next/dist/esm/server/app-render/collect-segment-data.js

The React Framework

/* eslint-disable @next/internal/no-ambiguous-jsx -- Bundled in entry-base so it gets the right JSX runtime. */ import { jsx as _jsx } from "react/jsx-runtime";
import { PrefetchHint, StaticPrefetchDisabled } from '../../shared/lib/app-router-types';
// eslint-disable-next-line import/no-extraneous-dependencies
import { createFromReadableStream } from 'react-server-dom-webpack/client';
// eslint-disable-next-line import/no-extraneous-dependencies
import { prerender } from 'react-server-dom-webpack/static';
// eslint-disable-next-line import/no-extraneous-dependencies
import { renderToReadableStream } from 'react-server-dom-webpack/server';
import { streamFromBuffer, streamToBuffer } from '../stream-utils/node-web-streams-helper';
import { PAGE_SEGMENT_KEY } from '../../shared/lib/segment';
import { waitAtLeastOneReactRenderTask } from '../../lib/scheduler';
import { createPromiseWithResolvers } from '../../shared/lib/promise-with-resolvers';
import { createSegmentRequestKeyPart, appendSegmentRequestKeyPart, ROOT_SEGMENT_REQUEST_KEY, HEAD_REQUEST_KEY } from '../../shared/lib/segment-cache/segment-value-encoding';
import { getDigestForWellKnownError } from './create-error-handler';
import { Phase, printDebugThrownValueForProspectiveRender } from './prospective-render-utils';
import { workAsyncStorage } from './work-async-storage.external';
const filterStackFrame = process.env.NODE_ENV !== 'production' ? require('../lib/source-maps').filterStackFrameDEV : undefined;
const findSourceMapURL = process.env.NODE_ENV !== 'production' ? require('../lib/source-maps').findSourceMapURLDEV : undefined;
function onSegmentPrerenderError(error) {
    const digest = getDigestForWellKnownError(error);
    if (digest) {
        return digest;
    }
    // We don't need to log the errors because we would have already done that
    // when generating the original Flight stream for the whole page.
    if (process.env.NEXT_DEBUG_BUILD || process.env.__NEXT_VERBOSE_LOGGING) {
        const workStore = workAsyncStorage.getStore();
        printDebugThrownValueForProspectiveRender(error, (workStore == null ? void 0 : workStore.route) ?? 'unknown route', Phase.SegmentCollection);
    }
}
/**
 * Extract the FlightRouterState, seed data, and head from a prerendered
 * InitialRSCPayload. Returns null if the payload doesn't match the expected
 * shape: a single root path with no segment prefix, which has 4 elements
 * ([tree, seedData, head, isHeadPartial], per getRSCPayload) or 3 when
 * reconstructed without the isHeadPartial flag (per instant-validation).
 */ function extractFlightData(initialRSCPayload) {
    const flightDataPaths = initialRSCPayload.f;
    // FlightDataPath is an unsound type, hence the additional checks.
    if (flightDataPaths.length !== 1 || flightDataPaths[0].length !== 3 && flightDataPaths[0].length !== 4) {
        console.error('Internal Next.js error: InitialRSCPayload does not match the expected ' + 'shape for a prerendered page during segment prefetch generation.');
        return null;
    }
    return {
        buildId: initialRSCPayload.b,
        flightRouterState: flightDataPaths[0][0],
        seedData: flightDataPaths[0][1],
        head: flightDataPaths[0][2]
    };
}
export async function collectSegmentData(isCacheComponentsEnabled, fullPageDataBuffer, staleTime, clientModules, serverConsumerManifest, prefetchInlining, hints, isUpgradeableISRFallback) {
    // Traverse the router tree and generate a prefetch response for each segment.
    // A mutable map to collect the results as we traverse the route tree.
    const resultMap = new Map();
    // Before we start, warm up the module cache by decoding the page data once.
    // Then we can assume that any remaining async tasks that occur the next time
    // are due to hanging promises caused by dynamic data access. Note we only
    // have to do this once per page, not per individual segment.
    //
    // The warm-up decode also tells us the page's own shell byte boundary (its
    // `a` field): a byte offset into fullPageDataBuffer marking the end of the
    // page's shell stage, null if the shell is identical to the full static
    // response, or undefined if the render wasn't staged (no shell exists).
    //
    // And it tells us whether the render accessed runtime data (cookies,
    // headers, fallback params, searchParams, ...): the settled value of the
    // page's embedded access flag (its `u` field). Conservatively true when
    // the page carries no flag (legacy render paths) or the decode fails.
    let pageShellByteLength = undefined;
    let runtimeDataAccessed = true;
    try {
        const pagePayload = await createFromReadableStream(// Use a stream that never closes so pending references (dynamic
        // holes) can't error the decode.
        createUnclosingPrefetchStream(streamFromBuffer(fullPageDataBuffer)), {
            findSourceMapURL,
            serverConsumerManifest
        });
        await waitAtLeastOneReactRenderTask();
        // `a` is a promise resolved mid-stream; the whole buffer is present, so
        // it resolves. undefined means the render wasn't staged (no shell).
        if (pagePayload.a !== undefined) {
            pageShellByteLength = await pagePayload.a;
        }
        if (pagePayload.u !== undefined) {
            runtimeDataAccessed = readRuntimeDataAccessed(pagePayload.u);
        }
    } catch  {}
    // All segment responses of a page share one decode of the page buffer, and
    // one `release` promise that coordinates the two serialization stages: it
    // resolves when the coordinator lets the shell-stage bytes settle into the
    // rest of the page data (see renderSegmentPrefetch, which measures each
    // response's shell boundary at that moment). Its resolved value is true
    // when the page's shell is identical to its full static response — then so
    // is every segment's, so each resolves `a` to null instead of a boundary.
