Regression: heroku run -x no longer returns correct exit code

[dzuelke]

Since 8.2.0:

$ heroku --version
heroku/8.1.9 darwin-x64 node-v16.19.0

$ heroku run -x -- 'bash -c "exit 2"' || echo $?  
Running bash -c "exit 2" on ⬢ sushi... up, run.6915 (Standard-1X)

 ›   Error: Process exited with code 2
 ›   Code: 2
2

$ heroku update --version 8.2.0
…

$ heroku --version             
heroku/8.2.0 darwin-x64 node-v16.19.0

$ heroku run -x -- 'bash -c "exit 2"' || echo $?
Running bash -c "exit 2" on ⬢ sushi... up, run.7202

Error: Process exited with code 2
1

$ heroku update
…

$ heroku --version
heroku/8.4.2 darwin-x64 node-v16.19.0

$ heroku run -x -- 'bash -c "exit 2"' || echo $?
Running bash -c "exit 2" on ⬢ sushi... up, run.2600 (Standard-1X)

Error: Process exited with code 2
1

Note: you have to use bash -c "exit 2" as the command; simply using exit 2 will terminate the shell and then the internal echo of the status code for later reading will not execute:

cli/packages/run-v5/lib/dyno.js

Line 54 in b451c6b

let command = this.opts['exit-code'] ? `${this.opts.command}; echo "\uFFFF heroku-command-exit-status: $?"` : this.opts.command

(the effective command is exit 2; echo "\uFFFF heroku-command-exit-status: $? vs bash -c "exit 2"; echo "\uFFFF heroku-command-exit-status: $?).

[k80bowman]

Thank you for all of the details on this, we are looking into it. In the meantime, for you or anyone else who runs into this issue, the workaround for now is to downgrade to version 8.1.9 using heroku update --version=8.1.9. We'll update this issue when we release a fix.

[dzuelke]

So, just an explanation of how this even works internally... when -x is passed to heroku run, the given command is suffixed with a special echo that returns $?, the exit status of the program:

cli/packages/run-v5/lib/dyno.js

Line 54 in b451c6b

let command = this.opts['exit-code'] ? `${this.opts.command}; echo "\uFFFF heroku-command-exit-status: $?"` : this.opts.command

This \uFFFF heroku-command-exit-status: … output is later detected and used:

cli/packages/run-v5/lib/dyno.js

Lines 315 to 328 in b451c6b

	let exitCode = data.match(/\uFFFF heroku-command-exit-status: (\d+)/m)
	if (exitCode) {
	debug('got exit code: %d', exitCode[1])
	this.push(data.replace(/^\uFFFF heroku-command-exit-status: \d+$\n?/m, ''))
	let code = Number.parseInt(exitCode[1])
	if (code === 0) this.resolve()
	else {
	let err = new Error(`Process exited with code ${cli.color.red(code)}`)
	err.exitCode = code
	this.reject(err)
	}
	return
	}

[dzuelke]

Related: #2468

[dzuelke]

Confirmed fixed by #2467.