lighthouse: "Ni.connect is not a function" when testing in DevTools

Developer’s Note

The fix for this should be released on all Chrome channels:

Stable - 116.0.5845.140 Beta - 117.0.5938.35 Dev - 118.0.5951.0 Canary - 118.0.5939.0

If you are still experiencing this issue, please verify that your Chrome is up to date before reporting.

FAQ

Yes, my issue is not about variability or throttling.
Yes, my issue is not about a specific accessibility audit (file with axe-core instead).

URL

https://mini-project-lighthouse.herokuapp.com/

What happened?

When trying to run an audit, received an error and was unable produce an audit. Sometimes and audit would work, but only the PWA audit report was displayed/created.

What did you expect?

Expected to generate a full audit report. All audit settings selected. Only the PWA section was generated sometimes. Issues replicated in incognito.

What have you tried?

Using latest chrome browser, restarted browser, removed/re-installed extension, and allowed incognito extension use.

How were you running Lighthouse?

WebPageTest

Lighthouse Version

100.0.0

Chrome Version

115.0.5790.102

Node Version

No response

OS

Windows 10

Relevant log output

Ni.connect is not a function

Channel: DevTools
Initial URL: https://mini-project-lighthouse.herokuapp.com/
Chrome Version: 115.0.0.0
Stack Trace: TypeError: Ni.connect is not a function
    at devtools://devtools/bundled/devtools-frontend/front_end/third_party/lighthouse/lighthouse-dt-bundle.js:618:972
    at Runner.gather (devtools://devtools/bundled/devtools-frontend/front_end/third_party/lighthouse/lighthouse-dt-bundle.js:524:349)
    at navigationGather (devtools://devtools/bundled/devtools-frontend/front_end/third_party/lighthouse/lighthouse-dt-bundle.js:618:858)
    at async navigation (devtools://devtools/bundled/devtools-frontend/front_end/third_party/lighthouse/lighthouse-dt-bundle.js:620:940)
    at async i (devtools://devtools/bundled/devtools-frontend/front_end/entrypoints/lighthouse_worker/lighthouse_worker.js?remoteBase=https%3A%2F%2Fchrome-devtools-frontend.appspot.com%2Fserve_file%2F%4090efd4b0ad6aa15eeafcdabd5817ae939f7ba059%2F:1:2668)
    at async self.onmessage (devtools://devtools/bundled/devtools-frontend/front_end/entrypoints/lighthouse_worker/lighthouse_worker.js?remoteBase=https%3A%2F%2Fchrome-devtools-frontend.appspot.com%2Fserve_file%2F%4090efd4b0ad6aa15eeafcdabd5817ae939f7ba059%2F:1:3056)

About this issue

Original URL
State: closed
Created a year ago
Reactions: 21
Comments: 33 (7 by maintainers)

Commits related to this issue

[Lighthouse] Throw if the page handle is null It is possible for the page handle to be null. Lighthouse will still throw an error but it does not reference the actual problem: https://github.com/Goo... — committed to ChromeDevTools/devtools-frontend by adamraine a year ago
[Lighthouse] Use target ID instead of frame ID for target filter Lighthouse bug: https://github.com/GoogleChrome/lighthouse/issues/15300 Bug: None Change-Id: I218372aa27699b2e744813a3ab228f9db3464c2... — committed to ChromeDevTools/devtools-frontend by adamraine a year ago
[M117][Lighthouse] Use target ID instead of frame ID for target filter Lighthouse bug: https://github.com/GoogleChrome/lighthouse/issues/15300 Bug: None Change-Id: I218372aa27699b2e744813a3ab228f9db... — committed to ChromeDevTools/devtools-frontend by adamraine a year ago
[M116][Lighthouse] Use target ID instead of frame ID for target filter Lighthouse bug: https://github.com/GoogleChrome/lighthouse/issues/15300 Bug: 1472050 Change-Id: I218372aa27699b2e744813a3ab228f... — committed to ChromeDevTools/devtools-frontend by adamraine a year ago

Most upvoted comments

I am on Vivaldi, and the error persists.

supersuryaansh on Sep 7, 2023

I am on Vivaldi, and the error persists.

To avoid other Vivaldi users repeating my work, I have filed a report relating to this issue with Vivaldi: VB-99984

dransome on Sep 11, 2023

This started occurring for me after updating to Version 115.0.5790.102 (Official Build) (x86_64), MacOS 13.4, all Lighthouse modes unavailable.

