Golang built-in print(ln) function's weird behaviour

Faced some unexpected order of console output using built-in print(ln). Go version is 1.21.3.

The next code:

package main

import (
    "fmt"
)

func main() {
    println("a=1")
    a := 1
    fmt.Println(a)

    println("b=2")
    b := 2
    fmt.Println(b)

    a = b
    b = a
    fmt.Println(a)
    fmt.Println(b)
    println("ab")
}

has the next output on my local machine:

a=1
b=2
ab
1
2
2
2

Taking in account the actual order of calls, the expected output is:

a=1
1
b=2
2
2
2
ab

which satisfies my expectations when I use online Go compilers (including Go Playground).

It is also important that the order of print(ln) output (locally too) may vary extremely rarely but still wrong for the most part.

>Solution :

print writes to stderr, fmt.Print writes to stdout. You are observing two separate streams when you mix print and fmt.Print functions.