Decrement via AddUint64(&x, ^uint64(0))

jorbaum · chombium · commit fbf6da3f2424 · 2025-09-30T15:58:04.000+02:00
This decrements the uint64 var like documentation states it, see https://pkg.go.dev/sync/atomic#AddUint64
diff --git a/src/metricemitter/gauge.go b/src/metricemitter/gauge.go
@@ -48,7 +48,7 @@ func (m *Gauge) Increment(value float64) {
 
 // Decrement decrements the gauge by a specified value.
 func (m *Gauge) Decrement(value float64) {
-	atomic.AddUint64(&m.value, toUint64(-value, 2))
+	atomic.AddUint64(&m.value, ^uint64(toUint64(value, 2)-1))
 }
 
 // GetValue atomically returns the current value of the gauge.

Original file line number	Diff line number	Diff line change
`@@ -48,7 +48,7 @@ func (m *Gauge) Increment(value float64) {`
`48`	`48`
`49`	`49`	`// Decrement decrements the gauge by a specified value.`
`50`	`50`	`func (m *Gauge) Decrement(value float64) {`
`51`		`- atomic.AddUint64(&m.value, toUint64(-value, 2))`
	`51`	`+ atomic.AddUint64(&m.value, ^uint64(toUint64(value, 2)-1))`
`52`	`52`	`}`
`53`	`53`
`54`	`54`	`// GetValue atomically returns the current value of the gauge.`