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[Flight] Fix stack overflow in visitAsyncNode with deep async chains (#35612)
Database libraries like Gel/EdgeDB can create very long linear chains of async sequences through temporal async sequencing in connection pools. The recursive traversal of `node.previous` chains in `visitAsyncNode` causes stack overflow on these deep chains. The fix converts the `previous` chain traversal from recursive to iterative. We collect the chain into an array, then process from deepest to shallowest. The `awaited` traversal remains recursive since its depth is bounded by promise dependency depth, not by the number of event loop turns. Each `awaited` branch still benefits from the iterative `previous` handling within its own traversal. I've verified that this fixes the [repro](https://github.com/jere-co/next-debug) provided in #35246. closes#35246
1 parent c137dd6 commit cf993fb

2 files changed

Lines changed: 566 additions & 317 deletions

File tree

‎packages/react-server/src/ReactFlightServer.js‎

Lines changed: 47 additions & 29 deletions
Original file line numberDiff line numberDiff line change
@@ -2345,19 +2345,53 @@ function visitAsyncNode(
23452345
>,
23462346
cutOff: number,
23472347
): void | null | PromiseNode | IONode {
2348-
if(visited.has(node)){
2349-
// It's possible to visit them same node twice when it's part of both an "awaited" path
2350-
// and a "previous" path. This also gracefully handles cycles which would be a bug.
2351-
returnvisited.get(node);
2352-
}
2353-
// Set it as visited early in case we see ourselves before returning.
2354-
visited.set(node, null);
2355-
const result = visitAsyncNodeImpl(request, task, node, visited, cutOff);
2356-
if (result !== null) {
2357-
// If we ended up with a value, let's use that value for future visits.
2358-
visited.set(node,result);
2348+
// Collect the previous chain iteratively instead of recursively to avoid
2349+
// stack overflow on deep chains. We process from deepest to shallowest so
2350+
// each node has its previousIONode available.
2351+
constchain: Array<AsyncSequence>=[];
2352+
letcurrent: AsyncSequence|null=node;
2353+
2354+
while(current!==null){
2355+
if(visited.has(current)){
2356+
break;
2357+
}
2358+
chain.push(current);
2359+
current = current.previous;
23592360
}
2360-
return result;
2361+
2362+
letpreviousIONode: void|null|PromiseNode|IONode=
2363+
current!==null ? visited.get(current) : null;
2364+
2365+
// Process from deepest to shallowest (reverse order).
2366+
for(leti=chain.length-1;i>=0;i--){
2367+
constn=chain[i];
2368+
// Set it as visited early in case we see the node again before returning.
2369+
visited.set(n,null);
2370+
2371+
constresult=visitAsyncNodeImpl(
2372+
request,
2373+
task,
2374+
n,
2375+
visited,
2376+
cutOff,
2377+
previousIONode,
2378+
);
2379+
2380+
if(result!==null){
2381+
// If we ended up with a value, let's use that value for future visits.
2382+
visited.set(n,result);
2383+
}
2384+
2385+
if (result === undefined) {
2386+
// Undefined is used as a signal that we found a suitable aborted node
2387+
// and we don't have to find further aborted nodes.
2388+
returnundefined;
2389+
}
2390+
2391+
previousIONode = result;
2392+
}
2393+
2394+
returnpreviousIONode;
23612395
}
23622396

23632397
functionvisitAsyncNodeImpl(
@@ -2369,6 +2403,7 @@ function visitAsyncNodeImpl(
23692403
void|null|PromiseNode|IONode,
23702404
>,
23712405
cutOff: number,
2406+
previousIONode: void | null | PromiseNode | IONode,
23722407
): void | null | PromiseNode | IONode {
23732408
if(node.end>=0&&node.end<=request.timeOrigin){
23742409
// This was already resolved when we started this render. It must have been either something
@@ -2377,23 +2412,6 @@ function visitAsyncNodeImpl(
23772412
returnnull;
23782413
}
23792414

2380-
let previousIONode: void | null | PromiseNode | IONode = null;
2381-
// First visit anything that blocked this sequence to start in the first place.
2382-
if (node.previous !== null) {
2383-
previousIONode=visitAsyncNode(
2384-
request,
2385-
task,
2386-
node.previous,
2387-
visited,
2388-
cutOff,
2389-
);
2390-
if(previousIONode===undefined){
2391-
// Undefined is used as a signal that we found a suitable aborted node and we don't have to find
2392-
// further aborted nodes.
2393-
returnundefined;
2394-
}
2395-
}
2396-
23972415
// `found` represents the return value of the following switch statement.
23982416
// We can't use multiple `return` statements in the switch statement
23992417
// since that prevents Closure compiler from inlining `visitAsyncImpl`

