I get a data race at internalLoadPredictSizePerValue

[egor-ryashin]

when I call this v, err := jsonvalue.Unmarshal(serialized)

[Andrew-M-C]

Is there any source code to reproduce this bug? And what is your OS env? I think it may indeed be a problem in 32-bit machines.

[Andrew-M-C]

If you are using 32-bit system, you can degraded to v1.3.3. I will fix it ASAP

[egor-ryashin]

64-bit root:xnu-8796.121.3~7/RELEASE_ARM64_T6000 arm64
I think go test -race with the mentioned v, err := jsonvalue.Unmarshal(serialized) should catch it. I see the warning during CI tests.

[Andrew-M-C]

ARM64 MacBook? I borrowed one (Apple M1 Pro) and ran go test -v -race, not errors shown.

I reviewed the codes by myself, there IS a race problem for 32-bit system. I should fix it and release a new one soon.

But for arm64? I think the direct access to an uint64 variable should be goroutine safe. What do you think? Am I wrong?

[Andrew-M-C]

no matter how, I will release a new tag to solve this protencial race problem. If you are in hurry, please downgrade to v1.3.3.

[Andrew-M-C]

Or you may try my latest feature/v1.3.5 branch

[egor-ryashin]

But for arm64? I think the direct access to an uint64 variable should be goroutine safe. What do you think? Am I wrong?

I speculate, it can be atomic but it's not guaranteed. Depends on how a particular compiler and compiler configuration decided to produce a target instruction.

[Andrew-M-C]

Please try feature/v1.3.5, I had removed the "predit" codes. They are not as effecient as I thought.

[egor-ryashin]

Yes, that solved it, thanks. I use this code to reproduce (with go run -test main.go):

package main

import (
	"fmt"
	"github.com/Andrew-M-C/go.jsonvalue"
	"sync"
)

func main() {
	limit := 10
	var wg sync.WaitGroup
	wg.Add(5)
	for i := 0; i < 5; i++ {
		go func(j int) {
			for j := 0; j < 100; j++ {
				v, err := jsonvalue.Unmarshal([]byte(fmt.Sprintf(`
	{
	   "class":"CONSTANT",
	   "type":"VALUE_CONSTANT",
	   "alias":"",
	   "value":{
		  "type":{
			 "id":"INTEGER",
			 "type_info":null
		  },
		  "is_null":false,
		  "value":%d
	   }
	}
`, limit)))
				if err != nil {
					panic(err)
				}
				v.Append(nil)

			}
			wg.Done()
		}(i)
	}
	wg.Wait()
}

for example:

go get "github.com/Andrew-M-C/go.jsonvalue@e60bf16"
go: downloading github.com/Andrew-M-C/go.jsonvalue v1.3.5-0.20230811042225-e60bf16ecdf7
go: upgraded github.com/Andrew-M-C/go.jsonvalue v1.3.4 => v1.3.5-0.20230811042225-e60bf16ecdf7
macbook:rill-developer$ go run -race maintest/testrace/main.go
macbook:rill-developer$ go run -race maintest/testrace/main.go
macbook:rill-developer$ go get "github.com/Andrew-M-C/go.jsonvalue@v1.3.4"
go: downgraded github.com/Andrew-M-C/go.jsonvalue v1.3.5-0.20230811042225-e60bf16ecdf7 => v1.3.4
macbook:rill-developer$ go run -race maintest/testrace/main.go
==================
WARNING: DATA RACE
Write at 0x000102f3e398 by goroutine 9:

[Andrew-M-C]

v1.3.5 released and officially fixed.