Expected behaviour

When opening and deleting a terminal the number of promises in pty-host stays the same

Actual behaviour

When opening and deleting a terminal, the number of promises in pty host seems to grow by one each time, specifically

Opening and deleting a terminal 97 times in VS Code 1.105.1:

// platform/terminal/node/terminalProcess.ts

this._ptyProcess = ptyProcess;
this._childProcessMonitor = this._register(new ChildProcessMonitor(ptyProcess.pid, this._logService));
this._childProcessMonitor.onDidChangeHasChildProcesses(value => this._onDidChangeProperty.fire({ type: ProcessPropertyType.HasChildProcesses, value }));
this._processStartupComplete = new Promise<void>(c => {
	this.onProcessReady(() => c());
});

{
  "promisesWithStackTrace": [
    {
      "count": 97,
      "properties": [
        {
          "name": "[[PromiseState]]",
          "type": "string",
          "value": "fulfilled"
        },
        {
          "name": "[[PromiseResult]]",
          "type": "undefined",
          "value": "undefined"
        }
      ],
      "originalStack": [
        "src/vs/platform/terminal/node/terminalProcess.ts:317:33",
        "src/vs/platform/terminal/node/terminalProcess.ts:248:3",
        "src/vs/platform/terminal/node/ptyService.ts:840:18",
        "src/vs/platform/terminal/node/ptyService.ts:60:12"
      ]
    }
  ],
  "isLeak": true
}

Additional information

Test script for leaked promises:

git clone [email protected]:SimonSiefke/vscode-memory-leak-finder.git &&
cd vscode-memory-leak-finder &&
npm ci &&
node packages/cli/bin/test.js --cwd packages/e2e   --only terminal.create --runs 97 --check-leaks --measure promises-with-stack-trace --run-skipped-tests-anyway --measure-after --inspect-pty-host &&
cat .vscode-memory-leak-finder-results/pty-host/promises-with-stack-trace/terminal.create.json

The script can also be run with a local vscode version by passing --vscode-version "/some/custom/path/to/vscode/scripts/code.sh".

Also, sometimes the test can be flaky, so sometimes it may only work the second time or so.

Other

Does this issue occur when all extensions are disabled?: Yes

• VS Code Version: 1.105.1
• OS Version: Ubuntu 25.04

Related: #276610