Support for m2e source attachement on specific maven dependency

Support for m2e source attachement on specific maven dependency as it is possible in Eclipse.

Environment

• Operating System: Linux x64 5.3.0-40-generic
• JDK version: openjdk version “1.8.0_242”
• Visual Studio Code version: 1.42.1
• Java extension version: 0.57.0

Steps To Reproduce

1. add a maven dependency that doesn’t have source attached. (for exemple a system one whose systemPath only points to a .jar file)
2. try to find a way to manually attach the source to this specific dependency

Here is the project where I am running into this issue. It is not that easy to setup so I’m not sure if it will be of a great help: https://github.com/Atlaoui/ParallelProgramingInterface

Current Result

 // Failed to get sources. Instead, stub sources have been generated by the disassembler.
 // Implementation of methods is unavailable.

Expected Result

Sources correctly load and can be used for debugging.

Additional Informations

Eclipse has this particular ability to manually attach sources to maven dependencies:

But this action doesn’t modify the .classpath so it must be managed at a higher level. I tried to find a way to manually edit the .classpath to add the sources of a dependency in the m2e con classpathentry with no succes.

I also tried to set a lib classpathentry with a sourcepath field in addition to the m2e one by adding:

<classpathentry kind="lib" path="peersim-1.0.5/peersim-1.0.5.jar" sourcepath="peersim-1.0.5/src"/>

This makes the source fetching working while developing but then I can’t use vscode to run or debug the application as the classes are defined two times in my classpath. Here is the error I am getting from PeerSim in my specific project:

peersim.config.IllegalParameterException: Parameter "protocol.transport": The class peersim.transport.UniformRandomTransport appears more than once in the classpath; please check your classpath to avoid duplications.

Then I tried to exclude a dependency from the m2e container to sole this issue but I couldn’t find a way to do so.

Here is my final .classpath:

<?xml version="1.0" encoding="UTF-8"?>
<classpath>
	<classpathentry kind="src" output="target/classes" path="src/main/java">
		<attributes>
			<attribute name="optional" value="true"/>
			<attribute name="maven.pomderived" value="true"/>
		</attributes>
	</classpathentry>
	<classpathentry kind="src" output="target/test-classes" path="src/test/java">
		<attributes>
			<attribute name="optional" value="true"/>
			<attribute name="maven.pomderived" value="true"/>
			<attribute name="test" value="true"/>
		</attributes>
	</classpathentry>
	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-1.8">
		<attributes>
			<attribute name="maven.pomderived" value="true"/>
		</attributes>
	</classpathentry>
	<!-- <classpathentry kind="lib" path="peersim-1.0.5/peersim-1.0.5.jar" sourcepath="peersim-1.0.5/src"/> -->
	<!-- <classpathentry kind="lib" path="openmpi-4.0.2/ompi/mpi/java/java/mpi.jar" sourcepath="openmpi-4.0.2/ompi/mpi/java/java/mpi-src.zip"/> -->
	<classpathentry kind="con" path="org.eclipse.m2e.MAVEN2_CLASSPATH_CONTAINER">
		<attributes>
			<attribute name="maven.pomderived" value="true"/>
		</attributes>
	</classpathentry>
	<classpathentry kind="src" path="target/generated-sources/annotations">
		<attributes>
			<attribute name="optional" value="true"/>
			<attribute name="maven.pomderived" value="true"/>
			<attribute name="ignore_optional_problems" value="true"/>
			<attribute name="m2e-apt" value="true"/>
		</attributes>
	</classpathentry>
	<classpathentry kind="src" output="target/test-classes" path="target/generated-test-sources/test-annotations">
		<attributes>
			<attribute name="optional" value="true"/>
			<attribute name="maven.pomderived" value="true"/>
			<attribute name="ignore_optional_problems" value="true"/>
			<attribute name="m2e-apt" value="true"/>
			<attribute name="test" value="true"/>
		</attributes>
	</classpathentry>
	<classpathentry kind="output" path="target/classes"/>
</classpath>

Conclusion

What I am looking for is either a way to configure the .classpath according to my need, but I didn’t find the way to do so. Or a new feature in vscode-java to attach source on Maven dependencies like in eclipse.

[fbricon]

Have you tried to right click on a decompiled class:

See https://github.com/redhat-developer/vscode-java/issues/233#issuecomment-438486647

[ltorok]

@fbricon This is functional, but images not rendered. See my screenshot:

Source is attached from my local file src.zip, in JavaDoc is img as:

...
 <p>The above example will produce the following:</p>
 <p><img src="doc-files/Application.png" alt="A black circle in the top left
 corner of scene"></p>
...