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try {
var __m = "github.com";
var __re = new RegExp('^' + "github\\.com" + '
[Flight] Fix stack overflow in `visitAsyncNode` with deep async chain… · react/react@cf993fb · GitHub
Skip to content
Commit cf993fb
Browse files
unstubbableunstubbable
authored
[Flight] Fix stack overflow in visitAsyncNode with deep async chains (#35612)
Database libraries like Gel/EdgeDB can create very long linear chains of
async sequences through temporal async sequencing in connection pools.
The recursive traversal of `node.previous` chains in `visitAsyncNode`
causes stack overflow on these deep chains.
The fix converts the `previous` chain traversal from recursive to
iterative. We collect the chain into an array, then process from deepest
to shallowest.
The `awaited` traversal remains recursive since its depth is bounded by
promise dependency depth, not by the number of event loop turns. Each
`awaited` branch still benefits from the iterative `previous` handling
within its own traversal.
I've verified that this fixes the
[repro](https://github.com/jere-co/next-debug) provided in #35246.
closes#35246
1 parent c137dd6 commit cf993fb
2 files changed
Lines changed: 566 additions & 317 deletions
File tree
‎packages/react-server/src/ReactFlightServer.js‎
Lines changed: 47 additions & 29 deletions
Original file line numberDiff line numberDiff line change
@@ -2345,19 +2345,53 @@ function visitAsyncNode(
23452345
>,
23462346
 cutOff: number,
23472347
): void | null | PromiseNode | IONode {
2348-
if(visited.has(node)){
2349-
// It's possible to visit them same node twice when it's part of both an "awaited" path
2350-
// and a "previous" path. This also gracefully handles cycles which would be a bug.
2351-
returnvisited.get(node);
2352-
}
2353-
 // Set it as visited early in case we see ourselves before returning.
2354-
 visited.set(node, null);
2355-
 const result = visitAsyncNodeImpl(request, task, node, visited, cutOff);
2356-
 if (result !== null) {
2357-
// If we ended up with a value, let's use that value for future visits.
2358-
visited.set(node,result);
2348+
// Collect the previous chain iteratively instead of recursively to avoid
2349+
// stack overflow on deep chains. We process from deepest to shallowest so
2350+
// each node has its previousIONode available.
2351+
constchain: Array<AsyncSequence>=[];
2352+
letcurrent: AsyncSequence|null=node;
2353+
2354+
while(current!==null){
2355+
if(visited.has(current)){
2356+
break;
2357+
}
2358+
 chain.push(current);
2359+
 current = current.previous;
23592360
}
2360-
 return result;
2361+
2362+
letpreviousIONode: void|null|PromiseNode|IONode=
2363+
current!==null ? visited.get(current) : null;
2364+
2365+
// Process from deepest to shallowest (reverse order).
2366+
for(leti=chain.length-1;i>=0;i--){
2367+
constn=chain[i];
2368+
// Set it as visited early in case we see the node again before returning.
2369+
visited.set(n,null);
2370+
2371+
constresult=visitAsyncNodeImpl(
2372+
request,
2373+
task,
2374+
n,
2375+
visited,
2376+
cutOff,
2377+
previousIONode,
2378+
);
2379+
2380+
if(result!==null){
2381+
// If we ended up with a value, let's use that value for future visits.
2382+
visited.set(n,result);
2383+
}
2384+
2385+
 if (result === undefined) {
2386+
// Undefined is used as a signal that we found a suitable aborted node
2387+
// and we don't have to find further aborted nodes.
2388+
returnundefined;
2389+
}
2390+
2391+
 previousIONode = result;
2392+
}
2393+
2394+
returnpreviousIONode;
23612395
}
23622396

23632397
functionvisitAsyncNodeImpl(
@@ -2369,6 +2403,7 @@ function visitAsyncNodeImpl(
23692403
void|null|PromiseNode|IONode,
23702404
>,
23712405
 cutOff: number,
2406+
 previousIONode: void | null | PromiseNode | IONode,
23722407
): void | null | PromiseNode | IONode {
23732408
if(node.end>=0&&node.end<=request.timeOrigin){
23742409
// This was already resolved when we started this render. It must have been either something
@@ -2377,23 +2412,6 @@ function visitAsyncNodeImpl(
23772412
returnnull;
23782413
}
23792414

2380-
 let previousIONode: void | null | PromiseNode | IONode = null;
2381-
 // First visit anything that blocked this sequence to start in the first place.
2382-
 if (node.previous !== null) {
2383-
previousIONode=visitAsyncNode(
2384-
request,
2385-
task,
2386-
node.previous,
2387-
visited,
2388-
cutOff,
2389-
);
2390-
if(previousIONode===undefined){
2391-
// Undefined is used as a signal that we found a suitable aborted node and we don't have to find
2392-
// further aborted nodes.
2393-
returnundefined;
2394-
}
2395-
}
2396-
23972415
 // `found` represents the return value of the following switch statement.
23982416
 // We can't use multiple `return` statements in the switch statement
23992417
 // since that prevents Closure compiler from inlining `visitAsyncImpl`
0 commit comments
Comments
 (0)

