Current version(8.0.7) make Out Of Memory

node.js version: 10.16.0

npm/yarn and version: 1.17.3

@koa/router version: 8.0.7

koa version: 2.11.0

Error message:

<--- Last few GCs --->

[60877:0x102b00000]    35217 ms: Mark-sweep 1387.5 (1416.2) -> 1387.5 (1416.2) MB, 1598.4 / 0.0 ms  (average mu = 0.095, current mu = 0.000) last resort GC in old space requested
[60877:0x102b00000]    36649 ms: Mark-sweep 1387.5 (1416.2) -> 1387.5 (1416.2) MB, 1432.6 / 0.0 ms  (average mu = 0.058, current mu = 0.000) last resort GC in old space requested


<--- JS stacktrace --->

==== JS stack trace =========================================

    0: ExitFrame [pc: 0x3557fc5be3d]
Security context: 0x13a08dc1e6e9 <JSObject>
    1: /* anonymous */ [0x13a0aa29e261] [/Users/user/Documents/workspace/my-project/@koa/router/lib/router.js:~246] [pc=0x3558022e30f](this=0x13a0c2a0be31 <Router map = 0x13a0a2f5da09>)
    2: arguments adaptor frame: 25->0
    3: /* anonymous */(aka /* anonymous */) [0x13a0c24028d9] [0x13a0d3c026f1 <undefined>:30] [bytecode=0x13a00c60dcd...

FATAL ERROR: CALL_AND_RETRY_LAST Allocation failed - JavaScript heap out of memory
 1: 0x10003cf99 node::Abort() [/Users/user/.nvm/versions/node/v10.16.0/bin/node]
 2: 0x10003d1a3 node::OnFatalError(char const*, char const*) [/Users/user/.nvm/versions/node/v10.16.0/bin/node]
 3: 0x1001b7835 v8::internal::V8::FatalProcessOutOfMemory(v8::internal::Isolate*, char const*, bool) [/Users/user/.nvm/versions/node/v10.16.0/bin/node]
 4: 0x100585682 v8::internal::Heap::FatalProcessOutOfMemory(char const*) [/Users/user/.nvm/versions/node/v10.16.0/bin/node]
 5: 0x10058eb84 v8::internal::Heap::AllocateRawWithRetryOrFail(int, v8::internal::AllocationSpace, v8::internal::AllocationAlignment) [/Users/user/.nvm/versions/node/v10.16.0/bin/node]
 6: 0x10055de86 v8::internal::Factory::NewFixedArrayWithFiller(v8::internal::Heap::RootListIndex, int, v8::internal::Object*, v8::internal::PretenureFlag) [/Users/user/.nvm/versions/node/v10.16.0/bin/node]
 7: 0x1005052ae v8::internal::(anonymous namespace)::ElementsAccessorBase<v8::internal::(anonymous namespace)::FastPackedObjectElementsAccessor, v8::internal::(anonymous namespace)::ElementsKindTraits<(v8::internal::ElementsKind)2> >::GrowCapacity(v8::internal::Handle<v8::internal::JSObject>, unsigned int) [/Users/user/.nvm/versions/node/v10.16.0/bin/node]
 8: 0x1007a06bf v8::internal::Runtime_GrowArrayElements(int, v8::internal::Object**, v8::internal::Isolate*) [/Users/donghyun/.nvm/versions/node/v10.16.0/bin/node]
 9: 0x3557fc5be3d
10: 0x3558022e30f

Expected reason:

I tried to find the reason from the recent changes in PR(#50). I found some codes that expected bugs.

https://github.com/koajs/router/commit/e07397c43802c6c9b2064dd4994944b738cb3984#diff-504fd89f344be1e9c4b583f3ebd7428aL262

In this refactoring, there are three i are declared and effected themself. I think it occurs infinite loop.

https://github.com/koajs/router/commit/e07397c43802c6c9b2064dd4994944b738cb3984#diff-504fd89f344be1e9c4b583f3ebd7428aR283

Before refactoring, In this section(this[index] = cloneLayer) refered to index. But after refatoring it chaged like cloneRouter.stack[i] = cloneLayer.

I wonder where the index has been referenced and why I changed it to i.

cc. @JacobMGEvans

[JacobMGEvans]

@egaoneko hahaha I can’t believe I missed that nested for loop nice catch and fix! 🎉

I’ll see if I can write a test for this particular section of code. Thanks for fixing my mistake 😄

[egaoneko]

@JacobMGEvans Oh, I miss watched about index with forEach. When I tested it, It does not occured with just koa and router. We use koa with Next.js, TypeScript, Webpack. I try to make a sample code for it.