When mode = Navigation:

Ni.connect is not a function

Channel: DevTools
Initial URL: https://xxx
Chrome Version: 115.0.0.0
Stack Trace: TypeError: Ni.connect is not a function
    at devtools://devtools/bundled/devtools-frontend/front_end/third_party/lighthouse/lighthouse-dt-bundle.js:618:972
    at Runner.gather (devtools://devtools/bundled/devtools-frontend/front_end/third_party/lighthouse/lighthouse-dt-bundle.js:524:349)
    at navigationGather (devtools://devtools/bundled/devtools-frontend/front_end/third_party/lighthouse/lighthouse-dt-bundle.js:618:858)
    at async navigation (devtools://devtools/bundled/devtools-frontend/front_end/third_party/lighthouse/lighthouse-dt-bundle.js:620:940)
    at async i (devtools://devtools/bundled/devtools-frontend/front_end/entrypoints/lighthouse_worker/lighthouse_worker.js?remoteBase=https%3A%2F%2Fchrome-devtools-frontend.appspot.com%2Fserve_file%2F%4090efd4b0ad6aa15eeafcdabd5817ae939f7ba059%2F:1:2668)
    at async self.onmessage (devtools://devtools/bundled/devtools-frontend/front_end/entrypoints/lighthouse_worker/lighthouse_worker.js?remoteBase=https%3A%2F%2Fchrome-devtools-frontend.appspot.com%2Fserve_file%2F%4090efd4b0ad6aa15eeafcdabd5817ae939f7ba059%2F:1:3056)

When mode = Timespan, notification of timespan started and you can interact with the page, however on stopping the following is thrown:

Cannot end a timespan before starting one

Channel: DevTools
Initial URL: https://xxx
Chrome Version: 115.0.0.0
Stack Trace: Error: Cannot end a timespan before starting one
    at i (devtools://devtools/bundled/devtools-frontend/front_end/entrypoints/lighthouse_worker/lighthouse_worker.js?remoteBase=https%3A%2F%2Fchrome-devtools-frontend.appspot.com%2Fserve_file%2F%4090efd4b0ad6aa15eeafcdabd5817ae939f7ba059%2F:1:976)
    at self.onmessage (devtools://devtools/bundled/devtools-frontend/front_end/entrypoints/lighthouse_worker/lighthouse_worker.js?remoteBase=https%3A%2F%2Fchrome-devtools-frontend.appspot.com%2Fserve_file%2F%4090efd4b0ad6aa15eeafcdabd5817ae939f7ba059%2F:1:3062)

When mode = Snapshot

Cannot read properties of null (reading ‘target’)

Channel: DevTools
Initial URL: https://xxx
Chrome Version: 115.0.0.0
Stack Trace: TypeError: Cannot read properties of null (reading 'target')
    at Driver.connect (devtools://devtools/bundled/devtools-frontend/front_end/third_party/lighthouse/lighthouse-dt-bundle.js:603:762)
    at snapshotGather (devtools://devtools/bundled/devtools-frontend/front_end/third_party/lighthouse/lighthouse-dt-bundle.js:621:282)
    at async snapshot (devtools://devtools/bundled/devtools-frontend/front_end/third_party/lighthouse/lighthouse-dt-bundle.js:621:88)
    at async i (devtools://devtools/bundled/devtools-frontend/front_end/entrypoints/lighthouse_worker/lighthouse_worker.js?remoteBase=https%3A%2F%2Fchrome-devtools-frontend.appspot.com%2Fserve_file%2F%4090efd4b0ad6aa15eeafcdabd5817ae939f7ba059%2F:1:2446)
    at async self.onmessage (devtools://devtools/bundled/devtools-frontend/front_end/entrypoints/lighthouse_worker/lighthouse_worker.js?remoteBase=https%3A%2F%2Fchrome-devtools-frontend.appspot.com%2Fserve_file%2F%4090efd4b0ad6aa15eeafcdabd5817ae939f7ba059%2F:1:3056)

lucasnetau on Jul 26, 2023

SOLVED (for me) - by restarting Chrome.

Good to know

Running in a Private tab works best
I found that having multiple Private tabs can cause this problem too - so you may want to check for other tabs running Lighthouse

ScottAgirs on Aug 24, 2023

Hi. Dev here.

We’re having trouble reproducing this so… if you want to poke around… we’d appreciate some more debugging details.

