
Summary of my Summer of Code 2019

This post is a summary of my Summer of Code 2019.
My project was to bring Dart development support to the Eclipse IDE.
To do so I created a plugin that consumes the Dart analysis server using [LSP4E](https://projects.eclipse.org/projects/technology.lsp4e).
It also provides syntax highlighting using [TM4E](https://projects.eclipse.org/projects/technology.tm4e) and many more features listed below.

## Features

_The following list showcases the most significant features of the plugin I (and other contributors) added during GSoC 2019._

-   **Running Dart programs directly from Eclipse** - [eclipse/dartboard#1](https://github.com/eclipse/dartboard/issues/1)

    -   Standard & error output in a dedicated console
    -   Support for multiple Launch configurations
    -   Running single files from the context menu

-   **Dart preference page** - [eclipse/dartboard#10](https://github.com/eclipse/dartboard/issues/10)

    -   Set the location for the Dart SDK that should be used for all actions
    -   Choose whether to automatically synchronize the dependencies of project

-   **First class Pub support** - [eclipse/dartboard#107](https://github.com/eclipse/dartboard/pull/107)

    -   Automatic synchronization of Pub dependencies when changing the `pubspec.yaml` file
    -   Shortcut for running `$ pub get` manually

-   **Creating new Dart projects and files** - [eclipse/dartboard#115](https://github.com/eclipse/dartboard/pull/115)

    -   Stagehand templates are also supported

-   **Usage of the Dart logo** - [eclipse/dartboard@a23fc1f](https://github.com/eclipse/dartboard/commit/a23fc1f57cd3fdc6e702759c507aa977f7dd7561)

-   **Import existing Dart projects directly into the workspace** (+ automatic dependency synchronization) - [eclipse/dartboard#116](https://github.com/eclipse/dartboard/pull/116)

## Upstream Bug Fixes

During development I encountered many issues with the libraries and tools I was using.
As I was already aware I took the time to fix them directly and provide a patch or PR for the corresponding library.

-   A `NullPointerException` in LSP4E's `SymbolsModel#getChildren`

    -   Issue: [eclipse/dartboard#4](https://github.com/eclipse/dartboard/issues/4)
    -   Fix: [Change 139273](https://git.eclipse.org/r/#/c/139273/)

-   Adjusted the Eclipse Light syntax theme in TM4E to match the classic Eclipse theme better

    -   Issue: [eclipse/dartboard#21](https://github.com/eclipse/dartboard/issues/21)
    -   Fix: [eclipse/tm4e#215](https://github.com/eclipse/tm4e/pull/215)

-   Using the quick access menu in Eclipse resulted in an Exception.
    This was caused by LSP4E not adhering to the LSP spec. - Issue: [Bug 548155](https://bugs.eclipse.org/bugs/show_bug.cgi?id=548155) - Fix: [Change 143723](https://git.eclipse.org/r/#/c/143723/)

-   The `textDocument/didSave` notification is not supported by the Dart analysis server but LSP4E sent it anyway and this resulted in an error

    -   Issue: [eclipse/dartboard#32](https://github.com/eclipse/dartboard/issues/32)
    -   Fix: [Change 143922](https://git.eclipse.org/r/#/c/143922/)

-   Another NPE in TM4E's `ThemeContribution`
    -   Issue: [eclipse/tm4e#207](https://github.com/eclipse/tm4e/issues/207)
    -   Fix: [eclipse/tm4e#217](https://github.com/eclipse/tm4e/pull/217)

## Things Left to do

I have completed all of my goals I set in the initial proposal for GSoC.
However a few things and features have come up during development that I plan on taking care of in the near future.

-   **Flutter support** - Flutter apps need to be run using the special `$ flutter` command suite, instead of the default SDK
    -   [eclipse/dartboard#109](https://github.com/eclipse/dartboard/issues/109)

Other things that could be enhanced include:

-   **Pub console** - Currently there is now way to see the output of the pub commands
    -   [eclipse/dartboard#117](https://github.com/eclipse/dartboard/issues/117)
-   **Webdev support** - Dart apps that should be run on the browser need to be run using the `$ webdev` command line tools
    -   [eclipse/dartboard#110](https://github.com/eclipse/dartboard/issues/110)

I hope to be able to work on them but community contributions are always welcome.

