moved errorCount to beginning to account for errors in all themes, no…

[bka]

For deployment, we need bin/magento to exit with a return code != 0 to indicate if something went wrong.

As far as I am aware this issue is at least related to following other issues:

• setup:static-content:deploy, setup:di:compile and deploy:mode:set will not return a non-zero exit code if any error occurs #3060
• bin/magento must return non zero on exceptions #3189

The above pull request already addresses the issue that \Magento\Framework\Console\Cli::RETURN_FAILURE will be used if $this->errorCount > 0.
However, the current develop branch sets $this->errorCount = 0; for every iteration, which clears errors from previous themes.
I would suggest moving the errorCount to the beginning of deploy function, to account for all errors in all steps, because otherwise it gets reset everytime and only the last step in the loop will count.

Preconditions

1. Tested on Magento 2.1.0 latest dev version on 903dcbb

Steps to reproduce

1. Produce a syntax error in less, e.g. by creating an empty less: mkdir -p app/design/frontend/Magento/luma/Magento_Email/web/css/ && touch app/design/frontend/Magento/luma/Magento_Email/web/css/email.less
2. Run bin/magento setup:static-content:deploy
3. See error in output: e.g. Successful: 2138 files; errors: 1

Expected result

1. Status code echo $? should be !=0 after running task

Actual result

1. Status code echo $? is 0

[magento-cicd2]

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[bka]

Sorry, closed in favour of having a separate branch for it, recreated here: #6349