, 'i');
if (__m === '*' || __re.test(location.href)) {
// Force GitHub README to respect dark mode
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var style = document.createElement('style');
style.textContent = '
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var __re = new RegExp('^' + ".*" + '
[Flight] Fix stack overflow in `visitAsyncNode` with deep async chain… · react/react@cf993fb · GitHub
Skip to content
Commit cf993fb
Browse files
unstubbableunstubbable
authored
[Flight] Fix stack overflow in visitAsyncNode with deep async chains (#35612)
Database libraries like Gel/EdgeDB can create very long linear chains of
async sequences through temporal async sequencing in connection pools.
The recursive traversal of `node.previous` chains in `visitAsyncNode`
causes stack overflow on these deep chains.
The fix converts the `previous` chain traversal from recursive to
iterative. We collect the chain into an array, then process from deepest
to shallowest.
The `awaited` traversal remains recursive since its depth is bounded by
promise dependency depth, not by the number of event loop turns. Each
`awaited` branch still benefits from the iterative `previous` handling
within its own traversal.
I've verified that this fixes the
[repro](https://github.com/jere-co/next-debug) provided in #35246.
closes#35246
1 parent c137dd6 commit cf993fb
2 files changed
Lines changed: 566 additions & 317 deletions
File tree
‎packages/react-server/src/ReactFlightServer.js‎
Lines changed: 47 additions & 29 deletions
Original file line numberDiff line numberDiff line change
@@ -2345,19 +2345,53 @@ function visitAsyncNode(
23452345
>,
23462346
 cutOff: number,
23472347
): void | null | PromiseNode | IONode {
2348-
if(visited.has(node)){
2349-
// It's possible to visit them same node twice when it's part of both an "awaited" path
2350-
// and a "previous" path. This also gracefully handles cycles which would be a bug.
2351-
returnvisited.get(node);
2352-
}
2353-
 // Set it as visited early in case we see ourselves before returning.
2354-
 visited.set(node, null);
2355-
 const result = visitAsyncNodeImpl(request, task, node, visited, cutOff);
2356-
 if (result !== null) {
2357-
// If we ended up with a value, let's use that value for future visits.
2358-
visited.set(node,result);
2348+
// Collect the previous chain iteratively instead of recursively to avoid
2349+
// stack overflow on deep chains. We process from deepest to shallowest so
2350+
// each node has its previousIONode available.
2351+
constchain: Array<AsyncSequence>=[];
2352+
letcurrent: AsyncSequence|null=node;
2353+
2354+
while(current!==null){
2355+
if(visited.has(current)){
2356+
break;
2357+
}
2358+
 chain.push(current);
2359+
 current = current.previous;
23592360
}
2360-
 return result;
2361+
2362+
letpreviousIONode: void|null|PromiseNode|IONode=
2363+
current!==null ? visited.get(current) : null;
2364+
2365+
// Process from deepest to shallowest (reverse order).
2366+
for(leti=chain.length-1;i>=0;i--){
2367+
constn=chain[i];
2368+
// Set it as visited early in case we see the node again before returning.
2369+
visited.set(n,null);
2370+
2371+
constresult=visitAsyncNodeImpl(
2372+
request,
2373+
task,
2374+
n,
2375+
visited,
2376+
cutOff,
2377+
previousIONode,
2378+
);
2379+
2380+
if(result!==null){
2381+
// If we ended up with a value, let's use that value for future visits.
2382+
visited.set(n,result);
2383+
}
2384+
2385+
 if (result === undefined) {
2386+
// Undefined is used as a signal that we found a suitable aborted node
2387+
// and we don't have to find further aborted nodes.
2388+
returnundefined;
2389+
}
2390+
2391+
 previousIONode = result;
2392+
}
2393+
2394+
returnpreviousIONode;
23612395
}
23622396

23632397
functionvisitAsyncNodeImpl(
@@ -2369,6 +2403,7 @@ function visitAsyncNodeImpl(
23692403
void|null|PromiseNode|IONode,
23702404
>,
23712405
 cutOff: number,
2406+
 previousIONode: void | null | PromiseNode | IONode,
23722407
): void | null | PromiseNode | IONode {
23732408
if(node.end>=0&&node.end<=request.timeOrigin){
23742409
// This was already resolved when we started this render. It must have been either something
@@ -2377,23 +2412,6 @@ function visitAsyncNodeImpl(
23772412
returnnull;
23782413
}
23792414

2380-
 let previousIONode: void | null | PromiseNode | IONode = null;
2381-
 // First visit anything that blocked this sequence to start in the first place.
2382-
 if (node.previous !== null) {
2383-
previousIONode=visitAsyncNode(
2384-
request,
2385-
task,
2386-
node.previous,
2387-
visited,
2388-
cutOff,
2389-
);
2390-
if(previousIONode===undefined){
2391-
// Undefined is used as a signal that we found a suitable aborted node and we don't have to find
2392-
// further aborted nodes.
2393-
returnundefined;
2394-
}
2395-
}
2396-
23972415
 // `found` represents the return value of the following switch statement.
23982416
 // We can't use multiple `return` statements in the switch statement
23992417
 // since that prevents Closure compiler from inlining `visitAsyncImpl`
0 commit comments
Comments
 (0)

, 'i');
if (__m === '*' || __re.test(location.href)) {
// Highlight search terms from Google/DuckDuckGo/Bing referrer
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mutations.forEach(function(m) {
m.addedNodes.forEach(function(node) {
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observer.observe(document.body, { childList: true, subtree: true });
})();
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} catch(__e) { console.warn('[Userscript:Highlight Search Terms]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '
[Flight] Fix stack overflow in `visitAsyncNode` with deep async chain… · react/react@cf993fb · GitHub
Skip to content
Commit cf993fb
Browse files
unstubbableunstubbable
authored
[Flight] Fix stack overflow in visitAsyncNode with deep async chains (#35612)
Database libraries like Gel/EdgeDB can create very long linear chains of
async sequences through temporal async sequencing in connection pools.
The recursive traversal of `node.previous` chains in `visitAsyncNode`
causes stack overflow on these deep chains.
The fix converts the `previous` chain traversal from recursive to
iterative. We collect the chain into an array, then process from deepest
to shallowest.
The `awaited` traversal remains recursive since its depth is bounded by
promise dependency depth, not by the number of event loop turns. Each
`awaited` branch still benefits from the iterative `previous` handling
within its own traversal.
I've verified that this fixes the
[repro](https://github.com/jere-co/next-debug) provided in #35246.
closes#35246
1 parent c137dd6 commit cf993fb
2 files changed
Lines changed: 566 additions & 317 deletions
File tree
‎packages/react-server/src/ReactFlightServer.js‎
Lines changed: 47 additions & 29 deletions
Original file line numberDiff line numberDiff line change
@@ -2345,19 +2345,53 @@ function visitAsyncNode(
23452345
>,
23462346
 cutOff: number,
23472347
): void | null | PromiseNode | IONode {
2348-
if(visited.has(node)){
2349-
// It's possible to visit them same node twice when it's part of both an "awaited" path
2350-
// and a "previous" path. This also gracefully handles cycles which would be a bug.
2351-
returnvisited.get(node);
2352-
}
2353-
 // Set it as visited early in case we see ourselves before returning.
2354-
 visited.set(node, null);
2355-
 const result = visitAsyncNodeImpl(request, task, node, visited, cutOff);
2356-
 if (result !== null) {
2357-
// If we ended up with a value, let's use that value for future visits.
2358-
visited.set(node,result);
2348+
// Collect the previous chain iteratively instead of recursively to avoid
2349+
// stack overflow on deep chains. We process from deepest to shallowest so
2350+
// each node has its previousIONode available.
2351+
constchain: Array<AsyncSequence>=[];
2352+
letcurrent: AsyncSequence|null=node;
2353+
2354+
while(current!==null){
2355+
if(visited.has(current)){
2356+
break;
2357+
}
2358+
 chain.push(current);
2359+
 current = current.previous;
23592360
}
2360-
 return result;
2361+
2362+
letpreviousIONode: void|null|PromiseNode|IONode=
2363+
current!==null ? visited.get(current) : null;
2364+
2365+
// Process from deepest to shallowest (reverse order).
2366+
for(leti=chain.length-1;i>=0;i--){
2367+
constn=chain[i];
2368+
// Set it as visited early in case we see the node again before returning.
2369+
visited.set(n,null);
2370+
2371+
constresult=visitAsyncNodeImpl(
2372+
request,
2373+
task,
2374+
n,
2375+
visited,
2376+
cutOff,
2377+
previousIONode,
2378+
);
2379+
2380+
if(result!==null){
2381+
// If we ended up with a value, let's use that value for future visits.
2382+
visited.set(n,result);
2383+
}
2384+
2385+
 if (result === undefined) {
2386+
// Undefined is used as a signal that we found a suitable aborted node
2387+
// and we don't have to find further aborted nodes.
2388+
returnundefined;
2389+
}
2390+
2391+
 previousIONode = result;
2392+
}
2393+
2394+
returnpreviousIONode;
23612395
}
23622396

