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NOTE: The development team is currently supporting IDEA versions 2016 and later. Support for version 13.1 been removed as of release 0.9.8.*   Support for versions 14 and 15 are stopped as of release 0.11.2.

Reporting errors

Things that will help us fix your bug:

  • A minimal code example. For example if you have some completion issue, you can add the simplest Haxe that can reproduce the issue.

  • We’d like to know your:

    • Plugin version (very important!)
    • IDEA version
    • OS and OS version
    • JDK version
  • Check if the bug already exists at the HaxeFoundation repository. If it does, add your example to the discussion.

Development Environment

You will need the release version of Intellij IDEA Ultimate 2016.1 or later to develop the plugin. There are reports that you can develop with IDEA Community Edition, though extended functionality such as diagrams and hierarchy panels will not be available and you wont be able to test their Haxe equivalents.


Install the following plugins from Intellij IDEA plugin manager.


  • Plugin DevKit
  • UI Designer
  • Gradle
  • Grammar-Kit (for bnf compilation) version 1.2.0. (Later versions are not backward compatible with IDEA 14.)


  • JUnit

Optional, install if you want to modify lexer/parser:

IntelliJ IDEA uses the Grammar-Kit plugin to generate its lexer and parser for Haxe and HXML. The grammar file for Haxe is haxe.bnf. The grammar file for HXML is hxml.bnf.

Enable the PSI Viewer

In versions 2020 and later, the PsiViewer is not pre-installed. It can be downloaded from the marketplace. Two menu items under the Tools menu (View PSI; View PSI of Current File) will appear if the current project uses a plugin SDK. However, that is not useful when you're ''testing'' a plugin using another project. To always have the menu items available, add the following lines to the end of the ${IDEA_INSTALLATION_DIRECTORY}/bin/ file (as directed here:

# Allow the PSI viewer to be available to all projects.

Sometimes, when testing, the secondary instance of IDEA (running the plugin you're debugging) won't turn on the PSI viewer when that property is actually set. You can always enable it by adding to the "VM Options" field in the 'Run->Edit Configurations...' dialog.

Note that when you first open the project (and have the Gradle plugin installed), or if you specifically run

gradlew regenerateRunConfigurations

several run configurations will be created for you, with this option already set. (See the 'Gradle Builds' section below.)

Disable ProcessCanceledExceptions

Eventually, you may run into the frustrating situation where your stepping through sources takes longer than IDEA's timeout and will try to cancel the process you're debugging. This can be disabled by adding -Didea.ProcessCanceledException=disabled to the same "VM Options" field.

Again, the regenerateRunConfigurations Gradle task will create a run configuration with this set as well.

See JetBrains' documentation for the '' file. for other goodies and their suggested methods for modifying properties.


Do NOT install the haxe support plugin if you want to hack on it. The installed plugin will be loaded and override your newly built one. Running the "Haxe" plugin can only use the version you've built if there isn't one already in place. (Don't worry, when you are running or debugging, the plugin support is enabled in the test instance of Idea that is launched.)

Steps to configure a IntelliJ Platform Plugin SDK:

This step should no longer be necessary when using Gradle to build and run Ide and tests. The gradle-intellij-plugin should configure all necessary dependencies for you

  • Open Module Settings
  • SDKs -> + button -> IntelliJ Platform Plugin SDK -> Choose a folder with IntelliJ Ultimate(!) or *.App on Mac
  • Go to the SDK’s settings page -> Classpath tab -> + button(upper right corner or bottom left corner in IntelliJ 14) -> add plugins: flex
  • To add a plugin go to IntelliJ IDEA folder/plugins//lib and choose all jars
  • Add all libraries from <your_IDEA_install_directory>/lib directory. Do this after each upgrade, too, particularly if you see ClassNotFound exceptions when attempting to run the plugin.

Video tutorials from as3Boyan


How to write plugin code


Contributors are expected to have and build against each of the latest sub-release of each major and minor version of IDEA that is supported by the plugin team. At the time of this writing, that would be 2016.1.4, 2016.2.5, 2016.3.7, 2017.1.5, and 2017.2.6, 2017.3.3, 2018.x, and 2019.1. As new versions are released this will continue to be a moving target, as we attempt to keep up with the development community.

We do NOT expect contributors to keep up to date with EAP releases, nor does the team support them (though the plugin may work, and will usually install).

