[Bug]: Storysource addon fills the console with warnings

[fzaninotto]

Describe the bug

1. Go to https://react-admin-storybook.vercel.app/
2. Open the console
3. See the warning:

Warning: Encountered two children with the same key, code-segment0. Keys should be unique so that components maintain their identity across updates. Non-unique keys may cause children to be duplicated and/or omitted — the behavior is unsupported and could change in a future version.

This warning disappears as soon as the storysource addon is removed.

To Reproduce

1. Clone https://github.com/marmelab/react-admin
2. run yarn
3. run yarn storybook

System

No response

Additional context

The problem seems to come from here:

storybook/code/addons/storysource/src/StoryPanel.tsx

Lines 136 to 144 in 7c21c34

	parts.push(...start);
	parts.push(storyPart);
	lastRow = last;
	});
	const lastPart = createPart({ rows: rows.slice(lastRow), stylesheet, useInlineStyles });
	parts.push(...lastPart);

The first and the last 'part' have the same key

[asso1985]

Most likely is this line right?

storybook/code/addons/storysource/src/StoryPanel.tsx

Line 86 in f94366e

key: `code-segment${i}`,

[hudochenkov]

This is also happening in Storybook 7.6.7. Even when “Show addons” is not enabled, but “Code” tab in addons panel was the last opened:

Warnings appear also on Docs page with Docs addon.

To hide warnings we need to switch from Code tab in the addons panel and refresh the page.