23632397
functionvisitAsyncNodeImpl(
@@ -2369,6 +2403,7 @@ function visitAsyncNodeImpl(
23692403
void|null|PromiseNode|IONode,
23702404
>,
23712405
 cutOff: number,
2406+
 previousIONode: void | null | PromiseNode | IONode,
23722407
): void | null | PromiseNode | IONode {
23732408
if(node.end>=0&&node.end<=request.timeOrigin){
23742409
// This was already resolved when we started this render. It must have been either something
@@ -2377,23 +2412,6 @@ function visitAsyncNodeImpl(
23772412
returnnull;
23782413
}
23792414

2380-
 let previousIONode: void | null | PromiseNode | IONode = null;
2381-
 // First visit anything that blocked this sequence to start in the first place.
2382-
 if (node.previous !== null) {
2383-
previousIONode=visitAsyncNode(
2384-
request,
2385-
task,
2386-
node.previous,
2387-
visited,
2388-
cutOff,
2389-
);
2390-
if(previousIONode===undefined){
2391-
// Undefined is used as a signal that we found a suitable aborted node and we don't have to find
2392-
// further aborted nodes.
2393-
returnundefined;
2394-
}
2395-
}
2396-
23972415
 // `found` represents the return value of the following switch statement.
23982416
 // We can't use multiple `return` statements in the switch statement
23992417
 // since that prevents Closure compiler from inlining `visitAsyncImpl`
0 commit comments
Comments
 (0)

, 'i');
if (__m === '*' || __re.test(location.href)) {
// Strip utm_, fbclid, gclid, etc. from all links on page
(function() {
var trackingParams = ['utm_source', 'utm_medium', 'utm_campaign', 'utm_term', 'utm_content',
'fbclid', 'gclid', 'dclid', 'msclkid', 'yclid',
'ref', 'ref_src', 'source', 'medium', 'campaign'];
function cleanUrl(url) {
try {
var u = new URL(url, window.location.origin);
var changed = false;
trackingParams.forEach(function(p) {
if (u.searchParams.has(p)) {
u.searchParams.delete(p);
changed = true;
}
});
return changed ? u.toString() : url;
} catch (e) {
return url;
}
}
function cleanLinks() {
document.querySelectorAll('a[href]').forEach(function(a) {
var clean = cleanUrl(a.href);
if (clean !== a.href) a.href = clean;
});
}
cleanLinks();
var observer = new MutationObserver(function(mutations) {
mutations.forEach(function(m) {
m.addedNodes.forEach(function(node) {
if (node.nodeType === 1) {
if (node.tagName === 'A') cleanLinks();
node.querySelectorAll('a[href]').forEach(function(a) {
var clean = cleanUrl(a.href);
if (clean !== a.href) a.href = clean;
});
}
});
});
});
observer.observe(document.body, { childList: true, subtree: true });
})();
}
} catch(__e) { console.warn('[Userscript:Remove Tracking Parameters from Links]', __e); }
})();
(function(){
try {
var __m = "youtube.com";
var __re = new RegExp('^' + "youtube\\.com" + '
[Flight] Fix stack overflow in `visitAsyncNode` with deep async chain… · react/react@cf993fb · GitHub
Skip to content
Commit cf993fb
Browse files
unstubbableunstubbable
authored
[Flight] Fix stack overflow in visitAsyncNode with deep async chains (#35612)
Database libraries like Gel/EdgeDB can create very long linear chains of
async sequences through temporal async sequencing in connection pools.
The recursive traversal of `node.previous` chains in `visitAsyncNode`
causes stack overflow on these deep chains.
The fix converts the `previous` chain traversal from recursive to
iterative. We collect the chain into an array, then process from deepest
to shallowest.
The `awaited` traversal remains recursive since its depth is bounded by
promise dependency depth, not by the number of event loop turns. Each
`awaited` branch still benefits from the iterative `previous` handling
within its own traversal.
I've verified that this fixes the
[repro](https://github.com/jere-co/next-debug) provided in #35246.
closes#35246
1 parent c137dd6 commit cf993fb
2 files changed
Lines changed: 566 additions & 317 deletions
File tree
‎packages/react-server/src/ReactFlightServer.js‎
Lines changed: 47 additions & 29 deletions
Original file line numberDiff line numberDiff line change
@@ -2345,19 +2345,53 @@ function visitAsyncNode(
23452345
>,
23462346
 cutOff: number,
23472347
): void | null | PromiseNode | IONode {
2348-
if(visited.has(node)){
2349-
// It's possible to visit them same node twice when it's part of both an "awaited" path
2350-
// and a "previous" path. This also gracefully handles cycles which would be a bug.
2351-
returnvisited.get(node);
2352-
}
2353-
 // Set it as visited early in case we see ourselves before returning.
2354-
 visited.set(node, null);
2355-
 const result = visitAsyncNodeImpl(request, task, node, visited, cutOff);
2356-
 if (result !== null) {
2357-
// If we ended up with a value, let's use that value for future visits.
2358-
visited.set(node,result);
2348+
// Collect the previous chain iteratively instead of recursively to avoid
2349+
// stack overflow on deep chains. We process from deepest to shallowest so
2350+
// each node has its previousIONode available.
2351+
constchain: Array<AsyncSequence>=[];
2352+
letcurrent: AsyncSequence|null=node;
2353+
2354+
while(current!==null){
2355+
if(visited.has(current)){
2356+
break;
2357+
}
2358+
 chain.push(current);
2359+
 current = current.previous;
23592360
}
2360-
 return result;
2361+
2362+
letpreviousIONode: void|null|PromiseNode|IONode=
2363+
current!==null ? visited.get(current) : null;
2364+
2365+
// Process from deepest to shallowest (reverse order).
2366+
for(leti=chain.length-1;i>=0;i--){
2367+
constn=chain[i];
2368+
// Set it as visited early in case we see the node again before returning.
2369+
visited.set(n,null);
2370+
2371+
constresult=visitAsyncNodeImpl(
2372+
request,
2373+
task,
2374+
n,
2375+
visited,
2376+
cutOff,
2377+
previousIONode,
2378+
);
2379+
2380+
if(result!==null){
2381+
// If we ended up with a value, let's use that value for future visits.
2382+
visited.set(n,result);
2383+
}
2384+
2385+
 if (result === undefined) {
2386+
// Undefined is used as a signal that we found a suitable aborted node
2387+
// and we don't have to find further aborted nodes.
2388+
returnundefined;
2389+
}
2390+
2391+
 previousIONode = result;
2392+
}
2393+
2394+
returnpreviousIONode;
23612395
}
23622396

