showTextDocument is not respecting preview: true if user has enablePreview disabled

[DavyLandman]

Does this issue occur when all extensions are disabled?: Yes/No

• VS Code Version: 1.67.0
• OS Version: Windows 10 10.0.19044

Steps to Reproduce:

1. Set workbench.editor.enablePreview to false
2. Inside an extension, open a TextDocument via the showTextDocument api, pass in the { preview: true } option.
3. The new tab is not preview.
4. Open another file via the showTextDocument api, and again a new tab is opened, non preview.

Either this is a bug, or the manual is incorrect:

An optional flag that controls if an editor-tab shows as preview. Preview tabs will be replaced and reused until set to stay - either explicitly or through editing. The default behaviour depends on the workbench.editor.enablePreview-setting.

I would understand (but be a bit sad) if the documentation is wrong, like that maybe it should say that this flag is only working when workbench.editor.enablePreview is true. I think the preferred behavior would be that the first time this is called, and no preview tab exists, a new one is allocated, and all the following showTextDocument calls with { preview: true } will use that new preview tab regardless of the user setting.

[DavyLandman]

I've been reading the source a bit, if I understand correctly (i.e. I'm looking at the right instance of doOpenEditor), this line says that if enablePreview is set it will always be pinned, so the preview flag (which is translated to options?.pinned higher up in the stack) is ignored.

vscode/src/vs/workbench/browser/parts/editor/editorGroupView.ts

Line 999 in 91a9cf4

pinned: options?.sticky || !this.accessor.partOptions.enablePreview || editor.isDirty() || (options?.pinned ?? typeof options?.index === 'number' /* unless specified, prefer to pin when opening with index */) || (typeof options?.index === 'number' && this.model.isSticky(options.index)),

[bpasero]

Yeah, if the user has disabled preview tabs, an extension cannot enforce it. We should probably document that.

[DavyLandman]

Thank you for clarifying. I'll just have to tell users not to disable previews if they want this feature (of our extension) if they want to keep snappy cycles through files.