix search with mozregression and this is the pushlog:
https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=08ce6b6c9b403f422f2b6988e6e3548f1c27b24a&tochange=71e0096135267932444eaa4f7cfdda5560fb9446. If regression range is still needed please let me know, but it will be harder to search because of bug 1679506.