    //
    // When the page has a real shell boundary the decode is staged: only the
    // shell byte prefix is enqueued now, the rest held until the release. With
    // no boundary there's nothing to stage on, so the whole buffer is decoded
    // at once and the release is resolved eagerly (segment boundaries then fall
    // out as 0 or null without any measurement).
    const release = createPromiseWithResolvers();
    let pageDataStream;
    if (typeof pageShellByteLength === 'number') {
        const prefixLength = pageShellByteLength;
        pageDataStream = new ReadableStream({
            async start (controller) {
                // The shell byte prefix decodes to the page's shell variant:
                // everything the staged page render serialized after its shell stage
                // stays a pending reference until the release enqueues the rest.
                controller.enqueue(fullPageDataBuffer.subarray(0, prefixLength));
                await release.promise;
                controller.enqueue(fullPageDataBuffer.subarray(prefixLength));
            // Intentionally never closed, like createUnclosingPrefetchStream:
            // the page stream may hold references that never resolve (dynamic
            // holes), and Flight errors if the stream closes while any are pending.
            }
        });
    } else {
        pageDataStream = createUnclosingPrefetchStream(streamFromBuffer(fullPageDataBuffer));
        release.resolve(pageShellByteLength === null);
    }
    // Create an abort controller that we'll use to stop the stream.
    const abortController = new AbortController();
    const onCompletedProcessingRouteTree = async ()=>{
        // Since all we're doing is decoding and re-encoding a cached prerender, if
        // serializing the stream takes longer than a microtask, it must because of
        // hanging promises caused by dynamic data.
        await waitAtLeastOneReactRenderTask();
        abortController.abort();
    };
    // Generate a stream for the route tree prefetch. While we're walking the
    // tree, we'll also spawn additional tasks to generate the segment prefetches.
    // The promises for these tasks are pushed to a mutable array that we will
    // await once the route tree is fully rendered.
    const segmentTasks = [];
    let treeStream;
    try {
        const prerenderResult = await prerender(// RootTreePrefetch is not a valid return type for a React component, but
        // we need to use a component so that when we decode the original stream
        // inside of it, the side effects are transferred to the new stream.
        // @ts-expect-error
        /*#__PURE__*/ _jsx(PrefetchTreeData, {
            isClientParamParsingEnabled: isCacheComponentsEnabled,
            pageDataStream: pageDataStream,
            serverConsumerManifest: serverConsumerManifest,
            clientModules: clientModules,
            staleTime: staleTime,
            segmentTasks: segmentTasks,
            onCompletedProcessingRouteTree: onCompletedProcessingRouteTree,
            prefetchInlining: prefetchInlining,
            hints: hints,
            isUpgradeableISRFallback: isUpgradeableISRFallback,
            runtimeDataAccessed: runtimeDataAccessed,
            shellStageRelease: release.promise
        }), clientModules, {
            filterStackFrame,
            signal: abortController.signal,
            onError: onSegmentPrerenderError
        });
        treeStream = prerenderResult.prelude;
        // The tree walk has spawned every segment render, each against the fully
        // available shell prefix; one task later they've flushed their shells and
        // are blocked on the release for the rest.
        await waitAtLeastOneReactRenderTask();
    } catch (error) {
        // The release still fires (finally below), so the spawned tasks run to
        // completion — but the throw skips the Promise.all that observes them.
        // Absorb their rejections so a failing task can't crash as an unhandled
        // rejection and mask this error.
        void Promise.allSettled(segmentTasks);
        throw error;
    } finally{
        // Start the second stage: settle the rest of the page data into the
        // decode so each render can measure its boundary and finish. Runs on
        // failure too, so a tree-render error can't strand the spawned tasks on
        // a release that never comes. (false is inert here: a staged page's shell
        // is always a strict prefix, and an unstaged release already resolved.)
        // TODO: I don't think it's really necessary to unblock the spawned tasks.
        // It's fine if they hang indefinitely; the tasks will be garbage collected.
        release.resolve(false);
    }
    // Write the route tree to a special `/_tree` segment.
    const treeBuffer = await streamToBuffer(treeStream);
    resultMap.set('/_tree', treeBuffer);
    // Also output the entire full page data response
    resultMap.set('/_full', fullPageDataBuffer);
    // Await the segment tasks in parallel and write the segment prefetches to
    // the result map.
    let hasPageSegment = false;
    for (const [segmentPath, buffer] of (await Promise.all(segmentTasks))){
        resultMap.set(segmentPath, buffer);
        if (segmentPath.endsWith('__PAGE__')) {
            hasPageSegment = true;
        }
    }
    if (!hasPageSegment) {
        // The build requires at least one segment path ending with __PAGE__ to
        // register the catch-all segment data route. When all page segments are
        // disabled (e.g. every leaf has runtime prefetching), no __PAGE__ entry
        // is emitted. Write a dummy entry with a path that doesn't match any
        // real route segment so the client will never request it.
        //
        // TODO: Remove the __PAGE__ requirement from the build instead of
        // working around it here. The invariant is outdated now that segments
        // can be disabled.
        resultMap.set('/todo-remove-fake-segment/__PAGE__', Buffer.alloc(0));
    }
    return resultMap;
}
/**
 * Compute prefetch hints for a route by measuring segment sizes and deciding
 * which segments should be inlined. Only runs at build time. The results are
 * written to prefetch-hints.json and loaded at server startup.
