screenEmulation.mobile errors with must be boolean when provided with a boolean

[samos123]

Steps to reproduce:

1. Run the following

lighthouse https://www.google.com --chrome-flags="--no-sandbox --headless" --output=json --output-path=stdout --disable-dev-shm-usage --form-factor=desktop --throttling.throughputKbps=1000 --throttling.rttMs=0 --throttling.cpuSlowdownMultiplier=1 --throttling.requestLatencyMs=0 --throttling.downloadThroughputKbps=0 --throttling.uploadThroughputKbps=0 --screenEmulation.width=1350 --screenEmulation.height=940 --screenEmulation.deviceScaleFactor=1 --screenEmulation.mobile=false

Result:

Invalid value: 'screenEmulation.mobile' must be a boolean

Specify --help for available options

I expected it to work.

I read the docs of upgrading to version 7 but I can't figure out how to set the value correctly.

I also tried running without setting mobile = false:

lighthouse https://www.google.com --chrome-flags="--no-sandbox --headless" --output=json --output-path=stdout --disable-dev-shm-usage --form-factor=desktop --throttling.throughputKbps=1000 --throttling.rttMs=0 --throttling.cpuSlowdownMultiplier=1 --throttling.requestLatencyMs=0 --throttling.downloadThroughputKbps=0 --throttling.uploadThroughputKbps=0 --screenEmulation.width=1350 --screenEmulation.height=940 --screenEmulation.deviceScaleFactor=1                               
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  ChromeLauncher Waiting for browser. +0ms
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  ChromeLauncher Waiting for browser..... +520ms
  ChromeLauncher Waiting for browser....... +503ms
  ChromeLauncher Waiting for browser.......✓ +3ms
  ChromeLauncher Killing Chrome instance 32 +6ms
Runtime error encountered: Screen emulation mobile setting (true) does not match formFactor setting (desktop). See https://github.com/GoogleChrome/lighthouse/blob/master/docs/emulation.md
Error: Screen emulation mobile setting (true) does not match formFactor setting (desktop). See https://github.com/GoogleChrome/lighthouse/blob/master/docs/emulation.md
    at assertValidSettings (/usr/lib/node_modules/lighthouse/lighthouse-core/config/config-helpers.js:110:13)
    at resolveSettings (/usr/lib/node_modules/lighthouse/lighthouse-core/config/config-helpers.js:327:3)
    at new Config (/usr/lib/node_modules/lighthouse/lighthouse-core/config/config.js:253:22)
    at generateConfig (/usr/lib/node_modules/lighthouse/lighthouse-core/index.js:64:10)
    at lighthouse (/usr/lib/node_modules/lighthouse/lighthouse-core/index.js:43:18)
    at runLighthouse (/usr/lib/node_modules/lighthouse/lighthouse-cli/run.js:224:32)
    at processTicksAndRejections (internal/process/task_queues.js:97:5)

Environment Information

• Affected Channels: CLI
• Lighthouse version: 7.2.0
• Operating System: Linux running inside docker

[adamraine]

This appears to be a bug. Setting screenEmulation.mobile=false passes false as a string not a boolean, but it also doesn't work as a boolean flag.

[samos123]

Thanks @adamraine for confirming it's a bug and not my doc reading skills :)

Just for context, this is blocking me from adopting at lighthouse 7.2.0 at https://github.com/websu-io/websu because I was using --emulated-form-factor=desktop previously and seems there is no way to express that through CLI right now? or is there a workaround I can use?

Reference: https://github.com/websu-io/websu/blob/799e10551e12d395760dae558e9c0b5955831b5d/pkg/api/app.go#L236

[adamraine]

If you just need to test the desktop page, you can use --preset=desktop.

If you need to mess with the exact emulation settings, I would suggest using a custom config like this with --config-path=/path/to/config.js.

[samos123]

I assumed I can't use preset because I manually override the throttling settings and looks like preset would cause conflict with throttling settings? The config-path might be a good workaround for now. Thank you!

[brendankenny]

--no-screenEmulation.mobile can also serve as a workaround for now.

[samos123]

That's more than a workaround! That could be the permanent solution. Thank you @brendankenny it's working well with --no-screenEmulation.mobile