This adds details for every ISR cache request if the page being
requested supports PPR. If it does, it'll attempt to load the
`.prefetch.rsc` payload instead of the `.rsc` payload. This corrects a
bug that was present in deployed environments.
This additionally refactors the `isAppPPREnabled` out of most of the
application, as it's only used to determine if we should add to the
`prefetchDataRoute` fields in the `prerender-manifest.json`. To support
loading the prefetch file or not, we pass the `isRoutePPREnabled`
through with the cache get/set operations instead.
x-slack-ref:
https://vercel.slack.com/archives/C075MSFK9ML/p1717094328986429
Enabling Partial Prerendering (PPR) for an entire application is
ideally, the goal for teams wanting to test out the feature or adopt it
in their applications to get ready for when it becomes the default
rendering pattern. For large applications, with many routes the new
behaviours of old API's may prove a difficult pill to swallow all at
once.
This aims to enable incremental adoption of PPR for pages and routes
that want to support it in a similar way to how existing segment-level
configurations. Segments can now add:
```ts
export const experimental_ppr = true
```
To enable PPR for that segment and those descending segments. Any subset
of those routes that have it enabled can add:
```ts
export const experimental_ppr = false
```
<details>
<summary>An aside on the choice of <code>experimental_ppr</code>
name</summary>
<blockquote>
<p>It is against common JS semantics to use snake-case, and preference
is given to camel-case instead. The choice to make this snake-case was
to re-enforce that this is an experimental feature, an ugly incremental
path, and ideally, developers should aim to remove all references of it
from their codebase.</p>
<p>Additionally, this mirrors what we've done for unstable API's like
`unstable_cache`.</p>
</blockquote>
</details>
To disable PPR for that segment and those descending segments. To use
this new option, the `experimental.ppr` configuration in
`next.config.js` must be set to `"incremental"`:
```js
// next.config.js
module.exports = {
experimental: {
ppr: "incremental",
},
}
```
If a segment does not export a `experimental_ppr` boolean, it is
inferred from it's parent. If no parent has it defined, it's default
value is `false` and therefore disabled.
Once all your segments have PPR enabled via this config, it would be
considered safe for teams to set their `experimental.ppr` value in the
`next.config.js` to `true`, enabling it for the entire app and for all
future routes.
### Aside
I also took the liberty to rename `isPPR` and `supportsPPR` to be the
clearer `isAppPPREnabled` and `isRoutePPREnabled`.
---------
Co-authored-by: Hendrik Liebau <mail@hendrik-liebau.de>
### What?
When using the file system cache with `isrMemoryCacheSize: 0`, time-based revalidation is not working, and the file is constantly updated. I have also added some debug logging to mirror that in the `fetch-cache` handler
Detailed explanation in #58507
### Why?
The cached object's tags are incorrectly accessed, causing the cache to be rewritten every hit. This is catastrophic for a caching system that relies on file modification timestamps. The tags are one level up in the object from where [they are currently being accessed](9ab8828f72/packages/next/src/server/lib/incremental-cache/file-system-cache.ts (L178)).
Below shows a cached fetch representation on disk. When written, the tags reside at `obj.tags` instead of `obj.data.tags`
```json
{
"kind": "FETCH",
"data": {
"headers": {
"connection": "keep-alive",
"content-encoding": "br",
"content-type": "application/json; charset=utf-8",
"date": "Wed, 15 Nov 2023 21:17:42 GMT",
"server": "nginx/1.18.0 (Ubuntu)",
"transfer-encoding": "chunked",
"vary": "Accept-Encoding"
},
"body": "[SNIP]",
"status": 200,
"url": "https://timeapi.io/api/Time/current/zone?timeZone=UTC"
# this is where the current code is trying to pull the tags
# "tags": [ "time-with-fetch" ]
},
"revalidate": 20,
# tags actually live here
"tags": [
"time-with-fetch"
]
}
```
Fixes#58507
This passes down the route kind information to the incrememntal cache so it no longer needs to test some files existing in order to validate if the file exists or not for a route.
Optimizes how we handle cache tags for soft tags (auto-added by Next.js)
and normal tags (added manually) and adds differentiating between
`revalidatePath('/blog/first')` and page/layout.
Soft tags are not stored across cache entry and instead auto sent along
when checking cache entries. This allows us to prevent storing
exponential amounts of tags across cache entries while still having the
relationship between them so that single path revalidation can work
properly.
x-ref: [slack
thread](https://vercel.slack.com/archives/C042LHPJ1NX/p1690586837903309)
### What?
In environments where `FileSystemCache` is used, the cache for static
resources such as image files will be broken.
### Why?
Because `fs.readFile(path, 'utf8')` tries to read a file as a `string`.
### How?
Change to use `fs.readFile(path)` to always read files as binary
(`Buffer`).
