DevMode, gwt-lib dependency and re-compiling changes

[timeu]

I am not sure if this is a bug or by design:

I created a reactor project for a GWT library which contains 2 modules:

• The library (packaging: gwt-lib) itself
• A sample gwt app (packaging: gwt-app) as a showcase.

Initially the sample gwt app had a simple dependency to the library (no classifier and no type declared). However when I run mvn gwt:devmode from my reactor project, changes to the library code (gwt-lib) are not picked up (re-compiled). Only changes to the sample app are re-compiled.

The debug output shows the following line:

[DEBUG] Ignoring com.github.timeu.dygraphs-gwt:dygraphs-gwt:jar:1.0.0-SNAPSHOT; neither a java-source, gwt-lib or jar:sources.

If I add a second dependency to the library with a classifier of type sources or with a type of gwt-lib changes to the library will be properly re-compiled.
I looked into the documentation and the only thing regarding this, was here:
https://tbroyer.github.io/gwt-maven-plugin/artifact-handlers.html

I also looked into the integration tests and only found the type of the dependency to be set to gwt-lib here:

gwt-maven-plugin/src/it/e2e/e2e-client/pom.xml

Line 20 in 2877b61

<type>gwt-lib</type>

This is with JDK 1.8.0_45, Maven 3.2.1 and gwt-maven-plugin 1.0-rc-2

[tbroyer]

Yes, sources from other projects in the reactor build are only added to the classpath by gwt:codeserver (and gwt:devmode) for dependencies that are known to contain sources: <classifier>sources</classifier> or <type>gwt-lib</type>. If you don't include <type>gwt-lib</type>, Maven assumes <type>jar</type> and the plugin assumes it only contains compiled classes (and resources).
Note that <type>gwt-lib</type> in a dependency doesn't necessarily mean that the project has/had <packaging>gwt-lib</packaging>. Those two gwt-lib have the same name but are different things as far as Maven is concerned (and similarly for the built-in jar, war, etc.)

Leaving this issue open as a reminder that the documentation needs improvement.

[timeu]

Great, thanks for clarifying.

Along these lines:
If I specify the dependency to the library in the sample app twice (one time with type gwt-lib and one time with jar) I get following error if I run mvn clean compile on the reactor project:

[ERROR] Failed to execute goal net.ltgt.gwt.maven:gwt-maven-plugin:1.0-rc-2:generate-module (default-generate-module) on project dygraphs-gwt-sample: Execution default-generate-module of goal net.ltgt.gwt.maven:gwt-maven-plugin:1.0-rc-2:generate-module failed. NullPointerException -> [Help 1]
....
Caused by: java.lang.NullPointerException
        at net.ltgt.gwt.maven.GenerateModuleMojo.generateInheritsFromDependencies(GenerateModuleMojo.java:242)

Not sure if this is a separate issue.

[tbroyer]

Yes it's a separate issue (likely a bug, probably due to changes in Maven in recent versions).
BTW, you should either have one gwt-lib dep, or 2 deps without classifier and with classifier=sources.

[tbroyer]

Fixed by 69ac0f3

[timeu]

Sorry to spam this issue (isn't really a separate issue) but in case somebody ran into the same issue:

IntelliJ won't import dependencies if they are using with the gwt-lib type. To fix this, one has to go to FIle -> Settings -> Maven -> Importing and add gwt-lib to the list of automatically imported dependencies.

[mahoe]

Sorry to spam this issue (isn't really a separate issue) but in case somebody ran into the same issue:

IntelliJ won't import dependencies if they are using with the gwt-lib type. To fix this, one has to go to FIle -> Settings -> Maven -> Importing and add gwt-lib to the list of automatically imported dependencies.

If we call it a problem then it's still present. I figured out that the NPE happens i.e. if you mess up the dependencies in your pom.xml with two entries for the same dependency (one with type gwt-lib and the second without any classifier). The plugin version I used for that is 1.0.0, GWT version 2.9.0, maven 3.6.3.

...just wanted to give my two cents here if someone comes by with the same problem.