Different number of return values

[fatekiller]

Some time some func panic with err Different number of return values, the mock which panic and whether it will panic is randomly, a plot is that I use a go routine in my business func. Is anyone know what is the cause?

[petergtz]

Hi @fatekiller, thanks for reporting this issue. Could you please provide some example code and the actual output you're getting when running your test, and what you would expect instead?

[fatekiller]

thanks for your reply, I can not share the real code, but the output is, I tried recreate this error, but failed....

panic: Different number of return values [recovered]
        panic: Different number of return values

goroutine 129 [running]:
testing.tRunner.func1(0xc0000ffc00)
        /Users/xxx/go@1.13/libexec/src/testing/testing.go:874 +0x3a3
panic(0x1a48580, 0xc0002f7570)
        /Users/xxx/go@1.13/libexec/src/runtime/panic.go:679 +0x1b2
github.com/petergtz/pegomock/internal/verify.Argument(...)
        /Users/xxx/go@1.13/pkg/mod/github.com/petergtz/pegomock@v2.8.0+incompatible/internal/verify/verify.go:7
github.com/petergtz/pegomock.checkAssignabilityOf(0xc000695650, 0x3, 0x3, 0xc0002c0830, 0x1, 0x1)
        /Users/xxx/go@1.13/pkg/mod/github.com/petergtz/pegomock@v2.8.0+incompatible/dsl.go:491 +0x38c
github.com/petergtz/pegomock.(*ongoingStubbing).ThenReturn(0xc00047b2c0, 0xc000695650, 0x3, 0x3, 0x10)
        /Users/xxxx/go@1.13/pkg/mod/github.com/petergtz/pegomock@v2.8.0+incompatible/dsl.go:485 +0x63

[fatekiller]

when I use pegomock generate XXInterface --output-dir=mock to generate mock file, I always got panic: Loading input failed: extra data in buffer, so I used pegomock generate XXInterface --use-experimental-model-gen -m --output-dir=mock, this information maybe helpful

[fatekiller]

It was caused by multi go routine, the code use a global variable lastInvocation to judge whether the return values of last invocation have same length of the given params in pegomock.When(xx).ThenReturn(xx), the lastInvocation can not be modify safely in concurrent environment.

[petergtz]

Hey @fatekiller, would you be able to reproduce the problem with a simplified version of your code that you can actually share (rename variables, remove unneeded logic etc.)? Otherwise this will be nearly impossible to debug.

[fatekiller]

thanks for you help, I have already solved this problem.

[petergtz]

Glad you could solve it. Is there anything we can improve in the library or in the documentation, so you could have solved your issue more quickly?

[fatekiller]

It would be better if you told users that this tool is not thread safely in the manual

[petergtz]

When you refer to multiple threads, do you mean calling When from different goroutines? That's indeed something one shouldn't be doing and you're right, this is not documented.

Note that your mocks can be invoked from multiple goroutines. In that sense pegomock is thread-safe.

Could you clarify?

[petergtz]

Closing due to inactivity.