A full list of commits and issues can be found on the [project's GitHub repository](https://github.com/eclipse/dartboard).
Installation instructions can also be found there.

## Appreciation

In the early days, Lakshminarayana Nekkanti has joined the project as a committer.
He has been extremely helpful since by fixing bugs in the Eclipse platform that have been open for years ([Bug 513034](https://bugs.eclipse.org/bugs/show_bug.cgi?id=513034)) and contributing a lot of features and knowledge to the plugin.
Thank you, Lakshminarayana!

I would also like to thank Lars Vogel who has been my Mentor and helped tremendously when I was unsure what to do.


GSoC 2019 Summary: Dart support for the Eclipse IDE

Automatic [pub.dev](https://pub.dev/) dependency synchronization, [stagehand templates](https://pub.dev/packages/stagehand) and theme improvements for TM4E.



## Pub dependency synchronization

[pub.dev](https://pub.dev/) is the main source of packages for Dart projects.
Dependencies are added to a `pubspec.yaml` file and the `$ pub get` command is used to download the packages from the registry.
Since most projects require at least a few dependencies this step _must_ be taken before the project compiles without errors.

To ease this process a little, the command is now automatically run when saving the `pubspec.yaml` file in Eclipse.
With this, required dependencies are automatically downloaded when a project is imported or when a new package is added to the `pubspec.yaml` file.

If you don't want this behavior the feature can be disabled from the preference page.
Manually running the synchronization is also supported from the context menu of a project.

![Pub context handler](/assets/img/pub-command.png)

The current progress of the synchronization is reported to the _Progress_ view.

![Pub progress](/assets/img/pub-dependencies.gif)

## Stagehand

[Stagehand](https://pub.dev/packages/stagehand) is a CLI tool, written in Dart, that generates new projects from a list of templates.
There are different project types to chose from, like Flutter, AngularDart or just console applications.
After a template is generated the project contains a `pubspec.yaml` file containing all necessary dependency information and various entry files that are required by the type of project.

This tool is now supported graphically by the _New Dart Project_ wizard also provided by Dartboard.
Under the hood the plugin uses the exact executable from `pub.dev`.
And by automatically updating it we make sure that new templates can be immediately used.

This is how the _New Dart Project_ wizard looks now:
![Stagehand](/assets/img/stagehand.png)

At first selection of the Wizard (after a fresh IDE start) _Stagehand_ is updated and its templates are fetched.
After that job is finished the available templates are added to the combo box.
If no template should be used the _Use Stagehand template_ checkbox can be unchecked and an empty project is generated.

Subsequent usages of the wizard use cached versions of the templates list to not strain your network or the [pub.dev](https://pub.dev/) registry too much.

## Project import

Not every Dart project was created from Eclipse though.
So to be able to use Dartboard with existing Dart projects it is required to import them into the workspace.
For this task we now provide a shortcut to import Dart projects from the _Import Project_ context menu entry.

Currently it simply opens the _Projects from Folder or Archive_ wizard.
This wizard however allows to specify a `ProjectConfigurator` that takes care of selecting folders that should be imported as a project.
In our own configurator we traverse all children and look for `pubspec.yaml` files.
Every folder that contains such a file is considered to be a separate project.

## Eclipse light theme for TM4E

TM4E can be used to apply different syntax highlighting to the editor.
We provide a configuration file that specifies how certain words inside the editor should look.
It also gives the option to select what theme to use.
There are different light and dark themes available, like _Solarized Light_ or the classic Eclipse Java editor theme.

I provided a patch to add some missing styles to the latter to make it look more like the classic theme.
This is what it looks like now:
![Eclipse light theme](/assets/img/eclipse-light-new.png)

See [eclipse/tm4e#215](https://github.com/eclipse/tm4e/pull/215).

## Wrap up

With two weeks to go until the end of Summer of Code 2019 there is not that much left to do for me to fulfill my proposed timeline.
One major thing that is still missing are automated tests.
I have started work on it now and will work on that for the last two weeks.