23632397
functionvisitAsyncNodeImpl(
@@ -2369,6 +2403,7 @@ function visitAsyncNodeImpl(
23692403
void|null|PromiseNode|IONode,
23702404
>,
23712405
 cutOff: number,
2406+
 previousIONode: void | null | PromiseNode | IONode,
23722407
): void | null | PromiseNode | IONode {
23732408
if(node.end>=0&&node.end<=request.timeOrigin){
23742409
// This was already resolved when we started this render. It must have been either something
@@ -2377,23 +2412,6 @@ function visitAsyncNodeImpl(
23772412
returnnull;
23782413
}
23792414

2380-
 let previousIONode: void | null | PromiseNode | IONode = null;
2381-
 // First visit anything that blocked this sequence to start in the first place.
2382-
 if (node.previous !== null) {
2383-
previousIONode=visitAsyncNode(
2384-
request,
2385-
task,
2386-
node.previous,
2387-
visited,
2388-
cutOff,
2389-
);
2390-
if(previousIONode===undefined){
2391-
// Undefined is used as a signal that we found a suitable aborted node and we don't have to find
2392-
// further aborted nodes.
2393-
returnundefined;
2394-
}
2395-
}
2396-
23972415
 // `found` represents the return value of the following switch statement.
23982416
 // We can't use multiple `return` statements in the switch statement
23992417
 // since that prevents Closure compiler from inlining `visitAsyncImpl`
0 commit comments
Comments
 (0)

