Option to switch build tool after initial import of mixed gradle/maven project

[FieteO]

When opening a project for the first time, the user is presented with a dialog to choose between maven or gradle when more than one build tool is present.
Correct me if I am wrong, but afterwards there is no easy way to switch to the other build tool.

Environment

• Operating System: Ubuntu 23.10
• JDK version: openjdk version "17.0.10" 2024-01-16
• Visual Studio Code version: 1.88.0
• Java extension version: 1.29.0

Steps To Reproduce

1. Select the build tool when opening the project for the first time
2. ??

Please attach a sample project reproducing the error

P.S Only tangentially related: The Language Support for Java Output is printing the following error when opening the project using maven:

[Error - 9:33:05 PM] Apr 8, 2024, 9:33:05 PM Error occured while building workspace. Details: 
 message: The project was not built since its build path is incomplete. Cannot find the class file for de.danielbechler.diff.ObjectDiffer. Fix the build path then try building this project; code: 0; resource: /home/ubu/development/oss/rewrite-recipe-starter;
 message: The type de.danielbechler.diff.ObjectDiffer cannot be resolved. It is indirectly referenced from required type org.openrewrite.TreeVisitor; code: 16777563; resource: /home/ubu/development/oss/rewrite-recipe-starter/src/main/java/com/yourorg/AppendToReleaseNotes.java; line: 1

Is that an issue with a faulty project setup for maven in the openrewrite project or perhaps an error on the language support side?
It is compiling fine with running maven and gradle from the command line and when choosing gradle as the build tool

[rgrunber]

Once a selection is made, the option is stored in the workspace state database :

vscode-java/src/extension.ts

Lines 604 to 611 in e578b50

	} else if (activeBuildTool.toLocaleLowerCase().includes("maven")) {
	// Here we do not persist it in the settings to avoid generating/updating files in user's workspace
	// Later if user want to change the active build tool, just directly set the related settings.
	clientOptions.initializationOptions.settings.java.import.gradle.enabled = false;
	context.workspaceState.update(ACTIVE_BUILD_TOOL_STATE, "maven");
	} else if (activeBuildTool.toLocaleLowerCase().includes("gradle")) {
	clientOptions.initializationOptions.settings.java.import.maven.enabled = false;
	context.workspaceState.update(ACTIVE_BUILD_TOOL_STATE, "gradle");

, so we could probably restore the option to choose by resetting the value in

vscode-java/src/buildFilesSelector.ts

Lines 296 to 300 in e578b50

	export function cleanupProjectPickerCache(context: ExtensionContext) {
	context.workspaceState.update(PICKED_BUILD_FILES, undefined);
	context.workspaceState.update(BUILD_TOOL_FOR_CONFLICTS, undefined);
	context.workspaceState.update(IMPORT_METHOD, undefined);
	}

(and probably rename the method) , which gets triggered by "Clean Workspace Cache" (quick-pick from server status bar) or "Java: Clean Java Language Server Workspace" (command palette).

With that said, can you try what's mentioned in that comment, and just set :

{
"java.import.gradle.enabled": "...",
"java.import.maven.enabled": "..."
}

in your workspace (.vscode/settings.json) settings file ?

as a workaround ?

Update: Also, yes, if https://github.com/moderneinc/rewrite-recipe-starter is the project, then I'm seeing the same error. @snjeza any idea why ?

[FieteO]

Okay, generally changing the build tool works when setting either one of the

"java.import.gradle.enabled": false,
"java.import.maven.enabled": true

settings to true or false and then do a Java: Clean Language Server Workspace. Just reloading the window for instance is not enough to change it.

In terms of making this more accessible, maybe the Type in Java: Configure Runtimes could be made editable similar to how the Java version can be changed there:

[rgrunber]

I guess https://github.com/microsoft/vscode-java-pack/blob/main/src/java-runtime/index.ts could be updated to modify the active build tool for the particular workspace. @testforstephen , thoughts on this improvement ?

[testforstephen]

Pls note that Configure Runtime for Projects page is purely nodejs UI thing, no any Java logic. If we want to open the ability to reimport the workspace with different build tool there, this definitely requires language server to provide the command to do that.

Anyway, I think when you clean the language server workspace, Java extension should prompt and ask you to select the build tool again before importing mixed build tool workspace. If this is not the behavior, then it's a bug in vscode-java extension.

[rgrunber]

Java: Clean Language Server Workspace should clear the saved build tool selection now.