return T from GetOrRegister instead of any

metrics/counter.go

@@ -7,7 +7,7 @@ import (
 // GetOrRegisterCounter returns an existing Counter or constructs and registers
 // a new Counter.
 func GetOrRegisterCounter(name string, r Registry) *Counter {
-	return GetOrRegister(name, NewCounter, r).(*Counter)
+	return GetOrRegister(name, NewCounter, r)
 }
 
 // NewCounter constructs a new Counter.

metrics/counter_float64.go

@@ -8,7 +8,7 @@ import (
 // GetOrRegisterCounterFloat64 returns an existing *CounterFloat64 or constructs and registers
 // a new CounterFloat64.
 func GetOrRegisterCounterFloat64(name string, r Registry) *CounterFloat64 {
-	return GetOrRegister(name, NewCounterFloat64, r).(*CounterFloat64)
+	return GetOrRegister(name, NewCounterFloat64, r)
 }
 
 // NewCounterFloat64 constructs a new CounterFloat64.

metrics/gauge.go

@@ -11,7 +11,7 @@ func (g GaugeSnapshot) Value() int64 { return int64(g) }
 // GetOrRegisterGauge returns an existing Gauge or constructs and registers a
 // new Gauge.
 func GetOrRegisterGauge(name string, r Registry) *Gauge {
-	return GetOrRegister(name, NewGauge, r).(*Gauge)
+	return GetOrRegister(name, NewGauge, r)
 }
 
 // NewGauge constructs a new Gauge.

metrics/gauge_float64.go

@@ -8,7 +8,7 @@ import (
 // GetOrRegisterGaugeFloat64 returns an existing GaugeFloat64 or constructs and registers a
 // new GaugeFloat64.
 func GetOrRegisterGaugeFloat64(name string, r Registry) *GaugeFloat64 {
-	return GetOrRegister(name, NewGaugeFloat64, r).(*GaugeFloat64)
+	return GetOrRegister(name, NewGaugeFloat64, r)
 }
 
 // GaugeFloat64Snapshot is a read-only copy of a GaugeFloat64.

metrics/gauge_info.go

@@ -16,7 +16,7 @@ func (val GaugeInfoValue) String() string {
 // GetOrRegisterGaugeInfo returns an existing GaugeInfo or constructs and registers a
 // new GaugeInfo.
 func GetOrRegisterGaugeInfo(name string, r Registry) *GaugeInfo {
-	return GetOrRegister(name, NewGaugeInfo, r).(*GaugeInfo)
+	return GetOrRegister(name, NewGaugeInfo, r)
 }
 
 // NewGaugeInfo constructs a new GaugeInfo.

metrics/meter.go

@@ -12,7 +12,7 @@ import (
 // Be sure to unregister the meter from the registry once it is of no use to
 // allow for garbage collection.
 func GetOrRegisterMeter(name string, r Registry) *Meter {
-	return GetOrRegister(name, NewMeter, r).(*Meter)
+	return GetOrRegister(name, NewMeter, r)
 }
 
 // NewMeter constructs a new Meter and launches a goroutine.

metrics/registry.go

@@ -327,11 +327,11 @@ func Get(name string) interface{} {
 
 // GetOrRegister gets an existing metric or creates and registers a new one. Threadsafe
 // alternative to calling Get and Register on failure.
-func GetOrRegister[T any](name string, ctor func() T, r Registry) interface{} {
+func GetOrRegister[T any](name string, ctor func() T, r Registry) T {
 	if r == nil {
 		r = DefaultRegistry
 	}
-	return r.GetOrRegister(name, func() any { return ctor() })
+	return r.GetOrRegister(name, func() any { return ctor() }).(T)
 }
 
 // Register the given metric under the given name.  Returns a ErrDuplicateMetric

metrics/registry_test.go

@@ -98,10 +98,10 @@ func TestRegistryGetOrRegister(t *testing.T) {
 	r := NewRegistry()
 
 	// First metric wins with GetOrRegister
-	_ = GetOrRegister("foo", NewCounter, r)
-	m := GetOrRegister("foo", NewGauge, r)
-	if _, ok := m.(*Counter); !ok {
-		t.Fatal(m)
+	c1 := GetOrRegister("foo", NewCounter, r)
+	c2 := GetOrRegister("foo", NewCounter, r)
+	if c1 != c2 {
+		t.Fatal("counters should've matched")
 	}
 
 	i := 0
@@ -123,10 +123,10 @@ func TestRegistryGetOrRegisterWithLazyInstantiation(t *testing.T) {
 	r := NewRegistry()
 
 	// First metric wins with GetOrRegister
-	_ = GetOrRegister("foo", NewCounter, r)
-	m := GetOrRegister("foo", NewGauge, r)
-	if _, ok := m.(*Counter); !ok {
-		t.Fatal(m)
+	c1 := GetOrRegister("foo", NewCounter, r)
+	c2 := GetOrRegister("foo", NewCounter, r)
+	if c1 != c2 {
+		t.Fatal("counters should've matched")
 	}
 
 	i := 0

metrics/resetting_timer.go

@@ -8,7 +8,7 @@ import (
 // GetOrRegisterResettingTimer returns an existing ResettingTimer or constructs and registers a
 // new ResettingTimer.
 func GetOrRegisterResettingTimer(name string, r Registry) *ResettingTimer {
-	return GetOrRegister(name, NewResettingTimer, r).(*ResettingTimer)
+	return GetOrRegister(name, NewResettingTimer, r)
 }
 
 // NewRegisteredResettingTimer constructs and registers a new ResettingTimer.

metrics/timer.go

@@ -10,7 +10,7 @@ import (
 // Be sure to unregister the meter from the registry once it is of no use to
 // allow for garbage collection.
 func GetOrRegisterTimer(name string, r Registry) *Timer {
-	return GetOrRegister(name, NewTimer, r).(*Timer)
+	return GetOrRegister(name, NewTimer, r)
 }
 
 // NewCustomTimer constructs a new Timer from a Histogram and a Meter.