`.RunOptimize()` is not idempotent

tatyana-322 commented 3 months ago

In the cases below, .RunOptimize() always changes container from runContainer16{iv:interval16} to arrayContainer. If applied again, it will change arrayContainer back to runContainer16{iv:interval16} and so on.

My encoding workflow always calls .RunOptimize() before .MarshalBinary(). .MarshalBinary() result differs for arrayContainer and for runContainer16{iv:interval16}. Therefore, on EACH encoding workflow call, binary result will be different for the same contents in bitmap.

Do you mind to make .RunOptimize() idempotent ?

Case 1 with github.com/RoaringBitmap/roaring/v2 v2.3.1 :

import (
    "testing"

    "github.com/RoaringBitmap/roaring/v2"
    "github.com/stretchr/testify/require"
)

func TestBmap(t *testing.T) {
    a := roaring.NewBitmap()
    a.AddMany([]uint32{1, 2, 3})
    a.RunOptimize()
    b1, err := a.MarshalBinary()
    require.NoError(t, err)
    a.RunOptimize()
    b2, err := a.MarshalBinary()
    require.NoError(t, err)
    require.Equal(t, b1, b2) // <- test failed here
}

Case 2 with github.com/RoaringBitmap/roaring v1.9.4:

import (
    "testing"

    "github.com/RoaringBitmap/roaring"
    "github.com/stretchr/testify/require"
)

func TestBmap(t *testing.T) {
    a := roaring.NewBitmap()
    a.AddMany([]uint32{1, 2, 3})
    a.RunOptimize()
    b1, err := a.MarshalBinary()
    require.NoError(t, err)
    a.RunOptimize()
    b2, err := a.MarshalBinary()
    require.NoError(t, err)
    require.Equal(t, b1, b2) // <- test failed here
}