fix: replace panics with proper error returns

account.go

@@ -157,7 +157,7 @@ func (slice AccountMetaSlice) Len() int {
 
 func (slice AccountMetaSlice) SplitFrom(index int) (AccountMetaSlice, AccountMetaSlice) {
 	if index < 0 {
-		panic("negative index")
+		return AccountMetaSlice{}, slice
 	}
 	if index == 0 {
 		return AccountMetaSlice{}, slice

account_test.go

@@ -212,8 +212,9 @@ func TestSplitFrom(t *testing.T) {
 		require.Len(t, part1, 5)
 		require.Len(t, part2, 0)
 	}
-	require.Panics(t,
-		func() {
-			slice.SplitFrom(-1)
-		})
+	{
+		part1, part2 := slice.SplitFrom(-1)
+		require.Len(t, part1, 0)
+		require.Len(t, part2, 5)
+	}
 }

diff/diff.go

@@ -192,21 +192,22 @@ func reflectValueCanIsNil(value reflect.Value) bool {
 	}
 }
 
-func Diff(left any, right any, opts ...Option) {
+func Diff(left any, right any, opts ...Option) error {
 	options := options{}
 	for _, opt := range opts {
 		opt.apply(&options)
 	}
 
 	if options.onEvent == nil {
-		panic("the option diff.OnEvent(...) must always be defined")
+		return fmt.Errorf("the option diff.OnEvent(...) must always be defined")
 	}
 
 	reporter := &diffReporter{notify: options.onEvent}
 	cmp.Equal(left, right, append(
 		[]cmp.Option{cmp.Reporter(reporter)},
 		options.cmpOptions...,
 	)...)
+	return nil
 }
 
 type diffReporter struct {

diff/diff_test.go

@@ -196,14 +196,14 @@ func TestDiff_EventMatch(t *testing.T) {
 // only single event but starts to act weirdly when there > 1, like the Event's Path is all wrong. It's
 // better to try to avoid it when possible.
 func accumulateDiff(left, right any) (out []Event) {
-	Diff(left, right, OnEvent(func(event Event) {
+	_ = Diff(left, right, OnEvent(func(event Event) {
 		out = append(out, event)
 	}))
 	return
 }
 
 func accumulateDiffStrings(left, right any) (out []string) {
-	Diff(left, right, OnEvent(func(event Event) {
+	_ = Diff(left, right, OnEvent(func(event Event) {
 		out = append(out, eventToString(&event))
 	}))
 	return

keys.go

@@ -139,18 +139,22 @@ func (k PrivateKey) Sign(payload []byte) (Signature, error) {
 	return signature, err
 }
 
-func (k PrivateKey) PublicKey() PublicKey {
+func (k PrivateKey) PublicKeyOrErr() (PublicKey, error) {
 	if err := k.Validate(); err != nil {
-		panic(err)
+		return PublicKey{}, err
 	}
 
 	p := voied25519.PrivateKey(k)
 	pub := p.Public().(voied25519.PublicKey)
 
 	var publicKey PublicKey
 	copy(publicKey[:], pub)
+	return publicKey, nil
+}
 
-	return publicKey
+func (k PrivateKey) PublicKey() PublicKey {
+	pub, _ := k.PublicKeyOrErr()
+	return pub
 }
 
 // PK is a convenience alias for PublicKey

transaction.go

@@ -634,7 +634,7 @@ func (tx *Transaction) String() string {
 	buf := new(bytes.Buffer)
 	_, err := tx.EncodeTree(text.NewTreeEncoder(buf, ""))
 	if err != nil {
-		panic(err)
+		return fmt.Sprintf("<transaction encoding error: %s>", err)
 	}
 	return buf.String()
 }