Expose interpreter path using API

THIS WILL SOON BE REMOVED. CHECK https://github.com/microsoft/vscode-python/issues/12596 FOR THE UPDATED DESIGN PROPOSAL

This code snippet shows how to use the new API, could be helpful.

Update the API as follows by adding a settings section,

interface IExtensionApi {
    /**
     * Promise indicating whether all parts of the extension have completed loading or not.
     * @type {Promise<void>}
     * @memberof IExtensionApi
     */
    ready: Promise<void>;
    debug: {
        /**
         * Generate an array of strings for commands to pass to the Python executable to launch the debugger for remote debugging.
         * Users can append another array of strings of what they want to execute along with relevant arguments to Python.
         * E.g `['/Users/..../pythonVSCode/pythonFiles/ptvsd_launcher.py', '--host', 'localhost', '--port', '57039', '--wait']`
         * @param {string} host
         * @param {number} port
         * @param {boolean} [waitUntilDebuggerAttaches=true]
         * @returns {Promise<string[]>}
         */
        getRemoteLauncherCommand(host: string, port: number, waitUntilDebuggerAttaches: boolean): Promise<string[]>;
    };
    /**
     * Return internal settings within the extension which are stored in VSCode storage
     */
    settings: {
        /**
         * Returns the Python execution command corresponding to the specified resource, taking into account
         * any workspace-specific settings for the workspace to which this resource belongs.
         * E.g of execution commands returned could be,
         * * `['<path to the interpreter set in settings>']`
         * * `['<path to the interpreter selected by the extension when setting is not set>']`
         * * `['conda', 'run', 'python']` which is used to run from within Conda environments.
         * or something similar for some other Python environments.
         * @param {Resource} [resource] A resource for which the setting is asked for.
         * * When no resource is provided, the setting scoped to the first workspace folder is returned.
         * * If no folder is present, it returns the global setting.
         * @returns {(string[] | undefined)} When return value is `undefined`, it means no interpreter is set.
         * Otherwise, join the items returned using space to construct the full execution command.
         */
        getExecutionCommand(resource?: Resource): string[] | undefined;
    };
}

[DonJayamanne]

Apologies for the confusion, I understand this was discussed, my bad. Hiding my comments & the subsequent comments to avoid confusion

[brettcannon]

@DonJayamanne

• We know conda run is busted, but we don’t want to design ourselves into a corner if it does work someday
• Why won’t this work for pyenv? How it is different from any other path that may be provided?

We don’t want to own running code for other extensions, we are just exposing how to run code because we and other extensions have a need for this exact functionality. And we are definitely not going to wrap execution APIs as we would then have to mirror all options provided by Node and VS Code and that is not a business we want to be in.