From 79e17b8790bafd63506b26d2ecd3797d9bf8b537 Mon Sep 17 00:00:00 2001
From: Andrew Gouin <andrew@gouin.io>
Date: Thu, 12 Dec 2024 08:50:59 -0700
Subject: [PATCH] panic for < 0 shred counts

---
 gerasure/gereedsolomon/encoder.go       | 12 +++++++++---
 gerasure/gereedsolomon/reconstructor.go | 10 ++++++++--
 2 files changed, 17 insertions(+), 5 deletions(-)

diff --git a/gerasure/gereedsolomon/encoder.go b/gerasure/gereedsolomon/encoder.go
index cf78cc3..fa98bce 100644
--- a/gerasure/gereedsolomon/encoder.go
+++ b/gerasure/gereedsolomon/encoder.go
@@ -17,10 +17,16 @@ type Encoder struct {
 // The options within the given reedsolomon.Encoder determine the number of shards.
 func NewEncoder(dataShreds, parityShreds int, opts ...reedsolomon.Option) (*Encoder, error) {
 	if dataShreds <= 0 {
-		return nil, fmt.Errorf("data shreds must be > 0")
+		panic(fmt.Errorf(
+			"BUG: attempted to create reed solomon encoder with dataShreds < 0, got %d",
+			dataShreds,
+		))
 	}
 	if parityShreds <= 0 {
-		return nil, fmt.Errorf("parity shreds must be > 0")
+		panic(fmt.Errorf(
+			"BUG: attempted to create reed solomon encoder with parityShreds < 0, got %d",
+			parityShreds,
+		))
 	}
 	rs, err := reedsolomon.New(dataShreds, parityShreds, opts...)
 	if err != nil {
@@ -31,7 +37,7 @@ func NewEncoder(dataShreds, parityShreds int, opts ...reedsolomon.Option) (*Enco
 
 // Encode satisfies [gerasure.Encoder].
 // Callers should assume that the Encoder takes ownership of the given data slice.
-func (e *Encoder) Encode(_ context.Context, data []byte) ([][]byte, error) {
+func (e Encoder) Encode(_ context.Context, data []byte) ([][]byte, error) {
 	// From the original data, produce new subslices for the data shards and parity shards.
 	allShards, err := e.rs.Split(data)
 	if err != nil {
diff --git a/gerasure/gereedsolomon/reconstructor.go b/gerasure/gereedsolomon/reconstructor.go
index 2ea8f82..6d5b696 100644
--- a/gerasure/gereedsolomon/reconstructor.go
+++ b/gerasure/gereedsolomon/reconstructor.go
@@ -30,10 +30,16 @@ type Reconstructor struct {
 // The shardSize and totalDataSize must be discovered out of band;
 func NewReconstructor(dataShards, parityShards, shardSize int, opts ...reedsolomon.Option) (*Reconstructor, error) {
 	if dataShards <= 0 {
-		return nil, fmt.Errorf("data shards must be > 0")
+		panic(fmt.Errorf(
+			"BUG: attempted to create reed solomon encoder with dataShreds < 0, got %d",
+			dataShards,
+		))
 	}
 	if parityShards <= 0 {
-		return nil, fmt.Errorf("parity shards must be > 0")
+		panic(fmt.Errorf(
+			"BUG: attempted to create reed solomon encoder with parityShreds < 0, got %d",
+			parityShards,
+		))
 	}
 	rs, err := reedsolomon.New(dataShards, parityShards, opts...)
 	if err != nil {