 *
 * This is a separate pass from collectSegmentData so that the inlining
 * decisions can be fed back into collectSegmentData to control which segments
 * are output as separate entries vs. inlined into their parent.
 *
 * `shouldAttemptStaticPrefetch` (computed by the caller from the prerender's
 * runtime-data tracking) is folded onto every node of the result, so the
 * manifest delivers it to every response like the other hint bits. It's
 * independent of the inlining feature: when `inlining` is false the sizing
 * pass is skipped entirely — no inlining bits are emitted — and only the
 * tree shape carrying the static-prefetch hint is built.
 *
 * Both kinds of hint have the same structure and the same lifetime — one
 * bitmask per node of the route tree, measured once per build and constant
 * for the deployment. They differ only in what they're derived from: the
 * inlining bits from the size of each segment's encoded response, the
 * static-prefetch bit from what the decoded body turned out to access.
 */ export async function collectPrefetchHints(fullPageDataBuffer, staleTime, clientModules, serverConsumerManifest, inlining, shouldAttemptStaticPrefetch) {
    // Warm up the module cache, same as collectSegmentData.
    try {
        await createFromReadableStream(streamFromBuffer(fullPageDataBuffer), {
            findSourceMapURL,
            serverConsumerManifest
        });
        await waitAtLeastOneReactRenderTask();
    } catch  {}
    // Decode the Flight data to walk the route tree.
    const initialRSCPayload = await createFromReadableStream(createUnclosingPrefetchStream(streamFromBuffer(fullPageDataBuffer)), {
        findSourceMapURL,
        serverConsumerManifest
    });
    const flightData = extractFlightData(initialRSCPayload);
    if (flightData === null) {
        return {
            hints: 0,
            slots: null
        };
    }
    const { buildId, flightRouterState, seedData, head } = flightData;
    // The hints every node starts from. The static-prefetch-attempt hint is
    // page-global (the tracking that feeds it is), so it goes on every node,
    // non-propagating — the client reads it per segment, and the runtime
    // hint merging walks the manifest tree node-by-node.
    const baseHints = shouldAttemptStaticPrefetch ? PrefetchHint.ShouldAttemptStaticPrefetch : 0;
    if (inlining === false) {
        // Prefetch inlining is disabled: nothing to measure, and no inlining
        // bits may be emitted (the client would act on them even though the
        // responses aren't bundled). Just mirror the route tree's shape with
        // the base hints on every node.
        return createUniformHintTree(flightRouterState, baseHints);
    }
    const { maxSize, maxBundleSize } = inlining;
    // Root params are forwarded once at the top level of each segment
    // response, same as the page response's own root vary params; the client
    // unions them into each segment's set at read time.
    const rootVaryParamsIterable = initialRSCPayload.r ?? null;
    // The page's staleTime iterable, forwarded into each segment response. When
    // Cache Components is off the page carries no `s`, so wrap the eager value.
    const staleTimeIterable = initialRSCPayload.s ?? createStaleTimeIterable(staleTime);
    // The page's runtime-data-access flag, forwarded into each segment
    // response's `needsRuntimeRequest`. This pass only measures sizes, so a
    // conservative already-resolved `true` stands in when the page carries
    // no `u`.
    const needsRuntimeRequest = initialRSCPayload.u ?? Promise.resolve(true);
    // This pass only measures gzip sizes for inlining hints, so nothing is
    // staged (each response's `a` falls out as the no-shell sentinel, 0), but
    // the responses are byte-identical in shape to the real ones — the point
    // of measuring. Pre-resolving false is the "nothing staged" release.
    const shellStageRelease = Promise.resolve(false);
    // Measure the head (metadata/viewport) gzip size so the main traversal
    // can decide whether to inline it into a page's bundle.
    const [, headBuffer] = await renderSegmentPrefetch(buildId, staleTimeIterable, head, HEAD_REQUEST_KEY, initialRSCPayload.h, rootVaryParamsIterable, clientModules, null, // Fallback-ness doesn't affect size, so pass false.
    false, needsRuntimeRequest, shellStageRelease);
    const headGzipSize = await getGzipSize(headBuffer);
    // Mutable accumulator: the first segment that accepts the head sets this
    // to true. Once set, subsequent segments skip the check.
    const headInlineState = {
        inlined: false
    };
    // Walk the tree with the parent-first, child-decides algorithm.
    const { node } = await collectPrefetchHintsImpl(flightRouterState, buildId, staleTimeIterable, seedData, clientModules, ROOT_SEGMENT_REQUEST_KEY, null, baseHints, maxSize, maxBundleSize, headGzipSize, headInlineState, rootVaryParamsIterable, needsRuntimeRequest, shellStageRelease);
    if (!headInlineState.inlined) {
        // No page could accept the head. Set HeadOutlined on the root so the
        // client knows to fetch the head separately.
        node.hints |= PrefetchHint.HeadOutlined;
    }
    return node;
}
// Measure a segment's gzip size and decide whether it should be inlined.
//
// These hints are computed once during build and never change for the
// lifetime of that deployment. The client can assume that hints delivered as
// part of one request will be the same during a subsequent request, given
// the same build ID. There's no skew to worry about as long as the build
// itself is consistent.
//
// In the Segment Cache, we split page prefetches into multiple requests so
// that each one can be cached and deduped independently. However, some
// segments are small enough that the potential caching benefits are not worth
// the additional network overhead. For these, we inline a parent's data into
// one of its children's responses, avoiding a separate request. The parent
// is inlined into the child (not the other way around) because the parent's
// response is more likely to be shared across multiple pages. The child's
// response is already page-specific, so adding the parent's data there
// doesn't meaningfully reduce deduplication. It's similar to how JS bundlers
// decide whether to inline a module into a chunk.
