ISR + Suspense Fallback Scenarios

These demos illustrate the behavior of suspense fallbacks in multiple scenarios with some unexpected outcomes.

tl:dr

Compare the behavior of these posts. After loading each page, refresh and observe the suspense fallbacks:

• post 1 with gSP, 2 suspense boundaries above
• post 2 w/o explicit gSP, 2 suspense boundaries above
• post 2 w/o explicit gSP, 1 suspense boundary above

Also note that the presence of 2 suspense boundaries allows instant navigation to the posts, where we'd have expected typical blocking ISR behavior for non-prerendered routes.

The general set up is as follows:

Exhibit A & B

• layout.tsx in /[lang] route
  • uses generateStaticParams with [{lang: "en"}]
  • top-level navigation
• 2 child routes /demo1 and /demo2, each with their own layout.tsx
  • layouts have left-nav for child routes
  • each has a post listing page
  • each has two child routes for post detail /dynamic/[postId] and /static/[postId]
    • each uses generateStaticParams with [{postId: "1"}]

Exhibit A

• /[lang]/layout.tsx top-level nav wrapped w/ suspense

/demo1

• left nav is not wrapped w/ suspense

/demo2 <-- unexpected behavior

• left nav is wrapped w/ suspense

Exhibit B

• /[lang]/layout.tsx top-level nav not wrapped w/ suspense

/demo1

• left nav is not wrapped w/ suspense

/demo2

• left nav is wrapped /w suspense

Summary

Exhibit	Demo	Post Type	Suspense Areas	Behavior	Notes
A	1	Dynamic Posts	root nav, post content	expected
A	1	Static Posts	root nav, post content	expected	with blocked nav :/
A	2	Dynamic Posts	root nav, left nav, post content	unexpected
A	2	Static Posts	root nav, left nav, post content	unexpected
B	1	Dynamic Posts	post content	expected
B	1	Static Posts	post content	expected	with blocked nav :/
B	2	Dynamic Posts	left nav, post content	expected
B	2	Static Posts	left nav, post content	expected	with blocked nav :/