Recover general chunker panics (#3625)

We have recently seen panics when underlying readers panic (which can happen due to third-party library bugs). I'm not sure why the panics are new - it could be a case of bad luck, but there have also been recent changes to error handling. This is the smallest change that seems to fix a real problem but I'm not sure if it's the best global solution.

pkg/sources/chunker.go

@@ -3,6 +3,7 @@ package sources
 import (
 	"bufio"
 	"errors"
+	"fmt"
 	"io"
 
 	"github.com/trufflesecurity/trufflehog/v3/pkg/context"
@@ -99,6 +100,22 @@ func readInChunks(ctx context.Context, reader io.Reader, config *chunkReaderConf
 	go func() {
 		defer close(chunkResultChan)
 
+		// Defer a panic recovery to handle any panics that occur while reading, which can sometimes unavoidably happen
+		// due to third-party library bugs.
+		defer func() {
+			if r := recover(); r != nil {
+				var panicErr error
+				if e, ok := r.(error); ok {
+					panicErr = e
+				} else {
+					panicErr = fmt.Errorf("panic occurred: %v", r)
+				}
+				chunkResultChan <- ChunkResult{
+					err: fmt.Errorf("panic error: %w", panicErr),
+				}
+			}
+		}()
+
 		for {
 			chunkRes := ChunkResult{}
 			chunkBytes := make([]byte, config.totalSize)

pkg/sources/chunker_test.go

@@ -2,6 +2,7 @@ package sources
 
 import (
 	"bytes"
+	"io"
 	"math/rand"
 	"runtime"
 	"strings"
@@ -10,6 +11,7 @@ import (
 	"time"
 
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 
 	"github.com/trufflesecurity/trufflehog/v3/pkg/context"
 )
@@ -121,6 +123,21 @@ func TestNewChunkedReader(t *testing.T) {
 	}
 }
 
+type panicReader struct{}
+
+var _ io.Reader = (*panicReader)(nil)
+
+func (_ panicReader) Read([]byte) (int, error) {
+	panic("panic for testing")
+}
+
+func TestChunkReader_UnderlyingReaderPanics_DoesNotPanic(t *testing.T) {
+	require.NotPanics(t, func() {
+		for range NewChunkReader()(context.Background(), &panicReader{}) {
+		}
+	})
+}
+
 func BenchmarkChunkReader(b *testing.B) {
 	var bigChunk = make([]byte, 1<<24) // 16MB