Error: "Commit tree already contains fiber "19587". This is a bug in React DevTools."

[phoenisx]

Describe what you were doing when the bug occurred:

1. I did profiling on a list, that gets updated on each pagination api call.
2. Once the profiling was done, I moved around in the Profiler to view the Flamegraph
3. Moving to second capture, the Profiler crashed.

DevTools version: 4.6.0-6cceaeb67

Component stack: in ec
    in div
    in div
    in div
    in So
    in Unknown
    in n
    in Unknown
    in div
    in div
    in rl
    in Ze
    in fn
    in Ga
    in _s

[bvaughn]

What does this mean?

Moving to second capture, the Profiler crashed.

Can you repro this bug? And if so, could you share steps for repro with us?

[phoenisx]

Sorry for not providing enough details, but even I don't have enough details. This error just popped up when I was profiling my app in React Devtools.

I was profiling a normal (ul) list, and it broke when I clicked next button on DevTools, to see the recorded profile.

About having a repro, I couldn't replicate it myself after that one occurrence, again.

Anyways, my assumption is (it could be wrong), one of the list item in the flame graph is getting duplicated somehow, either due to the app it was profiling or due to something else.

[bvaughn]

Okay. Thanks for clarifying.

[irohitb]

@bvaughn If no-one is working on this, I would like to assign myself to investigate and fix the issue (since multiple people have referenced it). Also, If you assign me, Can you please also help me with where to look?

[bvaughn]

@irohitb If you'd like to dig into this, we'd be happy to have the help. I don't really have the bandwidth to guide you on it though.

Some places you'd want to look at for starters:

• Store
• ProfilerStore
• Profiler/utils

And for a general overview of how DevTools works, you can check out this: https://github.com/facebook/react/blob/master/packages/react-devtools/OVERVIEW.md