JavaScript heap out of memory.

[steabert]

Do you want to request a feature or report a bug?

bug

What is the current behavior?

When a large buffer is passed to a spy, and a check on the spy fails, jest hangs while trying to print out the failure, and eventually ends with a fatal error (heap out of memory);

sample test

The issue doesn't show when running on repl.it, but it does when I run it from the Linux command line:

node_modules/.bin/jest --runTestsByPath --no-cache test.js

When looking at the debugger, it seems it gets stuck trying to pretty format the buffer.

What is the expected behavior?

Jest prints failure in a way that doesn't cause heap out of memory.

Please provide your exact Jest configuration and mention your Jest, node, yarn/npm version and operating system.

Jest v21.2.1
Node v8.5.0
Yarn v1.0.1
OS: Linux (Debian Jessie)

[thymikee]

I think this is basically the same: #1772
There are plans on replacing diff algorithm with more efficient diff-match-patch.
cc: @pedrottimark who's probably on to it in the (hopefully not so distant) future

[pedrottimark]

Yes, it does sound similar to other issue.

Thanks for link to test case. I might have follow up questions next week.

The change to jest-diff will be diff-match-patch in addition to not instead of diff package, but the specific point of failure is concatenation loop in pretty-format package.

Root of problem is what to display when some tests fail, especially if properties of large object or contents of large buffer are not relevant.

[github-actions]

This issue has been automatically locked since there has not been any recent activity after it was closed. Please open a new issue for related bugs.
Please note this issue tracker is not a help forum. We recommend using StackOverflow or our discord channel for questions.