Tasks 2.0 npm run compile task as a preLaunchTask, Code won't start debugger

[ytimenkov]

• VSCode Version: Code 1.13.1 (379d2ef, 2017-06-14T18:21:47.485Z)
• tasks.json:

{
    "version": "2.0.0"
}

• launch.json

// A launch configuration that compiles the extension and then opens it inside a new window
{
    "version": "0.1.0",
    "configurations": [
        {
            "name": "Launch Extension",
            "type": "extensionHost",
            "request": "launch",
            "runtimeExecutable": "${execPath}",
            "args": ["--extensionDevelopmentPath=${workspaceRoot}" ],
            "stopOnEntry": false,
            "sourceMaps": true,
            "outFiles": [
                "${workspaceRoot}/out/*",
                "${workspaceRoot}/out/src/*",
                "${workspaceRoot}/out/test/*"
            ],
            "preLaunchTask": "run compile",
            "smartStep": true
        }
    ]
}

• Expected result: When I press F5, VS Code runs npm run compile and then starts debugger.
• Actual result:
  • When I press F5 first time VS Code just compiles and doesn't start debugger, just showing a spinning line in the status bar.
  • Subsequent attempts to run actually starts debugger and work as expected.
  • When I execute "Terminate running task" command I get error message:
    

Related to: #28235

[dbaeumer]

@ytimenkov where does the run compile task come from. Can you execute that task from F1 > Run Task ?

[dbaeumer]

Info is in #29013

[ytimenkov]

@dbaeumer This task is provided by npm built-in extension, activated when tasks.json has version 2.0.0.
I suspect there are either some glitches in handling isBackground in new tasks implementation (or it is not supported or implemented in npm extension) or tsc watch requires special parser which lets vscode know when initial job is done and task went into watch mode.

[dbaeumer]

This for addressed with the fix done for #29013. Marking as dup: #29013