Custom themes are not displayed after export if only .md file is open

[taunnol]

How to reproduce:

1. Open your .md file with presentation, not a whole project folder
2. Add a custom theme, specify the relative path to it in the settings
3. Theme will be displayed in preview
4. Export in any format
5. The exported presentation has a default theme, no errors appear in the console

This is very confusing, since the theme is visible in the preview, and the pictures (also relative) work great.

[yhatt]

Thanks! I guess this is a misdetection of the base directory for the specified relative path when exporting Markdown via Marp CLI.

marp-vscode/src/option.ts

Lines 102 to 110 in 5dbd243

	const workspaceFolder = workspace.getWorkspaceFolder(uri)
	const parentFolder = uri.scheme === 'file' && path.dirname(uri.fsPath)
	const baseFolder = (() => {
	if (workspaceFolder) return workspaceFolder.uri
	if (parentFolder) return Uri.parse(`file:${parentFolder}`, true)
	return undefined
	})()

[yhatt]

I finally got off my backside for this long-standing issue, but unfortunately I was unable to reproduce the problem.

Since I have observed similar issues in the past, I’m marking this issue as a bug, but in order to proceed with a fix, I would need more reliable reproduction steps—such as the directory file structure and the extension preference about theme CSS.