fix packager start in 0.58

[dulmandakh]

This PR fixes packager during react-native run-ios and react-native run-android.

On reddit and discord many developers say that react-native run-ios failing on 0.58. But I found that react-native start works just fine. So did some investigation and found that if check is false when react-native run-ios but true when react-native start.

react-native/local-cli/cli.js

Line 23 in 57ad197

if (require.main === module) {

It checks if script is run from shell, then starts the packager. Also found that react-native start calls this react-natvie/local-cli/cli.js directly and check is true. And dug little further to find that packager.sh is calling react-native/cli.js which imports react-native/local-cli/cli.js, therefore check is false.

[pull-bot]

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[kelset]

lgtm

[grabbou]

It's interesting this is not present on 0.57, even though there are no changes to the files as far as I am aware.

[cpojer]

I don't really get why this was failing? The top level cli.js is the same as this one :O

[dulmandakh]

local-cli has a check that if it's run from cli or imported as a module, and it'll run it's called from cli. top level cli.js requires it, so the check is failed and not run.

if (require.main === module) {

[cpojer]

Ah, got it. Sorry I didn't realize it was used that way.

[cpojer]

I'd like to find out why we didn't discover this during testing. Since this is basic functionality, we should ensure it never breaks. cc @grabbou