SS4 compatibility tracker - Subsites 2.0

[robbieaverill]

Issue to track progress for upgrading to SilverStripe 4 compatibility.

Requirements

• add SilverStripe\Subsites and SilverStripe\Subsites\Tests namespaces SilverStripe 4 Compatibility #289
• implement core module namespaces SilverStripe 4 Compatibility #289
• upgrade changes in API SilverStripe 4 Compatibility #289
• add $table_name to DataObjects SilverStripe 4 Compatibility #289
• run PHPCS linter Update Travis configuration for PHP 5.6-7.1, add composer dependencies and codecov.io config #291
• update CI tool configurations (Travis, Scrutinizer, Codecov.io) Update Travis configuration for PHP 5.6-7.1, add composer dependencies and codecov.io config #291
• fix Behat tests, uncomment Travis configuration to run them Fix up test suite, re-enable Behat, update further SS4 API changes #294
• move templates into namespaced locations API Move templates to namespaced location, remove unused templates #304
• move translations to namespaced classes NEW Namespace translations, implement into class localisation calls #305 and SS3 translations are frozen. Please contribute translation fixes via pull requests to lang files. #306 (which needs to be merged up)
• review SilverStripe upgrader tool exclusion rules, add as necessary Add upgrade exclusion rules #307
• add $segment to BuildTasks NEW Add segment to SubsiteCopyPageTask #303
• move code/ to src/ Rename "code" to "src" for PSR-4 consistency #301

Bugs

• fix middleware db bootstrapping Bootstrapping issue: InitStateMiddleware needs to catch DatabaseException #295
• Asset admin doesn't work the same way as in SS3, so we'll need to come up with a way of allowing the FileSubsites extension to either filter the file list, visually indicate that a file is not visible in a given subsite at that point, or add a dropdown to the details screen to switch subsite Update FileSubsites extension so it works with asset admin #296
• Page type blacklisting doesn't work Page type blacklisting doesn't have any effect #297
• DB not ready kills application execution FIX Ensure delegated requests are continued when DB builds fail in middleware #302

Ideas/enhancements

• Add silverstripe-webpack module configuration for building styles
• Move to using a middleware for Subsites rather than global state modification and data query hacks?
• Replace old use of ORM with newer equivalents, e.g. manual SQL joins with SQLSelect::leftJoin etc
• "move all the common logic from these *Subsites extensions into a base SubsitesExtension class; FileSubsites would then only contain file-specific overrides to this."

[tractorcow]

Added an issue to fix middleware

[robbieaverill]

Added issues for the asset admin/subsite compatibility, and for the page blacklist not working.

Perhaps once #294 is merged we should log the remaining tasks as separate issues and close this?

[robbieaverill]

The PRs listed above are the last of the smaller fixes for this ticket. Once merged I'll close this and we can work from individual issues.