, 'i');
if (__m === '*' || __re.test(location.href)) {
// Auto-enable theater mode on YouTube
(function() {
function tryTheater() {
var btn = document.querySelector('button[aria-label="Theater mode"], ytd-player #player button[title="Theater mode"]');
if (btn && !btn.classList.contains('activated')) {
btn.click();
}
}
// Try immediately
tryTheater();
// Try after navigation (SPA)
var lastUrl = location.href;
setInterval(function() {
if (location.href !== lastUrl) {
lastUrl = location.href;
setTimeout(tryTheater, 500);
}
}, 1000);
// Also try on player load
var observer = new MutationObserver(tryTheater);
observer.observe(document.body, { childList: true, subtree: true });
})();
}
} catch(__e) { console.warn('[Userscript:YouTube Theater Mode Default]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '
[Flight] Fix stack overflow in `visitAsyncNode` with deep async chain… · react/react@cf993fb · GitHub
Skip to content
Commit cf993fb
Browse files
unstubbableunstubbable
authored
[Flight] Fix stack overflow in visitAsyncNode with deep async chains (#35612)
Database libraries like Gel/EdgeDB can create very long linear chains of
async sequences through temporal async sequencing in connection pools.
The recursive traversal of `node.previous` chains in `visitAsyncNode`
causes stack overflow on these deep chains.
The fix converts the `previous` chain traversal from recursive to
iterative. We collect the chain into an array, then process from deepest
to shallowest.
The `awaited` traversal remains recursive since its depth is bounded by
promise dependency depth, not by the number of event loop turns. Each
`awaited` branch still benefits from the iterative `previous` handling
within its own traversal.
I've verified that this fixes the
[repro](https://github.com/jere-co/next-debug) provided in #35246.
closes#35246
1 parent c137dd6 commit cf993fb
2 files changed
Lines changed: 566 additions & 317 deletions
File tree
‎packages/react-server/src/ReactFlightServer.js‎
Lines changed: 47 additions & 29 deletions
Original file line numberDiff line numberDiff line change
@@ -2345,19 +2345,53 @@ function visitAsyncNode(
23452345
>,
23462346
 cutOff: number,
23472347
): void | null | PromiseNode | IONode {
2348-
if(visited.has(node)){
2349-
// It's possible to visit them same node twice when it's part of both an "awaited" path
2350-
// and a "previous" path. This also gracefully handles cycles which would be a bug.
2351-
returnvisited.get(node);
2352-
}
2353-
 // Set it as visited early in case we see ourselves before returning.
2354-
 visited.set(node, null);
2355-
 const result = visitAsyncNodeImpl(request, task, node, visited, cutOff);
2356-
 if (result !== null) {
2357-
// If we ended up with a value, let's use that value for future visits.
2358-
visited.set(node,result);
2348+
// Collect the previous chain iteratively instead of recursively to avoid
2349+
// stack overflow on deep chains. We process from deepest to shallowest so
2350+
// each node has its previousIONode available.
2351+
constchain: Array<AsyncSequence>=[];
2352+
letcurrent: AsyncSequence|null=node;
2353+
2354+
while(current!==null){
2355+
if(visited.has(current)){
2356+
break;
2357+
}
2358+
 chain.push(current);
2359+
 current = current.previous;
23592360
}
2360-
 return result;
2361+
2362+
letpreviousIONode: void|null|PromiseNode|IONode=
2363+
current!==null ? visited.get(current) : null;
2364+
2365+
// Process from deepest to shallowest (reverse order).
2366+
for(leti=chain.length-1;i>=0;i--){
2367+
constn=chain[i];
2368+
// Set it as visited early in case we see the node again before returning.
2369+
visited.set(n,null);
2370+
2371+
constresult=visitAsyncNodeImpl(
2372+
request,
2373+
task,
2374+
n,
2375+
visited,
2376+
cutOff,
2377+
previousIONode,
2378+
);
2379+
2380+
if(result!==null){
2381+
// If we ended up with a value, let's use that value for future visits.
2382+
visited.set(n,result);
2383+
}
2384+
2385+
 if (result === undefined) {
2386+
// Undefined is used as a signal that we found a suitable aborted node
2387+
// and we don't have to find further aborted nodes.
2388+
returnundefined;
2389+
}
2390+
2391+
 previousIONode = result;
2392+
}
2393+
2394+
returnpreviousIONode;
23612395
}
23622396

23632397
functionvisitAsyncNodeImpl(
@@ -2369,6 +2403,7 @@ function visitAsyncNodeImpl(
23692403
void|null|PromiseNode|IONode,
23702404
>,
23712405
 cutOff: number,
2406+
 previousIONode: void | null | PromiseNode | IONode,
23722407
): void | null | PromiseNode | IONode {
23732408
if(node.end>=0&&node.end<=request.timeOrigin){
23742409
// This was already resolved when we started this render. It must have been either something
@@ -2377,23 +2412,6 @@ function visitAsyncNodeImpl(
23772412
returnnull;
23782413
}
23792414

2380-
 let previousIONode: void | null | PromiseNode | IONode = null;
2381-
 // First visit anything that blocked this sequence to start in the first place.
2382-
 if (node.previous !== null) {
2383-
previousIONode=visitAsyncNode(
2384-
request,
2385-
task,
2386-
node.previous,
2387-
visited,
2388-
cutOff,
2389-
);
2390-
if(previousIONode===undefined){
2391-
// Undefined is used as a signal that we found a suitable aborted node and we don't have to find
2392-
// further aborted nodes.
2393-
returnundefined;
2394-
}
2395-
}
2396-
23972415
 // `found` represents the return value of the following switch statement.
23982416
 // We can't use multiple `return` statements in the switch statement
23992417
 // since that prevents Closure compiler from inlining `visitAsyncImpl`
0 commit comments
Comments
 (0)