Unfortunately since we run lighthouse in a webworker… this is not trivial debugging.

undock devtools. ctrl-shift-i to inspect devtools. now you have devtools on devtools (we’ll call this DoD). optionally redock the first devtools.
in DoD, ctrl-o and look for lighthouse.js place a breakpoint within initWorker’s onmessage callback
in page DevTools, start Lighthouse with ‘Analyze Page Load’ the DoD debugger should pause on your new breakpoint
You can now remove the breakpoint (otherwise it’ll get annoying)
you should also now see a lighthouse_worker.js in DoD threads now:
in the DoD, ctrl-o for puppeteer.js, go to the very bottom and place a breakpoint on the return statement:
resume script execution. you should pause on the new breakpoint
log out e
log out l.pages().then(pages => console.warn(pages.length))
resume and view the last log

A e.mainFrameId that’s undefined/null would be a problem And… a length of 0 would also be very surprising. But… both might indicate the problem.

Thanks

paulirish on Aug 7, 2023

I’m running into the same error on 115.0.5790.114

frankli0324 on Jul 28, 2023

same as above. now have Mi.connect is not a function error

Channel: DevTools
Initial URL: <some_url>
Chrome Version: 116.0.0.0
Stack Trace: TypeError: Mi.connect is not a function
    at devtools://devtools/bundled/devtools-frontend/front_end/third_party/lighthouse/lighthouse-dt-bundle.js:624:662
    at Runner.gather (devtools://devtools/bundled/devtools-frontend/front_end/third_party/lighthouse/lighthouse-dt-bundle.js:527:132)
    at navigationGather (devtools://devtools/bundled/devtools-frontend/front_end/third_party/lighthouse/lighthouse-dt-bundle.js:624:548)
    at async navigation (devtools://devtools/bundled/devtools-frontend/front_end/third_party/lighthouse/lighthouse-dt-bundle.js:626:696)
    at async i (devtools://devtools/bundled/devtools-frontend/front_end/entrypoints/lighthouse_worker/lighthouse_worker.js?remoteBase=https%3A%2F%2Fchrome-devtools-frontend.appspot.com%2Fserve_file%2F%401a391816688002153ef791ffe60d9e899a71a037%2F:1:2668)
    at async self.onmessage (devtools://devtools/bundled/devtools-frontend/front_end/entrypoints/lighthouse_worker/lighthouse_worker.js?remoteBase=https%3A%2F%2Fchrome-devtools-frontend.appspot.com%2Fserve_file%2F%401a391816688002153ef791ffe60d9e899a71a037%2F:1:3056)

MacOS 13.4.1

metoo,MacOs 12.5 ,Chrome version 116.0.5845.96

left0ver on Aug 22, 2023

The same error (incognito or not - doesn’t matter)

Mi.connect is not a function

Channel: DevTools
Initial URL: <some_url>
Chrome Version: 116.0.0.0
Stack Trace: TypeError: Mi.connect is not a function
    at devtools://devtools/bundled/devtools-frontend/front_end/third_party/lighthouse/lighthouse-dt-bundle.js:624:662
    at Runner.gather (devtools://devtools/bundled/devtools-frontend/front_end/third_party/lighthouse/lighthouse-dt-bundle.js:527:132)
    at navigationGather (devtools://devtools/bundled/devtools-frontend/front_end/third_party/lighthouse/lighthouse-dt-bundle.js:624:548)
    at async navigation (devtools://devtools/bundled/devtools-frontend/front_end/third_party/lighthouse/lighthouse-dt-bundle.js:626:696)
    at async i (devtools://devtools/bundled/devtools-frontend/front_end/entrypoints/lighthouse_worker/lighthouse_worker.js?remoteBase=https%3A%2F%2Fchrome-devtools-frontend.appspot.com%2Fserve_file%2F%401a391816688002153ef791ffe60d9e899a71a037%2F:1:2668)
    at async self.onmessage (devtools://devtools/bundled/devtools-frontend/front_end/entrypoints/lighthouse_worker/lighthouse_worker.js?remoteBase=https%3A%2F%2Fchrome-devtools-frontend.appspot.com%2Fserve_file%2F%401a391816688002153ef791ffe60d9e899a71a037%2F:1:3056)

MacOS, Version 116.0.5845.96 (Official Build) (arm64)

Tilesto on Aug 21, 2023