PDF - yellow fallback bar doesn't appear below URL bar on some files/links

[cfogelSV]

Affected versions

• 81.0b3, 81.0b4, 82.0a1 (2020-08-30);

Affected platforms

• macOS 11.0, Windows 10, macOS 10.15

Steps to reproduce

• pdfjs.renderInteractiveForms - true

1. Launch Firefox;
2. Access links such as: 1, 2;
3. Click inside the page - on any form;

Expected result

• yellow fallback bar should appear below URL bar;

Actual result

• fallback bar not displayed;

Regression range

• First bad: 2020-08-12;
• Last good: 2020-08-13;
• Pushlog: link;
• Potential regressor: 1658934

Additional notes

• S2 as suggested severity.

[Snuffleupagus]

yellow fallback bar should appear below URL bar;

No it shouldn't, since those forms contain functionality that's now supported; this the expected result of PR #12271 (which fixed issue #12217, that you filed :-)

[cfogelSV]

Ok on that par. Thanks for the confirmation.

For irs.gov it still appears.
It's a bit unclear, as per notes in the 1661338 uplift the yellow bar is expected to be displayed.

Is it scripted different or does that form is of a different type?
If so, what are the key differences that we should look after from this point on?

[Snuffleupagus]

It's a bit unclear, as per notes in the 1661338 uplift the yellow bar is expected to be displayed.

Are you perhaps referring to https://bugzilla.mozilla.org/show_bug.cgi?id=1661338#c5?
If so, that simply fixed a regression that prevented the "Open With Different Viewer"-button from working if and only if the fallback bar is displayed, it does not at all imply that the fallback bar should be unconditionally displayed for all forms.

Is it scripted different or does that form is of a different type?

Please refer to #12271 (comment), and the commit messages in that PR for additional details.
Admittedly this is all pretty technical, and just opening a PDF document isn't usually enough to determine exactly what sort of form data it may contain (you really need to look at the actual data-structure of the PDF document itself).

If so, what are the key differences that we should look after from this point on?

This is what determines if the fallback bar is displayed, when encountering forms:

pdf.js/web/app.js

Lines 1445 to 1454 in aa27e7f

	if (info.IsXFAPresent && !info.IsAcroFormPresent) {
	console.warn("Warning: XFA is not supported");
	this._delayedFallback(UNSUPPORTED_FEATURES.forms);
	} else if (
	(info.IsAcroFormPresent || info.IsXFAPresent) &&
	!this.pdfViewer.renderInteractiveForms
	) {
	console.warn("Warning: Interactive form support is not enabled");
	this._delayedFallback(UNSUPPORTED_FEATURES.forms);
	}

For an individual PDF document, after loading it, executing PDFViewerApplication.documentInfo in the web-console shows you the corresponding values here.

[cfogelSV]

Thanks again for clearing it out.
Closing this report.