microsoft / microsoft/vscode-java-debug
Cannot check array[0].lengh variable in debugger
Nobody has claimed this yet.
- Dominant language
- TypeScript
- Stars
- 591
- Forks
- 429
- Avg merge
- 1d 9h
- Merged PRs (30d)
- 19
Description
Hi everyone.
I have an issue when trying to debug a program that contains 2D array. If I try to put breakpoints checking for array[0].length, it fails with:
Breakpoint condition 'array[0].length > 0' error: Cannot evaluate because of compilation error(s): length cannot be resolved or is not a field.
After somme diggining, it seems that the debugger considers the array[0] object as a double:
Breakpoint condition 'array[0][0] == 0' error: Cannot evaluate because of compilation error(s): The type of the expression must be an array type but it resolved to double.
Do you have any idea on how to solve this?
Thanks
Nicolas
Environment
- Operating System: Ubuntu 22.04.3 LTS
- JDK version:
openjdk 19.0.2 2023-01-17
OpenJDK Runtime Environment (build 19.0.2+7-Ubuntu-0ubuntu322.04)
OpenJDK 64-Bit Server VM (build 19.0.2+7-Ubuntu-0ubuntu322.04, mixed mode, sharing)
- Visual Studio Code version:
Version: 1.81.1
Commit: 6c3e3dba23e8fadc360aed75ce363ba185c49794
Date: 2023-08-09T22:18:39.991Z
Electron: 22.3.18
ElectronBuildId: 22689846
Chromium: 108.0.5359.215
Node.js: 16.17.1
V8: 10.8.168.25-electron.0
OS: Linux x64 6.2.0-26-generic snap
- Java extension version: Java Extension Pack (v0.25.13)
- Java Debugger extension version: v0.53.0
Steps To Reproduce
- Add in Watch
array.length - Add in Watch
array[0].length - Add coniditional breakpoint in line 15:
array[0].length > 0
Current Result
Breakpoint condition 'array[0].length > 0' error: Cannot evaluate because of compilation error(s): length cannot be resolved or is not a field.
Expected Result
Debugger should stop on breakpoint without error
Files
Code source: TestDebugger.java.txt
Log file:
client.log.2023-08-24.txt
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start by running the attached TestDebugger.java.txt reproduction in VS Code and inspect client.log.2023-08-24.txt alongside the debugger expression-evaluation behavior for array.length and array[0].length. Done means watch expressions and the conditional breakpoint involving array[0].length evaluate without errors.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- java, typescript, vscode
- Domain
- devtools
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 45/100