Difference between revisions of "JSDT/Development"

Revision as of 04:20, 5 October 2015

As of WTP 3.0, JSDT is part of the Web Tools Platform.

Contributing to JSDT

The JSDT is driven by a very small development group with limited resources. ANY serious developers or contributors will be enthusiastically welcomed. For more information on how to become a Committer, check the standard Eclipse process (see New Committer Election). For more information about contributing to JSDT in general, or for questions about its internals, contact wtp-dev.

JSDT Functional Testing

Testing Scenarios

Reporting Bugs

Report bugs through Eclipse Bugzilla under WebTools catagory, JSDT component.

Here is a list of open JSDT bugs. We're working through them as fast as we can!

You can receive notifications of incoming bugs by monitoring account jsdt.javascript-inbox@eclipse.org in https://bugs.eclipse.org/bugs/userprefs.cgi?tab=email

JSDT Sources

Git Repository: webtools.jsdt.git

Detailed repository contents you can find at this page: http://wiki.eclipse.org/WTP_Git_Migration_Checklist

These plug-ins have no dependencies other than the Eclipse base (nor do they depend on anything else in WTP). Using these plug-ins, a standalone JavaScript Project can be created and used:

• bundles/org.eclipse.wst.jsdt.core
• org.eclipse.wst.jsdt.manipulation
• org.eclipse.wst.jsdt.ui

The Feature project for these is:

• features/org.eclipse.wst.jsdt.feature

Building and testing JSDT locally

Simply run mvn clean verify -Pbuild-individual-bundles -DskipTests=false. This command will run the Unit-tests. After the build, you can install your JSDT snapshot in an Eclipse IDE or other RCP application using the p2 repository in location site/target/repository

Gerrit Reviews

Pushing a new patch for review

You can use Gerrit (mandatory reading, important to set up hooks, SSH keys, CLA & other) to push Git commits on JSDT repositories. The repo URL for JSDT@Gerrit is ssh://user@git.eclipse.org:29418/jsdt/webtools.jsdt. Once logged into Gerrit, you can see more details about the URL at https://git.eclipse.org/r/#/admin/projects/jsdt/webtools.jsdt .

Assuming you named this repo gerrit, you can push a commit to one of this repository with

$ git push gerrit HEAD:refs/for/master

This will give you the URL of the Gerrit review where you can interact with project committers to get your commit merged.

In case you need to push another version of the patch, don't forget to copy the Change-Id from the Gerrit review if you didn't set up the git hook. Providing another version of the patch doesn't require a new commit, simply amend the one you already pushed, and push it again:

$ git log -1 #Shows the commit. Message should contain Sign-Off-By and Change-Id
$ git add file/to/change
$ git commit --amend # add --signoff if Sign-Off-By is missing, and copy Change-Id from Gerrit review if missing
$ git push gerrit HEAD:refs/for/master # will create another version of the patch, on the same review.

Reviewing a patch

Incoming patch automatically triggers a build and will receive an automated vote according to whether patch breaks the build/tests or not. The CI job providing this vote is https://hudson.eclipse.org/webtools/job/jsdt-gerrit.

• Anytime Hudson votes with -1, it generally means that something is wrong with the patch: it breaks build or make a test failing, so the patch shouldn't be merged. The build log should be inspected by submitter and reviewers to understand the cause of the bug and submit (or assist in submitting) a better patch.
• Hudson voting +1 means that the test didn't introduce any regression visible by build or automated tests.

Anyone is free to add comments and vote on a review. Committers have the final power to decide whether or not a patch can be merged.

List reviews and be notified

You can see the list of open Gerrit reviews at https://git.eclipse.org/r/#/q/status:open+project:jsdt/webtools.jsdt,n,z .

Regular contributors and committers should really subscribe to notifications of proposed patches. You can set up notifications for proposed incoming changes at https://git.eclipse.org/r/#/settings/projects

Static analysis with SonarQube

JSDT uses SonarQube to get reports about static analysis. Those can show potential bugs, performance traps, or just bad practices. Here is the status of JSDT on these topics: https://dev.eclipse.org/sonar/dashboard/index/org.eclipse.webtools.jsdt:jsdt-parent . Any help to clean up warnings is welcome!

Architecture

HTML an JSP editors

JSDT provides JavaScript support for the WTP HTML and JSP editors in the WTP Source Editing project Git repositories. GitHub

The following plug-in projects provide JSDT integration with WTP's HTML and JSP editors:

• webtools.sourceediting.git/bundles/org.eclipse.wst.jsdt.web.core
• webtools.sourceediting.git/bundles/plugins/org.eclipse.wst.jsdt.web.ui
• webtools.sourceediting.git/bundles/plugins/org.eclipse.wst.jsdt.web.support.jsp - contains JSP-specific functionality
• webtools.sourceediting.git/bundles/plugins/org.eclipse.wst.jsdt.support.firefox - contains bindings for Mozilla FireFox, current as of FF 2.0.x (deprecated)
• webtools.sourceediting.git/bundles/plugins/org.eclipse.wst.jsdt.support.ie - contains bindings for Microsoft Internet explorer (deprecated)

JSDT tests

The following are the JUnits test plug-ins for JSDT:

• tests/org.eclipse.wst.jsdt.core.tests.compiler - (test suite is org.eclipse.wst.jsdt.core.tests.compiler.JSDTTestAll)
• tests/org.eclipse.wst.jsdt.core.tests.model - (test suite is org.eclipse.wst.jsdt.core.tests.model.AllJavaModelTests)

These test plug-ins are new to WTP 3.1 and above:

• webtools.sourceediting.tests.git/tests/org.eclipse.wst.jsdt.web.core.tests - (test suite is org.eclipse.wst.jsdt.web.core.tests.translation.AllWebCoreTests)
• webtools.sourceediting.tests.git/tests/org.eclipse.wst.jsdt.web.ui.tests - (test suite is org.eclipse.wst.jsdt.web.ui.tests.AllWebUITests)

These test plug-ins are new to WTP 3.2 and above:

• webtools.jsdt.tests.git/tests/org.eclipse.wst.jsdt.ui.tests - (test suite is org.eclipse.wst.jsdt.ui.tests.JSDTUITests)

JSDT packages

JSDT Core

The JSDT core plugin (org.eclipse.wst.jsdt.core) provides the core JavaScript modeling.

JSDT UI

User interface code

Generating the parser

Follow the instructions at http://www.eclipse.org/jdt/core/howto/generate%20parser/generateParser.html for generating the parser. The parser grammer file is located in cvs at sourceediting/plugins/org.eclipse.wst.jsdt.core/grammer/js.g

Design

The JavaScript Development Tools design would use the JDT design with the necessary adjustments made for JavaScript.

As far as the JavaScript Development Tools design is concerned, the major differences between Java and JavaScript are:

• Javascript has no explicit typing support, whereas in Java everything is typed, and incorporates argument types in function signatures.
• At the top level, a JavaScript file can contain any program statement, whereas a Java file only contains a Class.
• JavaScript has no classpath/jar file concept

Other areas where the java/JavaScript differences will necessitate changes:

• syntax differences - parse definitions
• additional program elements with no correspondence in Java
  • object literals
  • for (var in collection)

Inferred Types

In order for some JDT-based functionality (such as code completion) to work correctly, class type information needs to be available. This information is not available in JavaScript, but it can be inferred in many cases. A type inferring framework has been put in place to support this functionality, examining the JavaScript Abstract Syntax Tree (AST) and generating "virtual" class information. Type inferring is extensible, so the unique conventions among various JavaScript Toolkits (e.g. Dojo, jQuery, Prototype, etc.) can be handled, although through WTP 3.1 it has remained provisional. Inferred types may participate in refactoring, but their visibility within the UI is still being discussed.

JavaScript file handling

Java files have a very top down structure, where files only contain classes, which only contain fields, methods, and inner classes, and program statements only contained within methods. Because of this, some JDT functionality will not work for JavaScript, because a program statement can be directly at the top of a JavaScript file. The relevant JDT code is still undergoing refactorings to support these scenarios.

Variable/function resolution

In Java, everything is resolvable because of the classpath, package structure, and import statements. This has no correspondence in JavaScript, where functions themselves may also be resolvable as types.

Libraries

The JSDT mimics the JDT Java Build Path and classpath container mechanisms to offer JavaScript library support. JSDT libraries are collections of JavaScript source files that have prototyped object/class definitions and JSDoc. The inference engine then models these libraries and places each object/field/function in the projects Global Scope, making them available to every JavaScript file in the project. Because the library contents are not directly executed by JSDT, it isn't necessary for them to contain the complete implementation of those objects. In fact, the standard JavaScript runtime is itself presented as a source file containing stubs for the specification's contents. Bindings for nonstandard and future runtimes are similarly easy to create and use.

To illustrate-- the JSDT contains a FireFox library plugin with about 150k of JavaScript and JsDoc. This library represents the class structure within the FireFox browser that is accessible to a web page's JavaScript, but does not contain any implementation to the functions it declares. If a user wishes to target their JavaScript source to FireFox specifically, they would add the FireFox library to their project and gain content completion and hover help for the FireFox objects. Users may also limit the objects/functions/fields visible in the project by adding or removing libraries.

Libraries aren't limited to browser objects. AJAX runtimes can fit nicely into libraries, as would a website's standard set of utility functions. Really the possibilities are limitless. And the library mechanism is extremely easy to expand both by the end-user or through extension points.

Functionality mapping

This table shows how the JDT functionality corresponds to the JavaScript functionality. It does not include anything where there is a direct one to one correspondence.

Extension Points

The JSDT functionality is embeddable. This means, for instance, that the JavaScript editing capabilities is embeddable within HTML and JSP Editors, both within script tags, and script attribute values. The JSDT is flexible so script support in other languages is possible using translator interfaces being planned for WTP 3.1.

The following JSDT extension points are supported :

• Global Scope variable initializer
• Global Scope container initializer core
• Code formatter
• Validation participant

 Currently the JSDT is represented in an AST.

The following jsdt.ui extension points will be supported :

• Global Scope container initializer ui (Wizzard, content assist images and type/text naming)
• javascript element filter
• javaScriptEditorTextHovers
• jsdocCompletionProcessor
• quickFixProcessors
• quickAssistProcessors
• foldingStructureProviders
• queryParticipants
• javaScriptCompletionProposalComputer
• javaScriptCompletionProposalSorters