//
// The algorithm is parent-first, child-decides: the parent measures itself
// and passes its gzip size down. Each child decides whether to accept. A
// child rejects if the parent exceeds maxSize or if accepting would push
// the cumulative inlined bytes past maxBundleSize. This produces
// both ParentInlinedIntoSelf (on the child) and InlinedIntoChild (on the
// parent) in a single pass.
async function collectPrefetchHintsImpl(route, buildId, staleTimeIterable, seedData, clientModules, // TODO: Consider persisting the computed requestKey into the hints output
// so it doesn't need to be recomputed during the build. This might also
// suggest renaming prefetch-hints.json to something like
// segment-manifest.json, since it would contain more than just hints.
requestKey, parentGzipSize, // Hints every node starts from (the page-global static-prefetch-attempt
// hint); the inlining bits computed here are OR'd on top.
baseHints, maxSize, maxBundleSize, headGzipSize, headInlineState, rootVaryParamsIterable, needsRuntimeRequest, shellStageRelease) {
    // Check if static prefetching is disabled for this segment
    // (prefetch: 'force-disabled' / instant = false). Such segments act as
    // transparent pass-throughs in the bundle chain: they contribute zero
    // bytes of their own and pass parent data through to children. However,
    // they cannot be the terminal of a chain — if no child accepts the parent
    // data, the parent cannot be inlined into this segment because there's no
    // static response to carry it. See the ParentInlinedIntoSelf check below.
    //
    // Partial Prefetching segments are NOT disabled even though they may need
    // a runtime prefetch: they have static data — emitted unconditionally, so
    // the client can attempt a static prefetch before deciding whether the
    // runtime request is needed — and are measured and inlined like any other
    // segment.
    const isStaticPrefetchDisabled = ((route[4] ?? 0) & StaticPrefetchDisabled) !== 0;
    // Render current segment and measure its gzip size. Skip measurement for
    // segments with static prefetching disabled since they contribute nothing.
    let currentGzipSize = null;
    if (!isStaticPrefetchDisabled && seedData !== null) {
        const [, buffer] = await renderSegmentPrefetch(buildId, staleTimeIterable, seedData[0], requestKey, seedData[4], rootVaryParamsIterable, clientModules, null, // Size-measurement pass only; fallback-ness is irrelevant here.
        false, needsRuntimeRequest, shellStageRelease);
        currentGzipSize = await getGzipSize(buffer);
    }
    // Only offer this segment to its children for inlining if its gzip size
    // is below maxSize. Segments with static prefetching disabled have
    // nothing to offer (their slot in the bundle is null).
    const sizeToInline = currentGzipSize !== null && currentGzipSize < maxSize ? currentGzipSize : null;
    // Process children serially (not in parallel) to ensure deterministic
    // results. Since this only runs at build time and the rendering is just
    // re-encoding cached prerenders, this won't impact build times. Each child
    // receives our gzip size and decides whether to inline us. Once a child
    // accepts, we stop offering to remaining siblings — the parent is only
    // inlined into one child. In parallel routes, this avoids duplicating the
    // parent's data across multiple sibling responses.
    const children = route[1];
    const seedDataChildren = seedData !== null ? seedData[1] : null;
    let slots = null;
    let didInlineIntoChild = false;
    let acceptingChildInlinedBytes = 0;
    // Track the smallest inlinedBytes across all children so we know how much
    // budget remains along the best path. When our own parent asks whether we
    // can accept its data, the parent's bytes would flow through to the child
    // with the most remaining headroom.
    let smallestChildInlinedBytes = Infinity;
    let hasChildren = false;
    for(const parallelRouteKey in children){
        hasChildren = true;
        const childRoute = children[parallelRouteKey];
        const childSegment = childRoute[0];
        const childSeedData = seedDataChildren !== null ? seedDataChildren[parallelRouteKey] ?? null : null;
        const childRequestKey = appendSegmentRequestKeyPart(requestKey, parallelRouteKey, createSegmentRequestKeyPart(childSegment));
        // Determine what size to offer children for inlining. Normally we offer
        // our own size. But if static prefetching is disabled for this segment,
        // it has no data of its own — instead it passes the parent's offer
        // through to children. This allows a static grandparent to inline
        // through a disabled intermediate segment into a static grandchild.
        const sizeToOfferChild = isStaticPrefetchDisabled ? parentGzipSize : sizeToInline;
        const childResult = await collectPrefetchHintsImpl(childRoute, buildId, staleTimeIterable, childSeedData, clientModules, childRequestKey, // Once a child has accepted us, stop offering to remaining siblings.
        didInlineIntoChild ? null : sizeToOfferChild, baseHints, maxSize, maxBundleSize, headGzipSize, headInlineState, rootVaryParamsIterable, needsRuntimeRequest, shellStageRelease);
        if (slots === null) {
            slots = {};
        }
        slots[parallelRouteKey] = childResult.node;
        if (childResult.node.hints & PrefetchHint.ParentInlinedIntoSelf) {
            // This child accepted our data — it will include our segment's
            // response in its own. No need to track headroom anymore since
            // we already know which child we're inlined into.
            didInlineIntoChild = true;
            acceptingChildInlinedBytes = childResult.inlinedBytes;
        } else if (!didInlineIntoChild) {
            // Track the child with the most remaining headroom. Used below
            // when deciding whether to accept our own parent's data.
            if (childResult.inlinedBytes < smallestChildInlinedBytes) {
                smallestChildInlinedBytes = childResult.inlinedBytes;
            }
        }
    }
    // Leaf segment: no children have consumed any budget yet.
    if (!hasChildren) {
        smallestChildInlinedBytes = 0;
    }
    // Mark this segment as InlinedIntoChild if one of its children accepted.
