microsoft / microsoft/vscode-java-debug

Add Support For Showing a Custom Type View via TypeCustomDebugDataView or Annotations

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ai-triaged enhancement feature request variables
Dominant language
TypeScript
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591
Forks
429
Avg merge
1d 9h
Merged PRs (30d)
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Description

Hi,

It seems currently vscode-java-debug doesn't support a way to have different representations of a type during debug in inline view, "variables" and "watch" windows.

Environment
  • Operating System: Windows 10 19043.1645 (x64)
  • JDK version: Java 11 (Oracle JDK 16)
  • Visual Studio Code version: 1.66.2
  • Java extension version: 1.6.0
  • Java Debugger extension version: 0.40.1
Steps To Reproduce
  1. Start a debugging session in vscode for any java file.
  2. See how class variables are represented in inline-view, "variables" and "watch" windows.
Current Result

For example, here is how it looks like during debug - inline view (extension version v0.40.1):
current-inline-view

and here is overridden toString method in the Point class:
point-ovirridden

notice, I have the following options in .vscode/settings.json:

{
  "java.debug.settings.showQualifiedNames": false,
  "java.debug.settings.showToString": true,
  "java.debug.settings.showLogicalStructure": true
}

also, when I expand an array in the variable view, the nested types are not showing until I click(...):
array-list-expanded-view

It seems there are no ways to enable a custom data view for a particular types, right?

Expected Result

It would be cool to have something like that:
inline-view-expected

It seems like it can be done using either:

  1. Adding an option to enable displaying a result of overridden toString method, e.g. java.debug.settings.showToStringInlineView: true
  2. Add "Java Type Renderer" to support custom data views similar to IntellijIdea "debugger -> Customize Data Views -> Java Type Renderer" (see link #1 in Additional Informations)
  3. Add something like DebuggerDisplay annotation similar to C# DebuggerDisplayAttribute (see link #2 in Additional Informatins)

For me the second way seems more appealing because it may allow setting custom debug views even for Java internal classes like java.utils.ArrayList

Additional Informations

For example, here are some StackOverflow questions that illustrate the problem:

  1. IntelliJ change toString for debug mode (variables view) | StackOverflow
  2. Display custom string in debugger variables | StackOverflow

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

No source files, tests, or entry points are named. Start by tracing how vscode-java-debug renders values in inline, Variables, and Watch views, then compare the proposed TypeCustomDebugDataView, annotation, and toString approaches. Done means an agreed design and support for custom type representations across the requested views.

Written by the indexing model from the issue text.

Assessment

Tech stack
java, typescript
Domain
devtools
Issue type
Feature
Difficulty
5/5
Estimated time
Over a week
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
25/100

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