I can't install because of missing org.apache.commons.lang lib. Where can i get this?

See this github issue for an answer.

How do i know a PHP project is symfony-aware?

Your project icon in the PHP package explorer will have a small Symfony logo attached to it. Also, if you open the properties of your project and see the Builders section, you should see a Symfony builder.

Service XYZ is not being completed at all, but others are. How come?

The plugin cannot infer types of synthetic services - services which are dynamically injected during runtime. For those cases, there's a preference page called Services where the id/class mapping can be stored. After that, the plugin should complete the service properly.

There's no additional codeassistance showing up, what can i do?

The plugin indexes services and annotation during the build process. Try to clean the project (project -> clean). If it's still not working, check if the project has a Symfony nature.

Still no code assist, what now?

Check your build-path - project -> properties -> PHP build path - and ensure that all your source folders are in the build path. Also make sure that none of your sourcefolders are excluded.

When reporting an issue, how can get stacktraces to ease debugging?

Eclipse can be started with various debugging options. This can be turned on/off for each installed plugin independently. To debug the symfony plugin, create a file called .options in your Eclipse installation folder. The file should contain the following lines:

Then restart eclipse from the commandline with these flags: eclipse -debug .options

Try to reproduce the problem and monitor the commandline - please provide these stacktraces in your github issues.

How do i know which version of the plugin is installed?

Eclipse(Mac) / Help(Windows/Linux) -> About Eclipse -> SDK -> Installation Details -> Plugins lists all installed plugins and their version. Note that the Symfony eclipse Feature actually consists of multiple plugins listed on that page.