tab_width should fall back to indent_size

[sharwell]

Version Used: 15.1

🔗 Originally posted on developer community by Clinton Ingram (@saucecontrol?).

Steps to Reproduce:

Use the following .editorconfig file:

[*.cs]
indent_style = tab
indent_size = 16

Expected Behavior:

The editor formats code with a single hard-tab for indentation, which is displayed in the editor with a width of 16 characters. According to the EditorConfig format:

tab_width: a whole number defining the number of columns used to represent a tab character. This defaults to the value of indent_size and doesn't usually need to be specified.

Actual Behavior:

The editor formats code with multiple hard tabs for indentation.

Impacted code:

roslyn/src/Workspaces/Core/Portable/Formatting/FormattingOptions.cs

Lines 14 to 17 in a703709

	// This is also serialized by the Visual Studio-specific LanguageSettingsPersister
	public static PerLanguageOption<int> TabSize { get; } =
	new PerLanguageOption<int>(nameof(FormattingOptions), nameof(TabSize), defaultValue: 4,
	storageLocations: EditorConfigStorageLocation.ForInt32Option("tab_width"));

[sharwell]

📝 We also have an internal bug tracking editor-related functionality impacted by this interpretation of the EditorConfig file.

[MhdTlb]

Can I work on this?

[sharwell]

@MhdTlb Yes. Do keep in mind that I'm not certain this is an issue that may or may not have an easy solution. If you get stuck, let us know and we'll try to track down the right person to unblock you. 😄

[Gargaj]

This has a weird effect on the auto-formatter (Format Selection or Format Document) in that if there's a difference between tab_width and indent_size, it will use the incorrect amount of indentations.

[Eilon]

Got here from dotnet/format#574 because this affects running dotnet format where you get a weird mix of tabs and spaces in the same document. Fortunately, the workaround of setting tab_width to the same value as indent_size works.