1422918 - sourcemaps in tests regressed, making debugging difficult

Status: RESOLVED FIXED

(Firefox :: New Tab Page, defect, P1)

Description

[Dan Mosedale (:dmosedale, :dmose)]

While trying to debug issues encountered while upgrading Enzyme, it become clear that at sometime in the past few months, sourcemaps in tests stopped working.  This appears to have 
two consequences:

Stacks in the console (eg while running tddmc) are missing the source file, which makes tracking down the exact line that failures are happening on as you iterate painful:

    <ComponentPerfTimer>
      #_maybeSendPaintedEvent
        ✖ should call _sendPaintedEvent if props.initialized is true
          Firefox 57.0.0 (Mac OS X 10.12.0)
        expected true to be false
        AssertionError@node_modules/chai/chai.js:5553:18
        [3]</module.exports/Assertion.prototype.assert@node_modules/chai/chai.js:206:13
        [5]</module.exports/<@node_modules/chai/chai.js:589:5
        addProperty@node_modules/chai/chai.js:4240:22
        [6]</module.exports/assert.isFalse@node_modules/chai/chai.js:2521:5
        @system-addon/test/unit/unit-entry.js:88900:7

It appears to be related to breakpoints in the karma debugging setup not firing.

Bisecting.

Comment 1

[Dan Mosedale (:dmosedale, :dmose)]

https://github.com/mozilla/activity-stream/pull/3869 appears to be the regressing commit.

Comment 2

[Dan Mosedale (:dmosedale, :dmose)]

Got it: the preprocessors array is order-sensitive, and the regressing patch changed the order.  Putting the order back fixes at least the tddmc console output.

Comment 3

[GitHub Bugzilla PR Linker]

Attachment: Link to GitHub pull-request: https://github.com/mozilla/activity-stream/pull/3892

Comment 4

[[github robot]]

Commits pushed to master at https://github.com/mozilla/activity-stream

https://github.com/mozilla/activity-stream/commit/bf570f4a5ec7bf4c4beb523ab458660bf1995da6
fix(tests): make sourcemaps for unit tests work again, fix bug 1422918

https://github.com/mozilla/activity-stream/commit/3c0d0194e63f6b07526c342da4116045445d15b6
Merge pull request #3892 from dmose/sourcemap-fix

Fix Bug 1422918 - make sourcemaps for unit tests work again

Comment 5

[Ed Lee :Mardak]

https://hg.mozilla.org/mozilla-central/rev/75910829e890