hash: breaking api change

the hash interfaces returned errors before, but the underlying
implementations picked for the hash package never return errors on calls
to Write.

bubbling the errors in the interface like this leads to a lot of
unnecessary error handling, so it's worth breaking the api contract here
(and we're pre-1.0.0 anyway).

Author: ecordell

component/ensure_component.go

@@ -55,11 +55,7 @@ func (e *EnsureComponentByHash[K, A]) Handle(ctx context.Context) {
 	ownedObjs := e.List(ctx, e.nn.MustValue(ctx))
 
 	newObj := e.newObj(ctx)
-	hash, err := e.Hash(newObj)
-	if err != nil {
-		e.ctrls.RequeueErr(ctx, err)
-		return
-	}
+	hash := e.Hash(newObj)
 	newObj = newObj.WithAnnotations(map[string]string{e.HashAnnotationKey: hash})
 
 	matchingObjs := make([]K, 0)
@@ -78,7 +74,7 @@ func (e *EnsureComponentByHash[K, A]) Handle(ctx context.Context) {
 
 	if len(matchingObjs) == 0 {
 		// apply if no matching KubeObject in cluster
-		_, err = e.applyObject(ctx, newObj)
+		_, err := e.applyObject(ctx, newObj)
 		if err != nil {
 			e.ctrls.RequeueErr(ctx, err)
 			return

hash/hash.go

@@ -13,13 +13,13 @@ import (
 )
 
 type (
-	ObjectHashFunc func(obj any) (string, error)
+	ObjectHashFunc func(obj any) string
 	EqualFunc      func(a, b string) bool
 )
 
 // ObjectHasher hashes and object and can compare hashes for equality
 type ObjectHasher interface {
-	Hash(obj any) (string, error)
+	Hash(obj any) string
 	Equal(a, b string) bool
 }
 
@@ -28,7 +28,7 @@ type hasher struct {
 	EqualFunc
 }
 
-func (h *hasher) Hash(obj interface{}) (string, error) {
+func (h *hasher) Hash(obj interface{}) string {
 	return h.ObjectHashFunc(obj)
 }
 
@@ -54,25 +54,24 @@ func NewObjectHash() ObjectHasher {
 
 // SecureObject canonicalizes the object before hashing with sha512 and then
 // with xxhash
-func SecureObject(obj interface{}) (string, error) {
+func SecureObject(obj interface{}) string {
 	hasher := sha512.New512_256()
 	printer := spew.ConfigState{
 		Indent:         " ",
 		SortKeys:       true,
 		DisableMethods: true,
 		SpewKeys:       true,
 	}
-	_, err := printer.Fprintf(hasher, "%#v", obj)
-	if err != nil {
-		return "", err
-	}
+	// sha512's hasher.Write never returns an error, and Fprintf just passes up
+	// the underlying Write call's error, so we can safely ignore the error here
+	_, _ = printer.Fprintf(hasher, "%#v", obj)
 	// xxhash the sha512 hash to get a shorter value
 	xxhasher := xxhash.New()
-	_, err = xxhasher.Write(hasher.Sum(nil))
-	if err != nil {
-		return "", err
-	}
-	return rand.SafeEncodeString(fmt.Sprint(xxhasher.Sum(nil))), nil
+
+	// xxhash's hasher.Write never returns an error, so we can safely ignore
+	// the error here tpp
+	_, _ = xxhasher.Write(hasher.Sum(nil))
+	return rand.SafeEncodeString(fmt.Sprint(xxhasher.Sum(nil)))
 }
 
 // SecureEqual compares hashes safely
@@ -81,19 +80,19 @@ func SecureEqual(a, b string) bool {
 }
 
 // Object canonicalizes the object before hashing with xxhash
-func Object(obj interface{}) (string, error) {
+func Object(obj interface{}) string {
 	hasher := xxhash.New()
 	printer := spew.ConfigState{
 		Indent:         " ",
 		SortKeys:       true,
 		DisableMethods: true,
 		SpewKeys:       true,
 	}
-	_, err := printer.Fprintf(hasher, "%#v", obj)
-	if err != nil {
-		return "", err
-	}
-	return rand.SafeEncodeString(fmt.Sprint(hasher.Sum(nil))), nil
+
+	// xxhash's hasher.Write never returns an error, and Fprintf just passes up
+	// the underlying Write call's error, so we can safely ignore the error here
+	_, _ = printer.Fprintf(hasher, "%#v", obj)
+	return rand.SafeEncodeString(fmt.Sprint(hasher.Sum(nil)))
 }
 
 // Equal compares hashes safely

hash/hash_test.go

@@ -12,7 +12,7 @@ func ExampleObject() {
 			"some": "data",
 		},
 	}
-	hash, _ := Object(configmap)
+	hash := Object(configmap)
 	fmt.Println(Equal(hash, "n688h54h56ch64bh677h55fh648hddq"))
 	// Output: true
 }
@@ -23,7 +23,7 @@ func ExampleSecureObject() {
 			"some": "data",
 		},
 	}
-	hash, _ := SecureObject(secret)
+	hash := SecureObject(secret)
 	fmt.Println(SecureEqual(hash, "n665hb8h667h68hfbhffh669h54dq"))
 	// Output: true
 }