    // This means this segment doesn't need its own prefetch response — its
    // data is included in the accepting child's response instead.
    let hints = baseHints;
    if (didInlineIntoChild) {
        hints |= PrefetchHint.InlinedIntoChild;
    }
    // inlinedBytes represents the total gzipped bytes of parent data inlined
    // into the deepest "inlining target" along this branch. It starts at 0 at
    // the leaves and grows as parents are inlined going back up the tree. If a
    // child accepted us, our size is already counted in that child's value.
    let inlinedBytes = didInlineIntoChild ? acceptingChildInlinedBytes : smallestChildInlinedBytes;
    // Determine which segment is responsible for the head (metadata/viewport).
    //
    // The head is assigned to the first page bundle terminal that has budget
    // room; otherwise it's outlined as a standalone response (HeadOutlined,
    // set by the caller). Head can only be inlined into a page, not a layout,
    // because pages may access additional params (e.g. searchParams) that
    // layouts cannot. It must be a bundle terminal because only bundle
    // terminals emit a static response of their own (the head bundle is
    // appended in collectSegmentDataImpl's standalone-task branch) —
    // assigning the head to an inlined segment would leave it out of every
    // static response.
    //
    // A disabled segment (prefetch: 'force-disabled' / instant = false) is
    // never a valid target — it has no response at all. A Partial Prefetching
    // segment, by contrast, DOES have a static response (see
    // isStaticPrefetchDisabled above) and is an ordinary candidate. Runtime
    // prefetching gets no special treatment here: whether the client will
    // actually issue a runtime request can't be known at build time (a static
    // prefetch attempt may prove sufficient and skip it), so the head must
    // always be reachable through the static responses — inlined into one of
    // them, or outlined.
    const isBundleTerminal = !didInlineIntoChild && !isStaticPrefetchDisabled;
    const segment = route[0];
    const isPageSegment = typeof segment === 'string' ? segment === PAGE_SEGMENT_KEY : segment[0] === PAGE_SEGMENT_KEY;
    if (!headInlineState.inlined && isBundleTerminal && isPageSegment) {
        // The head counts against the bundle budget.
        if (inlinedBytes + headGzipSize < maxBundleSize) {
            hints |= PrefetchHint.HeadInlinedIntoSelf;
            inlinedBytes += headGzipSize;
            headInlineState.inlined = true;
        }
    }
    // Decide whether to accept our own parent's data. Conditions:
    //
    // 1. The parent offered us a size (parentGzipSize is not null). It's null
    //    when the parent is too large to inline or when this is the root.
    //
    // 2. The total inlined bytes along this branch wouldn't exceed the budget.
    //    Even if each segment is individually small, at some point it no
    //    longer makes sense to keep adding bytes because the combined response
    //    is unique per URL and can't be deduped.
    //
    // 3. If this segment has static prefetching disabled, it can only accept
    //    the parent if it has successfully inlined into a child. A disabled
    //    segment is a transparent pass-through — it passes parent data through
    //    to descendants. But if no descendant accepted, there's no static
    //    response to carry the parent's data, so the parent must remain
    //    outlined.
    //
    // A node can be both InlinedIntoChild and ParentInlinedIntoSelf. This
    // happens in multi-level chains: GP → P → C where all are small. C
    // accepts P (P is InlinedIntoChild), then P also accepts GP (P is
    // ParentInlinedIntoSelf). The result: C's response includes both P's
    // and GP's data. The parent's data flows through to the deepest
    // accepting descendant.
    if (parentGzipSize !== null) {
        // A disabled segment can only pass through — it needs a child to
        // ultimately accept the parent's data.
        const canAcceptParent = !isStaticPrefetchDisabled || didInlineIntoChild;
        if (canAcceptParent && inlinedBytes + parentGzipSize < maxBundleSize) {
            hints |= PrefetchHint.ParentInlinedIntoSelf;
            inlinedBytes += parentGzipSize;
        }
    }
    return {
        node: {
            hints,
            slots
        },
        inlinedBytes
    };
}
// Mirrors the route tree's shape with the same hints on every node. Used by
// collectPrefetchHints when prefetch inlining is disabled: there are no sizes
// to measure, but the static-prefetch-attempt hint still needs a manifest
// tree — the client reads the bit per node, and the runtime hint merging
// (createFlightRouterStateFromLoaderTree) walks the manifest tree in parallel
// with the loader tree, so a bit that's missing from a node never reaches the
// corresponding segment.
function createUniformHintTree(route, hints) {
    let slots = null;
    const children = route[1];
    for(const parallelRouteKey in children){
        if (slots === null) {
            slots = {};
        }
        slots[parallelRouteKey] = createUniformHintTree(children[parallelRouteKey], hints);
    }
    return {
        hints,
        slots
    };
}
// We use gzip size rather than raw size because it better reflects the actual
// transfer cost. The inlining trade-off is about whether the overhead of an
// additional HTTP request (connection setup, headers, round trip) is worth
// the deduplication benefit of keeping a segment separate. Below some
// compressed size, the request overhead dominates and inlining is better.
