1531191 - The DPR setting seems to be broken

Status: RESOLVED INVALID

(DevTools :: Responsive Design Mode, defect, P3)

Description

[(no longer active)]

STR:

1. Go to https://hg.mozilla.org/try/rev/4a3bf26df7bae0df6ca82c20f4eec26d9d8dd09f.
2. Go to responsive design mode view.
3. Switch from the default DPR (2 on my system) to something else (e.g. 1 or 3).

Expected Result: something should change about the rendering of the page.

Actual Result: nothing changes about the rendering of the page.

Comment 1

[Botond Ballo [:botond]]

The "actual results" go back as far as the introduction of the DPR control in Firefox 52.

So, either the feature has never worked, or Ehsan and I are misunderstanding how it's supposed to work :)

Comment 2

[(no longer active)]

Oh then I guess it's not a regression!

Comment 3

[Brad Werth [:bradwerth]]

I believe the DPR widget is only changing the simulated DPR setting for the device, not a zoom level. The expected effects would be changing our media query outcome. I'll confirm that we have tests covering this feature and that it is working as intended.

Comment 4

[Brad Werth [:bradwerth]]

(In reply to Brad Werth [:bradwerth] from comment #3)

I believe the DPR widget is only changing the simulated DPR setting for the device, not a zoom level. The expected effects would be changing our media query outcome. I'll confirm that we have tests covering this feature and that it is working as intended.

I believe that https://searchfox.org/mozilla-central/search?q=%40media&case=false&regexp=false&path=responsive.html shows that we do NOT have test coverage over the behavior of this feature. I'll create some tests.

Comment 5

[Brad Werth [:bradwerth]]

(In reply to Brad Werth [:bradwerth] from comment #4)

I believe that https://searchfox.org/mozilla-central/search?q=%40media&case=false&regexp=false&path=responsive.html shows that we do NOT have test coverage over the behavior of this feature. I'll create some tests.

I was mistaken. https://searchfox.org/mozilla-central/source/devtools/client/responsive.html/test/browser/browser_device_pixel_ratio_change.js tests this by programmatically creating a media query and ensuring it matches under varying conditions as this DPR value is changed interactively. The feature is working as intended, and has adequate tests. I'm closing the bug.