`haul init` clobbers existing project.ext.react gradle config

Current Behavior

haul init adds the following block to my project’s android/app/build.gradle above the react.gradle import, which overwrites my existing project.ext.react assignment.

project.ext.react = [
    cliPath: "node_modules/haul/bin/cli.js"
]

Expected Behavior

haul init should merge the new cliPath property into project.ext.react config if it exists, or fall back to the current behavior and create a new project.ext.react block.

Haul Configuration (webpack.haul.js)

module.exports = () => ({
  entry: `./index.js`,
});

Your Environment

software	version
Haul	1.0.0-beta.13
react-native	0.53.0
node	v9.3.0
npm or yarn	v1.3.2

Workaround is just to manually merge the two project.ext.react blocks, but it’d be nice if haul init did this for you.

It looks like it just needs a bit more logic where it adds this block here

I’m happy to PR a fix in the coming week : )

[thymikee]

If that helps the case, but we can also search for existing project.ext.react and bailout with a proper warning to the user

[FLGMwt]

I think we can get away with not doing anything clever string-wise (especially since we’d have to deal with comments and multiple possible locations where project.ext.react is manipulated). Since we’re doing the replacing right about the react.gradle import and I think we can be reasonably sure this is the furthest down in the config that the user would assign their own ext.react values, how about just swapping out the snippet with a graceful initialization of ext.react and then a more surgical cliPath assignment? We’d end up with giving the user the following:

if (!project.hasProperty('react')) {
    project.ext.react = [:]
}
project.ext.react['cliPath'] = "node_modules/haul/bin/cli.js"

apply from: "../../node_modules/react-native/react.gradle"