// Above it, the deduplication benefit of a cacheable standalone response
// wins out.
async function getGzipSize(buffer) {
    const stream = new Blob([
        new Uint8Array(buffer)
    ]).stream().pipeThrough(new CompressionStream('gzip'));
    const compressedBlob = await new Response(stream).blob();
    return compressedBlob.size;
}
async function PrefetchTreeData({ isClientParamParsingEnabled, pageDataStream, serverConsumerManifest, clientModules, staleTime, segmentTasks, onCompletedProcessingRouteTree, prefetchInlining, hints, isUpgradeableISRFallback, runtimeDataAccessed, shellStageRelease }) {
    // We're currently rendering a Flight response for the route tree prefetch.
    // Inside this component, decode the Flight stream for the whole page. This is
    // a hack to transfer the side effects from the original Flight stream (e.g.
    // Float preloads) onto the Flight stream for the tree prefetch.
    // TODO: React needs a better way to do this. Needed for Server Actions, too.
    //
    // This is the decode that everything downstream reads from: the route tree
    // walk below and, through it, every segment task. When staged, the values
    // extracted here hold pending references at the param-dependent holes; the
    // shell byte prefix carries the full router tree and seed-data skeleton, so
    // the root resolves from the prefix alone (the rest arrives at the release).
    const initialRSCPayload = await createFromReadableStream(pageDataStream, {
        findSourceMapURL,
        serverConsumerManifest
    });
    const flightData = extractFlightData(initialRSCPayload);
    if (flightData === null) {
        return null;
    }
    const { buildId, flightRouterState, seedData, head } = flightData;
    // Root params are forwarded once at the top level of each segment
    // response, same as the page response's own root vary params; the client
    // unions them into each segment's set at read time.
    const rootVaryParamsIterable = initialRSCPayload.r ?? null;
    // The page's staleTime iterable, forwarded into each segment response. When
    // Cache Components is off the page carries no `s`, so wrap the eager value.
    const staleTimeIterable = initialRSCPayload.s ?? createStaleTimeIterable(staleTime);
    // The page's runtime-data-access flag, forwarded into each segment
    // response's `needsRuntimeRequest`. When the page carries no `u` (e.g.
    // legacy render paths), wrap the flag the caller read from the warm-up
    // decode in an already-resolved promise.
    const needsRuntimeRequest = initialRSCPayload.u ?? Promise.resolve(runtimeDataAccessed);
    // Only applies when prefetch inlining is enabled — the client doesn't
    // know to look for the head inside a page's response otherwise.
    const headIsInlined = prefetchInlining && hints !== null && !(hints.hints & PrefetchHint.HeadOutlined);
    // Compute the route metadata tree by traversing the FlightRouterState. As we
    // walk the tree, we will also spawn a task to produce a prefetch response for
    // each segment. When prefetch inlining is enabled, small segments are bundled
    // into their children's responses based on the hint bits.
    const headBundle = headIsInlined ? {
        rsc: head,
        varyParams: initialRSCPayload.h,
        next: null
    } : null;
    const tree = collectSegmentDataImpl(isClientParamParsingEnabled, flightRouterState, buildId, staleTimeIterable, seedData, clientModules, ROOT_SEGMENT_REQUEST_KEY, segmentTasks, prefetchInlining, hints, null, headBundle, rootVaryParamsIterable, isUpgradeableISRFallback, needsRuntimeRequest, shellStageRelease);
    // Spawn a task to produce a prefetch response for the "head" segment,
    // unless it was inlined into a page's bundle.
    if (!headIsInlined) {
        segmentTasks.push(waitAtLeastOneReactRenderTask().then(()=>renderSegmentPrefetch(buildId, staleTimeIterable, head, HEAD_REQUEST_KEY, initialRSCPayload.h, rootVaryParamsIterable, clientModules, null, isUpgradeableISRFallback, needsRuntimeRequest, shellStageRelease)));
    }
    // Notify the abort controller that we're done processing the route tree.
    // Anything async that happens after this point must be due to hanging
    // promises in the original stream.
    onCompletedProcessingRouteTree();
    // Render the route tree to a special `/_tree` segment.
    const treePrefetch = {
        tree,
        staleTime
    };
    if (buildId) {
        treePrefetch.buildId = buildId;
    }
    return treePrefetch;
}
function collectSegmentDataImpl(isClientParamParsingEnabled, route, buildId, staleTimeIterable, seedData, clientModules, requestKey, segmentTasks, prefetchInlining, hintTree, parentBundle, headBundle, rootVaryParamsIterable, isUpgradeableISRFallback, needsRuntimeRequest, shellStageRelease) {
    // Union the hints already embedded in the FlightRouterState with the
    // separately-computed build-time hints. During the initial build, the
    // FlightRouterState was produced before collectPrefetchHints ran, so
    // inlining hints (ParentInlinedIntoSelf, InlinedIntoChild) won't be in
    // route[4] yet. On subsequent renders the hints are already in the
    // FlightRouterState, so the union is idempotent.
    //
    // Always strip InliningHintsStale from the result. That bit is only
    // relevant for the initial RSC payload baked into HTML — the /_tree
    // response produced here always has correct hints, so the client should
    // never see InliningHintsStale in a /_tree response.
    const prefetchHints = ((route[4] ?? 0) | (hintTree !== null ? hintTree.hints : 0)) & ~PrefetchHint.InliningHintsStale;
    // The params this segment's own output varies on, forwarded into its
    // response as-is. Root params are forwarded separately, once per response.
    const varyParams = seedData !== null ? seedData[4] : null;
    // If static prefetching is disabled for this segment
    // (prefetch: 'force-disabled' / instant = false), it still participates in
    // the bundle chain but with null data. The client will skip creating a
    // cache entry for it.
