2073009 - browser_attribution_actor.js opens eight tabs it does not need

Status: RESOLVED FIXED

(Firefox :: New Tab Page, task)

Description

[Florian Quèze [:florian]]

browser_attribution_actor.js runs 16 BrowserTestUtils.withNewTab("https://example.com") cycles. Eight of them exist only so that setAllowList() can call AttributionParent.prototype.setAllowListForTest, which assigns a module-global Set and never touches this, so no tab is needed to call it.

Dropping those eight tabs takes the test from 4.06 s to 3.52 s locally (2 runs before, 5 after, --headless), with the same 14 assertions passing and --verify at 420 passed / 0 failed / 0 unexpected.

Comment 1

[Florian Quèze [:florian]]

Attachment: Bug 2073009 - Stop opening a tab per allowlist reset in browser_attribution_actor.js, r=#home-newtab-reviewers.

setAllowList() opened a tab at https://example.com solely to obtain an
AttributionParent instance and call setAllowListForTest on it. That method
assigns the module-global allowlist and never reads this, so the tab only
doubled the test's tab churn and its content process launches.

Comment 2

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/7bb27b9ebb72
https://hg.mozilla.org/integration/autoland/rev/39445d833a71
Stop opening a tab per allowlist reset in browser_attribution_actor.js, r=mconley.

Comment 3

[Sandor Molnar[:smolnar]]

https://hg.mozilla.org/mozilla-central/rev/39445d833a71

Comment 4

[Performance Sheriff Bot]

Perfherder has detected a talos performance change from push 39445d833a71cc8d3e750ad1bc664bd0dbf15478.

No action is required from the author; this comment is provided for informational purposes only.

Improvement	Test	Platform	Options	Absolute values [old vs new]
5%	tart (doc)	linux2404-64-shippable	e10s fission stylo webrender-sw	2.65 -> 2.51

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Details of the alert can be found in the alert summary, including links to graphs and comparisons for each of the affected tests.