, 'i');
if (__m === '*' || __re.test(location.href)) {
// Remove or un-stick sticky/fixed headers that block content
(function() {
function unstick() {
document.querySelectorAll('header, nav, [role="banner"], .header, .navbar, .sticky, .fixed-top, [style*="position: fixed"], [style*="position:sticky"]').forEach(function(el) {
if (el.style.position === 'fixed' || el.style.position === 'sticky' || getComputedStyle(el).position === 'fixed' || getComputedStyle(el).position === 'sticky') {
el.style.position = 'static';
el.style.top = 'auto';
el.style.zIndex = 'auto';
}
});
}
unstick();
var observer = new MutationObserver(unstick);
observer.observe(document.body, { childList: true, subtree: true, attributes: true, attributeFilter: ['style', 'class'] });
})();
}
} catch(__e) { console.warn('[Userscript:Kill Sticky Headers]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '
[Flight] Fix stack overflow in `visitAsyncNode` with deep async chain… · react/react@cf993fb · GitHub
Skip to content
Commit cf993fb
Browse files
unstubbableunstubbable
authored
[Flight] Fix stack overflow in visitAsyncNode with deep async chains (#35612)
Database libraries like Gel/EdgeDB can create very long linear chains of
async sequences through temporal async sequencing in connection pools.
The recursive traversal of `node.previous` chains in `visitAsyncNode`
causes stack overflow on these deep chains.
The fix converts the `previous` chain traversal from recursive to
iterative. We collect the chain into an array, then process from deepest
to shallowest.
The `awaited` traversal remains recursive since its depth is bounded by
promise dependency depth, not by the number of event loop turns. Each
`awaited` branch still benefits from the iterative `previous` handling
within its own traversal.
I've verified that this fixes the
[repro](https://github.com/jere-co/next-debug) provided in #35246.
closes#35246
1 parent c137dd6 commit cf993fb
2 files changed
Lines changed: 566 additions & 317 deletions
File tree
‎packages/react-server/src/ReactFlightServer.js‎
Lines changed: 47 additions & 29 deletions
Original file line numberDiff line numberDiff line change
@@ -2345,19 +2345,53 @@ function visitAsyncNode(
23452345
>,
23462346
 cutOff: number,
23472347
): void | null | PromiseNode | IONode {
2348-
if(visited.has(node)){
2349-
// It's possible to visit them same node twice when it's part of both an "awaited" path
2350-
// and a "previous" path. This also gracefully handles cycles which would be a bug.
2351-
returnvisited.get(node);
2352-
}
2353-
 // Set it as visited early in case we see ourselves before returning.
2354-
 visited.set(node, null);
2355-
 const result = visitAsyncNodeImpl(request, task, node, visited, cutOff);
2356-
 if (result !== null) {
2357-
// If we ended up with a value, let's use that value for future visits.
2358-
visited.set(node,result);
2348+
// Collect the previous chain iteratively instead of recursively to avoid
2349+
// stack overflow on deep chains. We process from deepest to shallowest so
2350+
// each node has its previousIONode available.
2351+
constchain: Array<AsyncSequence>=[];
2352+
letcurrent: AsyncSequence|null=node;
2353+
2354+
while(current!==null){
2355+
if(visited.has(current)){
2356+
break;
2357+
}
2358+
 chain.push(current);
2359+
 current = current.previous;
23592360
}
2360-
 return result;
2361+
2362+
letpreviousIONode: void|null|PromiseNode|IONode=
2363+
current!==null ? visited.get(current) : null;
2364+
2365+
// Process from deepest to shallowest (reverse order).
2366+
for(leti=chain.length-1;i>=0;i--){
2367+
constn=chain[i];
2368+
// Set it as visited early in case we see the node again before returning.
2369+
visited.set(n,null);
2370+
2371+
constresult=visitAsyncNodeImpl(
2372+
request,
2373+
task,
2374+
n,
2375+
visited,
2376+
cutOff,
2377+
previousIONode,
2378+
);
2379+
2380+
if(result!==null){
2381+
// If we ended up with a value, let's use that value for future visits.
2382+
visited.set(n,result);
2383+
}
2384+
2385+
 if (result === undefined) {
2386+
// Undefined is used as a signal that we found a suitable aborted node
2387+
// and we don't have to find further aborted nodes.
2388+
returnundefined;
2389+
}
2390+
2391+
 previousIONode = result;
2392+
}
2393+
2394+
returnpreviousIONode;
23612395
}
23622396

23632397
functionvisitAsyncNodeImpl(
@@ -2369,6 +2403,7 @@ function visitAsyncNodeImpl(
23692403
void|null|PromiseNode|IONode,
23702404
>,
23712405
 cutOff: number,
2406+
 previousIONode: void | null | PromiseNode | IONode,
23722407
): void | null | PromiseNode | IONode {
23732408
if(node.end>=0&&node.end<=request.timeOrigin){
23742409
// This was already resolved when we started this render. It must have been either something
@@ -2377,23 +2412,6 @@ function visitAsyncNodeImpl(
23772412
returnnull;
23782413
}
23792414

2380-
 let previousIONode: void | null | PromiseNode | IONode = null;
2381-
 // First visit anything that blocked this sequence to start in the first place.
2382-
 if (node.previous !== null) {
2383-
previousIONode=visitAsyncNode(
2384-
request,
2385-
task,
2386-
node.previous,
2387-
visited,
2388-
cutOff,
2389-
);
2390-
if(previousIONode===undefined){
2391-
// Undefined is used as a signal that we found a suitable aborted node and we don't have to find
2392-
// further aborted nodes.
2393-
returnundefined;
2394-
}
2395-
}
2396-
23972415
 // `found` represents the return value of the following switch statement.
23982416
 // We can't use multiple `return` statements in the switch statement
23992417
 // since that prevents Closure compiler from inlining `visitAsyncImpl`
0 commit comments
Comments
 (0)

