This repo is used to reproduce a memory leak in Jest that was introduced between v22.2.2 and v22.3.0.
The test case inside __tests__ will require a very large JavaScript file which will only work when babel transpiling is turned off for this file (in this case, the JavaScript file is an auto-generated asm.js file from the latest PSPDFKit version).
You can see that the transformIgnorePatterns rule proplery works by running:
yarn jest
The leak occurs when using the --coverage option. It seems like the transformIgnorePatterns property is ignored in this case.
yarn jest --coverage
The resulting output will look like this:
<--- Last few GCs --->
[20556:0x102801e00] 17087 ms: Mark-sweep 1407.2 (1467.9) -> 1407.1 (1471.4) MB, 954.8 / 0.0 ms allocation failure GC in old space requested
[20556:0x102801e00] 18088 ms: Mark-sweep 1407.1 (1471.4) -> 1407.0 (1440.4) MB, 1000.9 / 0.0 ms last resort GC in old space requested
[20556:0x102801e00] 19084 ms: Mark-sweep 1407.0 (1440.4) -> 1407.0 (1440.4) MB, 996.6 / 0.0 ms last resort GC in old space requested
<--- JS stacktrace --->
==== JS stack trace =========================================
Security context: 0x2de3696a5501 <JSObject>
1: /* anonymous */ [/Users/philipp/dev/playground/jest-leak/node_modules/babylon/lib/index.js:~3555] [pc=0x1e01706df560](this=0x2de3f97b8849 <Parser map = 0x2de300c69719>,close=0x2de354570589 <TokenType map = 0x2de300c29f51>,possibleAsyncArrow=0x2de3212023e1 <false>)
2: /* anonymous */ [/Users/philipp/dev/playground/jest-leak/node_modules/babylon/lib/index.js:~3507] [pc=0x1e01706cdd08](t...
FATAL ERROR: CALL_AND_RETRY_LAST Allocation failed - JavaScript heap out of memory
1: node::Abort() [/Users/philipp/.asdf/installs/nodejs/9.7.1/bin/node]
2: node::FatalTryCatch::~FatalTryCatch() [/Users/philipp/.asdf/installs/nodejs/9.7.1/bin/node]
3: v8::internal::V8::FatalProcessOutOfMemory(char const*, bool) [/Users/philipp/.asdf/installs/nodejs/9.7.1/bin/node]
4: v8::internal::Factory::NewUninitializedFixedArray(int) [/Users/philipp/.asdf/installs/nodejs/9.7.1/bin/node]
5: 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/philipp/.asdf/installs/nodejs/9.7.1/bin/node]
6: v8::internal::Runtime_GrowArrayElements(int, v8::internal::Object**, v8::internal::Isolate*) [/Users/philipp/.asdf/installs/nodejs/9.7.1/bin/node]
7: 0x1e01705842fd
error Command failed with signal "SIGABRT".
You can see that the stack trace is referencing babylon which should not be running for the large JavaScript file.