1617531 - Pretty-print button is not always displayed for minified javascript files in Firefox Developer Edition 74.0b (64-bit)

Status: RESOLVED DUPLICATE of bug 1555307

(DevTools :: Debugger, defect, P3)

Description

[SorPos]

Attachment: 2020-02-24 screenshot firefox pretty-print not displayed.png

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:74.0) Gecko/20100101 Firefox/74.0

Steps to reproduce:

Open the following webpage in Firefox Developer Edition 74.0b6 (64-bit) on Windows 10:
https://ec.europa.eu/programmes/erasmus-plus/projects/eplus-project-details/#project/2018-1-AT01-KA116-038883

Press F12 and go to the Debugger tab.
In the Sources tree, expand the following path: ec.europa.eu -> programmes -> valor/dist -> then double-click to open the file erasmus-plus-5.9.0-prod-drupal.min.js

Actual results:

The file erasmus-plus-5.9.0-prod-drupal.min.js is opened in the Source debugger, but the "Pretty-print" button is not visible, even though this is a minified javascript file. Only the "Blackbox source" button is visible.

Expected results:

The "Pretty-print" button ({}) should also be visible, to allow me to expand the minified file, as available for other files on other websites.

Comment 1

[BugBot [:suhaib / :marco/ :calixte]]

Bugbug thinks this bug should belong to this component, but please revert this change in case of error.

Comment 2

[BugBot [:suhaib / :marco/ :calixte]]

The priority flag is not set for this bug.
:jlast, could you have a look please?

For more information, please visit auto_nag documentation.

Comment 3

[Jan Honza Odvarko [:Honza] (always need-info? me)]

I can easily reproduce the bug using STRs from comment #0

Honza

Comment 4

[:Harald Kirschner :digitarald]

(clearing ni)

Comment 5

[David Walsh :davidwalsh]

Looking at this briefly, I see the file ends with //# sourceMappingURL=erasmus-plus-5.9.4-prod-drupal.min.js.map and the following is returning true:

prefs.clientSourceMapsEnabled && isSourceWithMap(state, id)

Thus our canPrettyPrintSource is returning false and we don't show the icon.

Comment 6

[Rob Wu [:robwu]]

Duplicate of bug 1555307, same root cause: https://bugzilla.mozilla.org/show_bug.cgi?id=1555307#c2