    //
    // Partial Prefetching segments are NOT disabled even though they may need
    // a runtime prefetch: their static data is emitted UNCONDITIONALLY — it
    // can't be gated on the ShouldAttemptStaticPrefetch hint, because the
    // client walks bundles positionally and the null-slot positions must be
    // deterministic from build-time config alone. The client uses the data to
    // attempt a static prefetch before deciding whether the segment's runtime
    // request is actually needed.
    const staticPrefetchDisabled = (prefetchHints & StaticPrefetchDisabled) !== 0;
    const rsc = seedData !== null && !staticPrefetchDisabled ? seedData[0] : null;
    // Determine whether this segment's data should be accumulated into a
    // child's response (inlining) or spawned as its own task. When inlining
    // is disabled, the hint bits may still be set (they're computed at build
    // time regardless) but we ignore them — every segment is rendered
    // standalone because the client doesn't know how to parse bundled
    // responses.
    let childBundle = null;
    if (prefetchInlining && prefetchHints & PrefetchHint.InlinedIntoChild) {
        // This segment is small enough that its data will be included in one
        // of its children's responses. Don't spawn a separate task — prepend
        // this segment's data onto the linked list so the accepting child can
        // bundle it into its response.
        if (seedData !== null) {
            childBundle = {
                rsc,
                varyParams,
                next: parentBundle
            };
        }
    } else {
        // This segment is not inlined into a child. Spawn a task to render it.
        // If it has ParentInlinedIntoSelf, the accumulated parents are included
        // in its response. Otherwise parentBundle is null and it renders as a
        // standalone single-segment response.
        //
        // Skip spawning a task if rsc is null (disabled segment) — there's no
        // data to serve and the client won't request it.
        if (seedData !== null && rsc !== null) {
            let bundle = prefetchHints & PrefetchHint.ParentInlinedIntoSelf ? parentBundle : null;
            // If this page accepts the head, append it at the tail of the chain.
            if (headBundle !== null && prefetchHints & PrefetchHint.HeadInlinedIntoSelf) {
                headBundle.next = bundle;
                bundle = headBundle;
            }
            segmentTasks.push(waitAtLeastOneReactRenderTask().then(()=>renderSegmentPrefetch(buildId, staleTimeIterable, rsc, requestKey, varyParams, rootVaryParamsIterable, clientModules, bundle, isUpgradeableISRFallback, needsRuntimeRequest, shellStageRelease)));
        }
    // childBundle stays null — reset the accumulator for children.
    }
    // Metadata about the segment. Sent as part of the tree prefetch. Null if
    // there are no children.
    let slotMetadata = null;
    const children = route[1];
    const seedDataChildren = seedData !== null ? seedData[1] : null;
    for(const parallelRouteKey in children){
        const childRoute = children[parallelRouteKey];
        const childSegment = childRoute[0];
        const childSeedData = seedDataChildren !== null ? seedDataChildren[parallelRouteKey] ?? null : null;
        const childRequestKey = appendSegmentRequestKeyPart(requestKey, parallelRouteKey, createSegmentRequestKeyPart(childSegment));
        const childHintTree = hintTree !== null && hintTree.slots !== null ? hintTree.slots[parallelRouteKey] ?? null : null;
        const childTree = collectSegmentDataImpl(isClientParamParsingEnabled, childRoute, buildId, staleTimeIterable, childSeedData, clientModules, childRequestKey, segmentTasks, prefetchInlining, childHintTree, childBundle, headBundle, rootVaryParamsIterable, isUpgradeableISRFallback, needsRuntimeRequest, shellStageRelease);
        if (slotMetadata === null) {
            slotMetadata = {};
        }
        slotMetadata[parallelRouteKey] = childTree;
    }
    const segment = route[0];
    let name;
    let param;
    if (typeof segment === 'string') {
        name = segment;
        param = null;
    } else {
        name = segment[0];
        param = {
            type: segment[2],
            // This value is omitted from the prefetch response when cacheComponents
            // is enabled.
            key: isClientParamParsingEnabled ? null : segment[1],
            siblings: segment[3]
        };
    }
    // Metadata about the segment. Sent to the client as part of the
    // tree prefetch.
    return {
        name,
        param,
        prefetchHints,
        slots: slotMetadata
    };
}
/**
 * Renders one segment prefetch response, and with it a shell byte boundary
 * (`a`) — the per-segment analogue of the route-level `a`. The boundary lets a
 * client later truncate the buffered response and re-decode the prefix into
 * the segment's shell variant (param-dependent content reduced to pending
 * references) without a second request.
 *
 * That boundary is the whole reason this isn't a plain re-serialize. A shell
 * is a temporal property of the staged page render, already collapsed by the
 * time the page stream is decoded, so it can't be recovered from the settled
 * values. Instead the response is serialized against a staged decode of the
 * page (the caller drip-feeds it in two stages): the shell rows flush first,
 * and the byte count when the rest is released is the boundary.
 *
 * Uses the streaming renderer, not `prerender`, because the boundary must be
 * observed mid-stream — `prerender` only exposes its prelude once finished.
