Fix onDidChangeExecutionDetails API to fire taking auto selected interpreter in account

Environment data

• VS Code version: 1.53.2
• Extension version: v2021.2.582707922
• OS and version: macOS 10.15.7
• Python version: pyenv, Python 3.9
• Type of virtual environment used: venv
• Value of the python.languageServer setting: pylance

Expected behaviour

getExecutionDetails should return the active interpreter, or the extension API should have a way to signal when the active interpreter information is available after initialization is complete.

Actual behaviour

When the Python extension has just been activated, getExecutionDetails returns ‘python’, even though an interpreter is selected for the current workspace. Subsequently, onDidChangeExecutionDetails is NOT called. However, a few seconds later (when the Python extension has presumably finished initializing), getExecutionDetails finally returns the correct executable.

Steps to reproduce:

1. Make sure the python.pythonPath setting is not being used (the DeprecatedPythonPath experiment should be active).

2. Create a test workspace with some Python file and set the active interpreter to a non-default value (e.g. a venv for that workspace).

3. Create an extension using yo code. Change activationEvents to "onLanguage:python". Replace the code in extension.ts with the following:

import * as vscode from 'vscode';

export async function activate(context: vscode.ExtensionContext): Promise<void> {
	const outputChannel = vscode.window.createOutputChannel('test');
	context.subscriptions.push(outputChannel);
	const pythonExtension = vscode.extensions.getExtension('ms-python.python');
	if (pythonExtension === undefined) {
		outputChannel.appendLine('Python extension not found');
		return;
	}
	outputChannel.appendLine('Activate Python extension');
	await pythonExtension.activate();
	outputChannel.appendLine('Python extension activated');
	const handler = pythonExtension.exports.settings.onDidChangeExecutionDetails(
		(resource: vscode.Uri | undefined) => {
			outputChannel.appendLine(`Active interpreter changed for resource: ${resource}`);
		}
	);
	context.subscriptions.push(handler);
	outputChannel.appendLine('Listener registered');
	const folder = vscode.workspace.workspaceFolders?.[0].uri;
	const logInterpreter = async () => {
		const details = await pythonExtension.exports.settings.getExecutionDetails(folder);
		outputChannel.appendLine(`Execution details: ${JSON.stringify(details)}`);
	};
	
	logInterpreter();
	const interval = setInterval(logInterpreter, 100);
	setTimeout(() => clearInterval(interval), 5000);
}

1. Run the extension in the extension host and open the test Python workspace. In the ‘test’ Output channel, notice the output:

Activate Python extension
Python extension activated
Listener registered
Execution details: {"execCommand":["python"]}
[.....]
Execution details: {"execCommand":["/Users/matan/test/.venv/bin/python"]}
[.....]

As you can see, the interpreter path ‘changes’ (that is, it is being initialized) and the client extension has no way of knowing this (apart from polling maybe). My suggestion is making getExecutionDetails block until the interpreter is initialized from the interpreter storage, or exposing an executionDetailsInitialized event.

Logs

User belongs to experiment group 'pythonaacf'
User belongs to experiment group 'pythonSendEntireLineToREPL'
User belongs to experiment group 'pythonNotDisplayLinterPrompt'
User belongs to experiment group 'DeprecatePythonPath - experiment'
User belongs to experiment group 'ShowPlayIcon - start'
User belongs to experiment group 'ShowExtensionSurveyPrompt - control'
User belongs to experiment group 'DebugAdapterFactory - experiment'
User belongs to experiment group 'PtvsdWheels37 - experiment'
User belongs to experiment group 'UseTerminalToGetActivatedEnvVars - control'
User belongs to experiment group 'LocalZMQKernel - experiment'
User belongs to experiment group 'CollectLSRequestTiming - control'
User belongs to experiment group 'CollectNodeLSRequestTiming - experiment'
User belongs to experiment group 'EnableIPyWidgets - experiment'
User belongs to experiment group 'RunByLine - experiment'
User belongs to experiment group 'CustomEditorSupport - control'
> conda --version
> conda info --json
> pyenv root
> python3.7 ~/.vscode/extensions/ms-python.python-2021.2.582707922/pythonFiles/pyvsc-run-isolated.py -c "import sys;print(sys.executable)"
> python3.6 ~/.vscode/extensions/ms-python.python-2021.2.582707922/pythonFiles/pyvsc-run-isolated.py -c "import sys;print(sys.executable)"
> python2 ~/.vscode/extensions/ms-python.python-2021.2.582707922/pythonFiles/pyvsc-run-isolated.py -c "import sys;print(sys.executable)"
> python3 ~/.vscode/extensions/ms-python.python-2021.2.582707922/pythonFiles/pyvsc-run-isolated.py -c "import sys;print(sys.executable)"
> python ~/.vscode/extensions/ms-python.python-2021.2.582707922/pythonFiles/pyvsc-run-isolated.py -c "import sys;print(sys.executable)"
> python ~/.vscode/extensions/ms-python.python-2021.2.582707922/pythonFiles/pyvsc-run-isolated.py -c "import sys;print(sys.executable)"
> python ~/.vscode/extensions/ms-python.python-2021.2.582707922/pythonFiles/pyvsc-run-isolated.py -c "import sys;print(sys.executable)"
> python ~/.vscode/extensions/ms-python.python-2021.2.582707922/pythonFiles/pyvsc-run-isolated.py -c "import sys;print(sys.executable)"
> python ~/.vscode/extensions/ms-python.python-2021.2.582707922/pythonFiles/pyvsc-run-isolated.py -c "import sys;print(sys.executable)"
> python ~/.vscode/extensions/ms-python.python-2021.2.582707922/pythonFiles/pyvsc-run-isolated.py -c "import sys;print(sys.executable)"
> pyenv root
> pyenv root
> pyenv root
> pyenv root
> pyenv root
> pyenv root
Starting Pylance language server.
Python interpreter path: ./scripts/.venv/bin/python
> conda --version

[karrtikr]

It got closed as it wasn’t a trivial fix as mentioned in https://github.com/microsoft/vscode-python/issues/15467#issuecomment-784641625. It’s a matter for us prioritizing to fix it, or a external contributor is also welcome to take it from https://github.com/microsoft/vscode-python/pull/15504.

[matangover]

Indeed it doesn’t happen when DeprecatePythonPath is active. I think I see the bug in the code you linked to - when no workspace is affected, then workspaceUriIndex is -1 and _onConfigChanged gets called anyway.