[themes] Support ${preferredTheme} as theme setting

“workbench.colorTheme” should not be in the user settings if the automatic dark-mode switch is on. Or at least it shouldn’t be changed by vscode for the user.

That file is for me to tell vscode what to do. Not for vscode to tell me what it did.

My dotfiles are changing depending on the time of day now, and that’s not the way it should be.

• VSCode Version: 1.42.1
• OS Version: macOS 10.15.3

Copied from about:

Version: 1.42.1
Commit: c47d83b293181d9be64f27ff093689e8e7aed054
Date: 2020-02-11T14:44:27.652Z
Electron: 6.1.6
Chrome: 76.0.3809.146
Node.js: 12.4.0
V8: 7.6.303.31-electron.0
OS: Darwin x64 19.3.0

Steps to Reproduce:

1. Make settings like:

"window.autoDetectColorScheme": true,
"workbench.preferredDarkColorTheme": "Base16 Dark Eighties",
"workbench.preferredLightColorTheme": "Base16 Light Tomorrow",

1. Switch the dark-mode to on or off.
2. See "workbench.colorTheme": "Base16 Light Tomorrow" appear in settings. This setting shouldn’t be there, it’s not my setting. It’s vscode’s “state”.

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

[PeterMinin]

Another problem with changing the settings automatically is that if multiple VS Code windows are open, each of them tries to apply the same change to settings.json at the same time. As a result, what I’m observing is that, at theme change, all windows but one show “Failed to save ‘settings.json’: The content of the file is newer” and open a tab for settings.json with a “modified” status.

"${preferredTheme}" seems like a good solution.

[carlossanlop]

Ah, that wasn’t clear to me. The description said “Make settings like:” which led me to think the option didn’t exist. Thanks for explaining.