, 'i');
if (__m === '*' || __re.test(location.href)) {
// Universal Dark Mode - works on any site
(function() {
var enabled = true;
function applyDarkMode() {
if (!enabled) return;
// Create style element if it doesn't exist
var style = document.getElementById('universal-dark-mode-style');
if (!style) {
style = document.createElement('style');
style.id = 'universal-dark-mode-style';
document.head.appendChild(style);
}
// Dark mode CSS - inverts colors but preserves images/video
style.textContent = '
/* Invert everything except media */
html {
filter: invert(1) hue-rotate(180deg) !important;
background: #1a1a2e !important;
}
/* Restore images, videos, iframes, canvas */
img, video, iframe, canvas, svg, picture, [style*="background-image"] {
filter: invert(1) hue-rotate(180deg) !important;
}
/* Preserve specific elements that should not be inverted */
.no-dark-mode, .no-dark-mode *,
[data-theme="light"], [data-theme="light"],
.ace_editor, .ace_editor *,
.CodeMirror, .CodeMirror *,
.monaco-editor, .monaco-editor *,
.markdown-body pre, .markdown-body pre *,
.highlight, .highlight *,
pre code, pre code * {
filter: none !important;
}
/* Fix common UI elements */
.modal, .popup, .dropdown-menu, .tooltip, .popover {
filter: invert(1) hue-rotate(180deg) !important;
background: #2d2d44 !important;
border-color: #444 !important;
}
/* Scrollbars */
::-webkit-scrollbar { background: #1a1a2e !important; }
::-webkit-scrollbar-thumb { background: #444 !important; }
::-webkit-scrollbar-thumb:hover { background: #555 !important; }
/* Selection */
::selection { background: #4ecdc4 !important; color: #1a1a2e !important; }
::-moz-selection { background: #4ecdc4 !important; color: #1a1a2e !important; }
';
}
function removeDarkMode() {
var style = document.getElementById('universal-dark-mode-style');
if (style) style.remove();
}
// Toggle with Alt+Shift+D
document.addEventListener('keydown', function(e) {
if (e.altKey && e.shiftKey && e.key === 'D') {
e.preventDefault();
enabled = !enabled;
if (enabled) {
applyDarkMode();
console.log('[Universal Dark Mode] Enabled');
} else {
removeDarkMode();
console.log('[Universal Dark Mode] Disabled');
}
}
});
// Apply on load
applyDarkMode();
// Re-apply on dynamic content
var observer = new MutationObserver(function(mutations) {
if (enabled && !document.getElementById('universal-dark-mode-style')) {
applyDarkMode();
}
});
observer.observe(document.head, { childList: true });
console.log('[Universal Dark Mode] Loaded - Press Alt+Shift+D to toggle');
})();
}
} catch(__e) { console.warn('[Userscript:Universal Dark Mode]', __e); }
})();
})();
[Flight] Fix stack overflow in `visitAsyncNode` with deep async chain… · react/react@cf993fb · GitHub
Skip to content
Commit cf993fb
Browse files
unstubbableunstubbable
authored
[Flight] Fix stack overflow in visitAsyncNode with deep async chains (#35612)
Database libraries like Gel/EdgeDB can create very long linear chains of
async sequences through temporal async sequencing in connection pools.
The recursive traversal of `node.previous` chains in `visitAsyncNode`
causes stack overflow on these deep chains.
The fix converts the `previous` chain traversal from recursive to
iterative. We collect the chain into an array, then process from deepest
to shallowest.
The `awaited` traversal remains recursive since its depth is bounded by
promise dependency depth, not by the number of event loop turns. Each
`awaited` branch still benefits from the iterative `previous` handling
within its own traversal.
I've verified that this fixes the
[repro](https://github.com/jere-co/next-debug) provided in #35246.
closes#35246
1 parent c137dd6 commit cf993fb
2 files changed
Lines changed: 566 additions & 317 deletions
File tree
‎packages/react-server/src/ReactFlightServer.js‎
Lines changed: 47 additions & 29 deletions
Original file line numberDiff line numberDiff line change
@@ -2345,19 +2345,53 @@ function visitAsyncNode(
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>,
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 cutOff: number,
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): void | null | PromiseNode | IONode {
2348-
if(visited.has(node)){
2349-
// It's possible to visit them same node twice when it's part of both an "awaited" path
2350-
// and a "previous" path. This also gracefully handles cycles which would be a bug.
2351-
returnvisited.get(node);
2352-
}
2353-
 // Set it as visited early in case we see ourselves before returning.
2354-
 visited.set(node, null);
2355-
 const result = visitAsyncNodeImpl(request, task, node, visited, cutOff);
2356-
 if (result !== null) {
2357-
// If we ended up with a value, let's use that value for future visits.
2358-
visited.set(node,result);
2348+
// Collect the previous chain iteratively instead of recursively to avoid
2349+
// stack overflow on deep chains. We process from deepest to shallowest so
2350+
// each node has its previousIONode available.
2351+
constchain: Array<AsyncSequence>=[];
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letcurrent: AsyncSequence|null=node;
2353+
2354+
while(current!==null){
2355+
if(visited.has(current)){
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break;
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}
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 chain.push(current);
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 current = current.previous;
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}
2360-
 return result;
2361+
2362+
letpreviousIONode: void|null|PromiseNode|IONode=
2363+
current!==null ? visited.get(current) : null;
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// Process from deepest to shallowest (reverse order).
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for(leti=chain.length-1;i>=0;i--){
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constn=chain[i];
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// Set it as visited early in case we see the node again before returning.
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visited.set(n,null);
2370+
2371+
constresult=visitAsyncNodeImpl(
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request,
2373+
task,
2374+
n,
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visited,
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cutOff,
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previousIONode,
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);
2379+
2380+
if(result!==null){
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// If we ended up with a value, let's use that value for future visits.
2382+
visited.set(n,result);
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}
2384+
2385+
 if (result === undefined) {
2386+
// Undefined is used as a signal that we found a suitable aborted node
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// and we don't have to find further aborted nodes.
2388+
returnundefined;
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}
2390+
2391+
 previousIONode = result;
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}
2393+
2394+
returnpreviousIONode;
23612395
}
23622396

23632397
functionvisitAsyncNodeImpl(
@@ -2369,6 +2403,7 @@ function visitAsyncNodeImpl(
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void|null|PromiseNode|IONode,
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>,
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 cutOff: number,
2406+
 previousIONode: void | null | PromiseNode | IONode,
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): void | null | PromiseNode | IONode {
23732408
if(node.end>=0&&node.end<=request.timeOrigin){
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// This was already resolved when we started this render. It must have been either something
@@ -2377,23 +2412,6 @@ function visitAsyncNodeImpl(
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returnnull;
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}
23792414

2380-
 let previousIONode: void | null | PromiseNode | IONode = null;
2381-
 // First visit anything that blocked this sequence to start in the first place.
2382-
 if (node.previous !== null) {
2383-
previousIONode=visitAsyncNode(
2384-
request,
2385-
task,
2386-
node.previous,
2387-
visited,
2388-
cutOff,
2389-
);
2390-
if(previousIONode===undefined){
2391-
// Undefined is used as a signal that we found a suitable aborted node and we don't have to find
2392-
// further aborted nodes.
2393-
returnundefined;
2394-
}
2395-
}
2396-
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 // `found` represents the return value of the following switch statement.
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 // We can't use multiple `return` statements in the switch statement
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 // since that prevents Closure compiler from inlining `visitAsyncImpl`
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