Fix the parse error when specifying an unknown version.

Summary:
**Motivation**

When running `react-native-git-upgrade` with an unknown version, the error message isn't very helpful

**Test Plan**

- Publish the `master` branch to Sinopia
- Run `react-native-git-upgrade 0.666.0` inside a RN project
- Error message is `SyntaxError: Unexpected end of JSON input`
- Publish this branch to Sinopia
- Run `react-native-git-upgrade 0.666.0` inside a RN project
- Error message should be `Error: The specified version of React Native 0.666.0 doesn't exist.
Re-run the react-native-git-upgrade command with an existing version,
for example: "react-native-git-upgrade 0.38.0",
or without arguments to upgrade to the latest: "react-native-git-upgrade".`
Closes #11264

Differential Revision: D4265553

Pulled By: mkonicek

fbshipit-source-id: 8597eb09cc3397bfa6d2205a9b3bb30acfad530f

react-native-git-upgrade/checks.js

@@ -54,21 +54,9 @@ function checkGitAvailable() {
  }
}

function checkNewVersionValid(newVersion, requestedVersion) {
  if (!semver.valid(newVersion) && requestedVersion) {
    throw new Error(
      'The specified version of React Native ' + requestedVersion + ' doesn\'t exist.\n' +
      'Re-run the react-native-git-upgrade command with an existing version,\n' +
      'for example: "react-native-git-upgrade 0.38.0",\n' +
      'or without arguments to upgrade to the latest: "react-native-git-upgrade".'
    );
  }
}

module.exports = {
  checkDeclaredVersion,
  checkMatchingVersions,
  checkReactPeerDependency,
  checkGitAvailable,
  checkNewVersionValid,
};

react-native-git-upgrade/cliEntry.js

@@ -10,6 +10,7 @@

const fs = require('fs');
const os = require('os');
const assert = require('assert');
const path = require('path');
const shell = require('shelljs');
const Promise = require('promise');
@@ -25,7 +26,6 @@ const {
  checkMatchingVersions,
  checkReactPeerDependency,
  checkGitAvailable,
  checkNewVersionValid
} = require('./checks');

log.heading = 'git-upgrade';
@@ -96,6 +96,25 @@ function readPackageFiles(useYarn) {
  }
}

function parseInformationJsonOutput(jsonOutput, requestedVersion) {
  try {
    const output = JSON.parse(jsonOutput);
    const newVersion = output.version;
    const newReactVersionRange = output['peerDependencies.react'];

    assert(semver.valid(newVersion));

    return {newVersion, newReactVersionRange}
  } catch (err) {
    throw new Error(
      'The specified version of React Native ' + requestedVersion + ' doesn\'t exist.\n' +
      'Re-run the react-native-git-upgrade command with an existing version,\n' +
      'for example: "react-native-git-upgrade 0.38.0",\n' +
      'or without arguments to upgrade to the latest: "react-native-git-upgrade".'
    );
  }
}


function setupWorkingDir(tmpDir) {
  return new Promise((resolve, reject) => {
@@ -240,15 +259,11 @@ async function run(requestedVersion, cliArgs) {

    log.info('Get information from NPM registry');
    const viewCommand = 'npm view react-native@' + (requestedVersion || 'latest') + ' peerDependencies.react version --json';
    const viewOutput = await exec(viewCommand, verbose).then(JSON.parse);
    const newVersion = viewOutput.version;
    const newReactVersionRange = viewOutput['peerDependencies.react'];
    const jsonOutput = await exec(viewCommand, verbose);
    const {newVersion, newReactVersionRange} = parseInformationJsonOutput(jsonOutput, requestedVersion);
    // Print which versions we're upgrading to
    log.info('Upgrading to React Native ' + newVersion + (newReactVersionRange ? ', React ' + newReactVersionRange : ''));

    log.info('Check new version');
    checkNewVersionValid(newVersion, requestedVersion);

    log.info('Setup temporary working directory');
    await setupWorkingDir(tmpDir);