runtime: crash message not included in debug.SetCrashOutput

[dsnet]

Go version

go1.25

Output of go env in your module/workspace:

n/a

What did you do?

Call debug.SetCrashOutput and run a program that deliberately causes a fatal error.

What did you see happen?

I see crash.txt only include a bunch of stack traces.

What did you expect to see?

I expect crash.txt to start with:

fatal error: concurrent map writes

Note that a regular panic that is not recovered includes the panic message in the crash output, so the intent seems to be that the fatal message should be captured.

[gopherbot]

Change https://go.dev/cl/730580 mentions this issue: runtime: include throw and fatal message in SetCrashOutput

[gabyhelp]

Related Issues

• runtime: printing multiple fatal errors may interleave messages #69447 (closed)
• runtime/debug: add SetCrashOutput(file *os.File) #42888 (closed)

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