IDEA releases 2016 and later require JDK 8. Later JDKs can be used as the primary development environment if you so choose, but they are not allowed as a target environment, nor can any language features later than Java8 be used in source code targeted for release as part of this plugin.

JetBrains JRE's are recommended (and default in the project files). You can install them following the instructions at JetBrains' web site.

Gradle Builds

As we noted in the README file, you can build and test the plugin without ever installing IDEA Ultimate. The gradlew command will do everything for you. The first time you run the command for a given IDEA version it will download IDEA and all dependencies for that version. Any later executions of this command should execute much faster as it will reused the already downloaded files.

If for some reason a download gets corrupted or you run into problems building there's a set of clean tasks you can run that will removed cached versions and in most cases these will solve your problem.

To remove downloaded dependencies run (will be downloaded again next time you build).

gradlew removeTools 

To remove downloaded IDEA versions.

gradlew removeIdeaCache 

To remove compiled code and generated sources.

gradlew clean 
  • Note: The Build->Clean menu item that appears when the Android plugin is installed will NOT call gradlew clean. You must use the Gradle task to remove build artifacts.

As mentioned above it is possible to build and test the plugin without the needed to install IDEA. If you want to test the plugin in intelliJ simply run the command below and it should start a session with the IDEA version that you provide:

gradlew runIde -PtargetVersion=<IDEA_VERSION>

To verify that your changes do not break any other features you should run the test suite and verify IDEA can read the plugin

./gradlew test verifyPlugin

If those complete without error, you have a compilable set of changes which can be considered for merging.

IDEA builds

The preferred way for casual developers to build the plugin is using the build that they use for their other work. That is, casual developers shouldn't need to be using the command line at all, they should use the normal Build menu commands (or their shortcuts) that they are used to.

For these to work with IDEA you will have to tell IDEA to delegate te build job to Gradle You should find the option to do this under : Build -> Build tools -> Gradle -> Runner

gradle delegate

  • Note: For some users, delegating the build jobs to Gradle will cause a build started via the "Build->(Re)Build Project..." menu items to fail. For these users, not delegating may allow the build to succeed. In any case, running the build via the Gradle panel as stated below always works.

  • Note 2: When the Android plugin is enabled, errors are displayed by some versions of IDEA stating that some builds cannot be run and/or incompatible (Android-Gradle vs Java-Gradle projects). These messages may be eliminated by not using the Android plugin. If this is not possible, the error messages can be ignored.

  • *Note 3: There is a bug in most 2018.x versions where the Gradle task will not actually be run when using the "Build" menu commands. Instead a JetBrains compile task will be run with its output placed in a different place (and it will likely not succeed). However, that will not be used when the "Run" menu commands are used unless you are NOT delegating the build/run commands. When you start a run or debug session using the Gradle tasks (e.g. "Run->Debug RunIde"), Gradle will build and run the appropriate target in its own output directories.

The Gradle Project panel might be a bit overwhelming for those who are not used to Gradle. There are 4 Gradle tasks that you will probably use frequently and that is worth mentioning all these tasks can be found under project root (intellij-haxe):

  • build - Will build the plugin and create a plugin Jar in the root of the project.
  • test - Will build and run all tests in IDEA and show you the results in the test panel.
  • clean - Will remove all compiled and generated code.
  • runIde - Will build the plugin, prepare an sandbox and start an instance of IDEA with your plugin.

You can chose between run and debug by right clicking on the task you want to execute: gradle panel

Syntax Errors

We recommended that you build the project first before you start writing code as some parts of the project use generated code and you may experience syntax errors in your code editor; the code will however build just fine as these sources are generated when the project is built.

If you just want to generate the nessesary sources you can run the generateSources Gradle task.


When debugging, a secondary instance of IDEA starts up and loads the plugin. At that point, the original instance of IDEA is in debug mode and has all of the normal java debugging functionality. You will find yourself swapping back and forth between the two instances quite a lot. Note that it's very easy to think that IDEA has hung in the second instance, when, in reality, you have hit a breakpoint in the first instance.

It is also annoying that focus isn't necessarily changed correctly when swapping between two instances. It is helpful to reset focus by minimizing the second instance (using the mouse :/ ) and restoring it.