This will also be my last update post on Summer of Code as the next post will be a summary of my whole summer.

Dartboard: Pub support, Stagehand templates & better theming


Dart icon, bug fixes and a new committer. Dartboard is getting better and better every week. So what's new?

## Eclipse Marketplace

Installing the plug-in typically involved adding an update site, downloading its content and then installing the plug-in.
This process is quite tedious.
That's why I added the plug-in to the [Eclipse Marketplace](https://marketplace.eclipse.org/content/dartboard), which is much nicer to use.

To install the plug-in from the marketplace make sure you have the [Marketplace client](https://www.eclipse.org/mpc/) installed.
Open the [marketplace entry](https://marketplace.eclipse.org/content/dartboard) and drag and drop the install button into your running Eclipse instance.
Alternatively, you can open the Marketplace client from the **Help>Eclipse Marketplace...** menu and search for **Dartboard**.

In the future you will also receive notifications about updates and an option to update the plug-in.

## Dart Icon

Since using the icon of the Dart language requires to first ask permission from Google, it took some time to use the logo in the project.
Now however we are allowed to use the icon and I have added it to the code base.
It is now shown in many places like launch configurations or file creation wizards.

![Dart logo on New Project Shortcut](/assets/img/new-project-shortcut.png)

## Property Testers Instead of Project Natures

In my last post I wrote about the usage of project natures in the plug-in.
After reevaluating this, we came to the conclusion that it is better to use property testers instead.
The reason for this is, that project natures are written into the project configuration file.
One drawback to this is that a project nature is extremely Eclipse specific.
This means that just importing a project might not enable all features.

To curb with this problem, I removed the project natures again and added a `PropertyTester` that checks for the existence of a `pubspec.yaml` file or any file with the `.dart` file extension.

## Dart Console

The first implementation of the Dart console, that was used to display output from Dart programs, was very basic.
It did not allow to cancel the currently running program and did not remove itself when it wasn't needed anymore.

It turns out that the Eclipse IDE APIs actually allow to use a `ProcessConsole` for these tasks.
Using the Console just requires to add a process.
It will take care of life cycling and lets the user cancel longer running tasks.

## Preference Page

The Dart preference was also heavily improved.
Firstly, on first starts of the IDE with the plug-in installed it automatically tries to detect the location of the Dart SDK that is on the path of the host system.
If it can't find an SDK, a warning will be shown.

Secondly, the validations on the preference page now validate if the entered location is actually a valid Dart SDK location.
If not the "Apply" button will not be enabled.

![Preference Page Validation](/assets/img/preference-validation-after.gif)

## Custom Methods in LSP4J

The Dart analysis server uses some custom methods when communicating with the client.
To handle these however a custom handler for each method is needed.
If no handler is available LSP4J will throw an error.

The custom method from the Dart analysis server was `$/analyzerStatus`.
The `$` at the beginning indicates that it's a custom method.
The `analyzerStatus` method is used to notify the client of the current analyzer status (e.g. if the server is currently analyzing or not).
This information could be used to indicate the status in the UI in the future.
For now it was sufficient to just have a handler that essentially suppressed the error message.

See [dartboard#35](https://github.com/eclipse/dartboard/issues/35) for more details.

## New Committer

I would also like to mention that the project now has its first committer: Lakshminarayana Nekkanti.
After he raised a few pull request in the past weeks, we decided that it would be very nice to have him as a committer.

Thanks Lakshminarayana for your excellent work and code reviews.

## Licenses and Signing

Artifacts from our build server are now signed by the Eclipse Foundation.
Essentially this means you can be sure that the artifact you are downloading is in fact our plug-in.
Upon installation the licenses (EPL2) are now also shown.

## Conclusion

As this post marks half of my time with Google Summer of Code, there is only one and a half month to go.
There are still some things left to do and I'm looking forward to increasing the plug-ins user count and its features in the next weeks.

_Dart and the related logo are trademarks of Google LLC. We are not endorsed by or affiliated with Google LLC._


Hey There! I am Jonas!

I enjoy working with the web, am not afraid of new things and share stuff I figure out while learning.

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