Modified form save data warning dismissed if users chooses to print/save but the action is canceled

[bogdanmaris]

Affected versions

• Firefox 81.0b2
• Latest Nightly 82.0a1

Affected platforms

• Windows 10 64bit
• MacOS 10.15.6
• Ubuntu 18.04 64bit

Steps to reproduce

1. Open a pdf with form (eg: https://www.irs.gov/pub/irs-pdf/f1040.pdf)
2. Enter some text in a random field
3. Click the print button inside pdf/Hit CTRL+S
4. Cancel the print action/save action
5. Reload/close the tab with the pdf

Expected result

• Save notification message is still there since user did not print/save the page.

Actual result

• Save notification message is not displayed anymore and the data is lost upon reloading/closing the tab

Regression range

• First bad: 79f9ec2f6fece69848aefefb9300fa3d35aa5593
• Last good: 9877228c87db0fe7f1dd353ff8bc5981f52d8622
• Pushlog: https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=9877228c87db0fe7f1dd353ff8bc5981f52d8622&tochange=79f9ec2f6fece69848aefefb9300fa3d35aa5593
• Potential regressor: Bug 1660617 - Update pdf.js to version 2.6.302 / Don't warn when navigating away from a modified form, if printing has occurred (issue 12262) #12265

Additional notes

• Also logged in bugzilla: https://bugzilla.mozilla.org/show_bug.cgi?id=1661207

Suggested severity

• I my opinion this should have the S2 severity since we are dealing with data loss.

[Snuffleupagus]

Cancel the print action/save action
[...]
Save notification message is not displayed anymore and the data is lost upon reloading/closing the tab

That's a known problem, which is even explicitly mentioned in #12265 (comment), and in general it's probably going to very difficult to detect those cases.

Potential regressor: Bug 1660617 - Update pdf.js to version 2.6.302 / #12265

Sorry, but this doesn't really make sense, and as mentioned in that PR the "cancelling of saving"-case already didn't work prior to that.

Also logged in bugzilla: https://bugzilla.mozilla.org/show_bug.cgi?id=1661207

Edit: Also, filing the same issue in two places will only make tracking bugs more difficult.

[timvandermeij]

We would be happy to address this, but I don't think there is any way for us to know if printing/saving succeeded in general and across browsers.

[timvandermeij]

Closing since I don't know of any way we can know this, especially across browsers. The upstream issue will remain open for any ideas, but for now this is not actionable.