If, while debugging, you find that you are missing source files for the /gen tree, then you need to quit and do a local build to get those generated sources available for your tree. (On the other hand, since the files are auto-generated, they likely won't be much more help than the decompiled class files.)


Testing can be performed on the command line via Gradle, or within the IDE itself. To test on the command line, the command is:

./gradlew test -PtargetVersion=<IDEA_VERSION>

The requirements for testing the plugin are the same as for building the plugin. You can run tests within IDEA from the Gradle pane as well, with the output being identical to that from the command line.

If you have trouble running tests from within the IDE make sure you have configured the IDE to delegate run and build actions to Gradle as explained under IDEA builds

Running individual tests from within IDEA

When the Gradle regenerateRunConfigurations task is run, several test configurations are created which will run the unit tests via Gradle. There are four configurations that run all of the unit tests, and one, labeled 'Run Single Test' that will run a single test. You must configure the test manually, because (on 2018.x versions) IDEA's feature to run a single test will not use Gradle.

To edit the configuration, open the "Run->Edit Configurations..." dialog, select the 'Run Single Test' configuration and edit the string in the "Arguments" field from

    --tests "{replace this with FQDN of test suite or single test}"

to something like this to run a test suite

    --tests "com.intellij.plugins.haxe.ide.HaxeSemanticAnnotatorTest"

or something like this to run a single test

    --tests "com.intellij.plugins.haxe.ide.HaxeSemanticAnnotatorTest.testRemoveOverride"

Using globbing characters works, too...

    --tests "**.HaxeSemanticAnnotatorTest"

Build troubleshooting

Once in a while you might experience that your build/run/debug/test task fails and the error reported seems to be related to Gradle. This can sometimes happen when you have multiple Gradle targets open at the same time. Check your debug and run panels and try to close any extra tabs that might be open.

gradle panel

Updating Grammar Files

If you change the haxe.bnf or hxml.bnf files, you no longer have to (re)generate the parsing files; that is now done through Gradle, and Gradle will look for changes before every build, incremental or full. (It will only rebuild the files if they are out of date.)

The grammar-kit plugin is used to generate the parser files. Version 1.2.0 works well for this project and creates identical code for IDEA versions 14.0 through 2016.2. Versions 2.x work intermittently (a bug has been filed). Using 1.1.x versions, we saw a bug appear where APISs that expect discrete elements all-of-a-sudden change to requiring list type return values, or vice versa. If you see this type of error and find yourself fixing non-generated code to match the generated code, don't do it. You will find yourself changing it back and forth. The quickest workaround for the bug is to restart IDEA. That usually fixes it. Since the bug is intermittent, it may work one or a hundred times just to start failing. (We've never seen it recover.) That said, version 1.2.0 and later appear stable. However, they use the list-based APIs, so we have converted the code to that style, however incorrect it may be.

To regenerate, make your changes to the .bnf files and build the project, either via IDEA or the command line. That simple. Parser files will be generated to the project's /gen tree. Since the /gen tree is no longer checked into the source tree, you don't have to worry about copyrights, etc. Just don't try and add them back into the git repository.

Contributing your changes



  • Minimize overhead
  • Define the process concretely, so that we can agree on how to work together.
  • Document this so that the community can easily help.

Where we are working:

  • Future work will take place on the HaxeFoundation/intellij-haxe/develop branch (really, using short-lived local branches off of that).

Where we will release:

  • Releases will (usually, simultaneously) occur on the HaxeFoundation/intellij-haxe repo, and the IDEA plugin repository. Releases will be made through the github release mechanism. Binary output (e.g. intellij-haxe.jar) is no longer kept in the source tree in the repository.

How we will release:

  • When appropriate (there are changes that merit a new version), we will update the release notes, commit, tag the build, and create a release on the HaxeFoundation/intellij-haxe GitHub repository. Updating the release notes primarily means adding release notes to src/META-INF/plugin.xml, and echoing them to
  • A github "release" will be created on the HaxeFoundation/intellij-haxe repository. Binary (.jar) files for all currently built Idea target versions of the plugin will be added to the release.
  • The released plugin (.jar files) will be uploaded to the JetBrains IntelliJ IDEA plugin repository.