 */ async function renderSegmentPrefetch(buildId, staleTime, rsc, requestKey, varyParams, rootVaryParams, clientModules, bundle, isUpgradeableISRFallback, needsRuntimeRequest, shellStageRelease) {
    const streamInfoStage = createPromiseWithResolvers();
    // Build the data array by walking the bundle list, terminal (requested)
    // segment first. Always an array, even for a single segment; the terminal
    // always has non-null rsc — disabled segments are skipped by the caller.
    const data = [];
    let node = {
        rsc,
        varyParams,
        next: bundle
    };
    while(node !== null){
        const elementRsc = node.rsc;
        if (elementRsc === null) {
            // Static prefetching disabled (prefetch: 'force-disabled'; Partial
            // Prefetching segments carry real data): a null placeholder keeps the
            // array aligned with the client's bundle list, which skips a cache
            // entry for the slot.
            data.push(null);
        } else {
            // We can determine if a segment contains only partial data if it takes
            // longer than a task to encode, because dynamic data is encoded as an
            // infinite promise. We must do this in a separate Flight prerender from
            // the one that actually generates the prefetch stream because we need
            // to include the result in the stream itself.
            const contentIsComplete = new Promise(async (resolve)=>{
                // Wait for the input stream to be fully unblocked before checking if
                // the data can be decoded synchronously.
                await streamInfoStage.promise;
                // If the data is fully static, this will resolve synchronously.
                // Otherwise, the promise stays unresolved forever, and so does
                // whatever field it's encoded into in the outer response.
                await prerender(elementRsc, clientModules, {
                    filterStackFrame,
                    onError () {}
                });
                resolve();
            });
            data.push({
                rsc: elementRsc,
                isPartial: contentIsComplete,
                staleTime,
                varyParams: node.varyParams
            });
        }
        node = node.next;
    }
    const responseKey = requestKey === ROOT_SEGMENT_REQUEST_KEY ? '/_index' : requestKey;
    // `a` (see SegmentPrefetchResponse['a']) is resolved below, once the shell
    // stage's bytes have been counted.
    let totalByteLength = 0;
    const shellByteOffset = createPromiseWithResolvers();
    // Wrap in the response envelope with the build ID at the top level.
    const payload = {
        buildId: buildId ?? '',
        data,
        isUpgradeableISRFallback,
        a: shellByteOffset.promise,
        rootVaryParams,
        needsRuntimeRequest
    };
    const abortController = new AbortController();
    const segmentStream = renderToReadableStream(payload, clientModules, {
        filterStackFrame,
        signal: abortController.signal,
        onError (error) {
            if (abortController.signal.aborted) {
                // Expected: aborting the render "errors" every reference that is
                // still pending, i.e. the dynamic holes. The corresponding error
                // rows are discarded below.
                return undefined;
            }
            return onSegmentPrerenderError(error);
        }
    });
    // Consume the stream as it's emitted, counting bytes so the shell boundary
    // can be measured. Reads settle within a microtask of each enqueue, so by
    // the time the release resolves (in a task after the renderer's last
    // flush), every byte the renderer has emitted has been counted.
    const reader = segmentStream.getReader();
    const chunksPromise = new Promise(async (resolve)=>{
        const chunks = [];
        while(true){
            const { done, value } = await reader.read();
            if (done) {
                break;
            }
            if (abortController.signal.aborted) {
                continue;
            }
            chunks.push(value);
            totalByteLength += value.byteLength;
        }
        resolve(chunks);
    });
    // The release's value is true when the page's shell is its entire static
    // response — then so is every segment's, so `a` is null (no separate shell
    // to extract). Otherwise we measure.
    const shellIsFullResponse = await shellStageRelease;
    // The shell stage is complete: everything the render can emit from the shell
    // prefix has flushed, so this is the shell's byte length.
    const byteLengthAfterShellStage = totalByteLength;
    // Wait one task for the rest of the segment data (past the page's own shell
    // boundary) to flush, per the timing rule: one macrotask after the release
    // enqueues it into the input decode, the render has emitted all of it.
    await waitAtLeastOneReactRenderTask();
    // Resolve `a`: null when the page said its shell is the whole response
    // (shellIsFullResponse) — then so is every segment's. Otherwise resolve the
    // measured boundary, even if no segment *content* follows it: the
    // stage-dependent metadata (`staleTime`, `needsRuntimeRequest`) always
    // lands its post-shell values and completion rows after this point, so a
    // truncated decode is meaningful for every segment of a staged page. When
    // the page wasn't staged at all, the release resolved before any bytes
    // flushed and the measured boundary falls out as 0, the "no shell"
    // sentinel.
    if (shellIsFullResponse) {
        shellByteOffset.resolve(null);
    } else {
        shellByteOffset.resolve(byteLengthAfterShellStage);
    }
    // Now write the stream metadata (`a`, the `isPartial` promises, and a
    // post-shell `needsRuntimeRequest` resolution). This is gated behind
    // streamInfoStage so it lands strictly after the boundary measurement
    // above — the post-shell values must not count as (or leak into) the
    // shell prefix.
    streamInfoStage.resolve();
    // Wait for the metadata rows to flush before halting — two macrotasks,
    // each a distinct hop:
    //   1. streamInfoStage unblocks the completeness probe renders; a static
    //      segment's probe resolves within this task (a partial one never does,
    //      which is how it stays pending → read as partial).
    //   2. those resolutions (and the already-resolved `a`) ping the render,
    //      which emits their rows; the consumer reads that chunk here.
    // Halting after only the first hop would drop the not-yet-flushed metadata.
    await waitAtLeastOneReactRenderTask();
    await waitAtLeastOneReactRenderTask();
    // We're done writing, so we can abort the stream.
    abortController.abort();
    return [
        responseKey,
        Buffer.concat(await chunksPromise)
    ];
}
/**
 * Reads the page's runtime-data-access flag (the payload's `u`) from a decode
 * of the fully-settled page buffer. Because every byte is present, the
 * promise's row (if the render emitted one) is already visible on its
 * thenable status, so this never blocks — the same trick the client cache
 * uses to read staleTime from a buffered response.
 *
 * - fulfilled: the recorded flag.
 * - pending: `false`. A successful render always settles the flag (prerender
 *   completion resolves `false`), so a pending row can only appear in a