cypress run does not log stderr from plugins

[flotwig]

Current behavior:

Run this existing spec that has a plugin which logs to process.stderr:

npm run cypress:run -- --project ./packages/server/test/support/fixtures/projects/system-node
npm run cypress:open -- --project ./packages/server/test/support/fixtures/projects/system-node

cypress/packages/server/test/support/fixtures/projects/system-node/cypress/plugins/index.js

Lines 1 to 5 in 99ec5c7

	module.exports = (onFn, config) => {
	process.stderr.write('Plugin Loaded\n')
	process.stderr.write(`Plugin Node version: ${process.versions.node}\n`)
	process.stderr.write(`Plugin Electron version: ${process.versions.electron}\n`)
	}

It will log in cypress open, but not cypress run.

Desired behavior:

The pluginsfile should log either way.

[flotwig]

The culprit is that this code path will cause the onStderrData callback to always return falsey:

cypress/cli/lib/exec/spawn.js

Lines 238 to 256 in 99ec5c7

	if (linuxWithDisplayEnv) {
	_.extend(overrides, {
	electronLogging: true,
	onStderrData (str) {
	// if we receive a broken pipe anywhere
	// then we know that's why cypress exited early
	if (util.isBrokenGtkDisplay(str)) {
	brokenGtkDisplay = true
	}
	// we should attempt to always slurp up
	// the stderr logs unless we've explicitly
	// enabled the electron debug logging
	if (!debugElectron.enabled) {
	return false
	}
	},
	})
	}

I believe this was a mistake, as line 252 returns false, but there is no "default case" that returns true after that.

If you add "return true", once again, output will contain Electron debug information (#4255). But we can just filter that out or not set ELECTRON_ENABLE_LOGGING at any point.

[santoshyadavdev]

HI @jennifer-shehane ,
I would like to take this issue.

[flotwig]

@santoshyadav198613 Feel free to pick this issue up, ping me if you have any questions. I think changing that onStderrData callback to return true will be a good starting point.

[santoshyadavdev]

Hi @flotwig ,
Are we looking for this to be logged?

[santoshyadavdev]

Hi @flotwig ,
PR is open now.

[flotwig]

Hi @flotwig ,
Are we looking for this to be logged?

Yep, that's great!

[santoshyadavdev]

Hi @flotwig,
Cool just need some help on Testing , mentioned the error which I am getting in PR.

[justin335]

Nice

[purejgleason]

Also seems to not log std err in tests

[jennifer-shehane]

This now works. I'm not sure which version this was released in. Closing as resolved.

@purejgleason console.logs or stderr within a test file is exectued within the browser - so will not log to stdout. Use cy.task to log any info within a test to stdout as shown here: https://on.cypress.io/api/commands/task#Usage