Release environments:

  • Haxe Foundation releases will be built and smoke tested for the following environments:
    OS: Linux(Latest Ubuntu LTS), macOS(OSX), Windows
    JVM: Sun Java 1.8 compilers
    IDEA versions: 2016.3.7, 2017.1.5, 2017.2.6, 2017.3.3, 2018.1.3.
  • JetBrains repository versions will be copies of the Haxe Foundation releases.

Who will test:

  • Interested Community members will test the HaxeFoundation release environments.
    Community members will ensure that the product can be loaded into the various environments prior to release. Lack of interest from the community may delay releases.

Unit tests:

  • Unit tests will be run and must pass with every commit. We are using Travis-CI and AppVeyor to automate this process. No merge will be considered or approved unless it passes unit tests cleanly.

Release Timing

As far as updates the IDEA repository go, the team will agree on releases as necessary and as critical errors are fixed. Optimally, we should create a release about every month to six weeks.

Release Process

Once we have a stable code base and would like to create a release, you should get consensus from the current primary developers. Once you have agreement on the release number, this is the process:

  1. Make sure that all relevant outstanding pull requests have been merged into the master branch. (Generally speaking, pull all changes from the develop branch.)

  2. Review the git change log and make sure that all relevant updates are reflected in the plugin's change log. The change log appears in two places: src/META-INF/plugin.xml and The former is what the IDEA user will see in the plugin description page and in the IDEA plugin repository. The latter is what github users will see. You will also need the change log for the releases page later on. To keep things in sync, it is easiest to edit the plugin.xml, then copy the relevant section to

  3. Update the file: ./ in the project root.

  4. Commit the change logs, merge them into master, and then pull the master branch locally so that you can test and tag it.

  5. Build each of the releases: For each release, run the Gradle build task (or your local equivalent)

    • ./gradlew buildPlugin -PtargetVersion=2018.3.6
    • ./gradlew buildPlugin -PtargetVersion=2019.3.5
    • ./gradlew buildPlugin -PtargetVersion=2020.2.1
  6. Smoke test each of the releases. A smoke test includes installing the releases in a primary (NOT debug) instance of IDEA and verifying basic functionality:

    • Reload a project
    • Compile a project
    • Show class hierarchy
    • Copy/Paste a block
    • Invoke completion
    • Visually verify coloring
    • Goto definition
    • Find occurrences
    • Start the debugger
    • Run the project
  7. Run the unit tests on all versions:

    • ./gradlew test -PtargetVersion=2018.3.6, etc.
  8. Tag the commit using the agreed upon release number: git tag -a 0.9.5 -m "Release 0.9.5"

  9. Push the release back up to master: git push origin master; git push --tags origin master

  10. Create a release on github, using the tag you just created:

    • Sign in and draft a new release, using the tag you just added.
    • Upload all of the release jars to the github release page.
    • Add the change notes for the most recent changes (between this release and the last).
    • Mark it as pre-release if appropriate.
    • Submit
  11. Upload the jars to the IDEA plugin repository

Code Review and Commit Process

We, as a team, are reviewing each other’s code publicly on github. To do so we’re using the common git practice of creating short-lived work branches, and then creating pull requests.

Here’s how:

  1. Create a new (or use an existing) branch for any work that you do. The base branch for new changes should always be 'develop'. The critical thing here is not to do your work directly on the stable, master, or develop branches.
  2. Make and test your changes.
  3. Create unit tests for your changes. (See the testSrc and testData directories for examples.)
  4. Update src/META-INF/plugin.xml with the change description in the top (Usually "Unreleased changes" section).
  5. When your work is complete, merge current sources from the develop branch up to your branch, re-test locally, then push your branch to HaxeFoundation/intellij-haxe. Travis-CI will automatically start a build and test cycle applying your changes against the develop branch.
  6. Create a pull request (against the develop branch, not master), and wait for comments.
  7. If you get comments that require changes, address those and return to step 2.
  8. When you get an “OK to merge,” or "approved," message from anyone on the team: Eric, @EricBishton; (others as they become regular contributors,) go ahead and merge your changes to develop. A clean merge requires no further testing, as Travis-CI will do it for you. However any build break must be addressed immediately. A build that has conflicts requires manual resolution and must be re-tested locally prior to push. For regular team members, the original requester will be the person to merge since they are best suited to address conflicts. Merges from occasional contributors will be merged by a team member as time and resource becomes available.
  9. Check the Travis-CI output ( to ensure that everything built correctly.