[bug] - Refactor newDiff constructor to avoid double initialization of contentWriter (#2742)

* only create the contentWriter once

* update test

* correclty use mock

* remove deprecated pkg

pkg/gitparse/gitparse.go

@@ -77,11 +77,15 @@ func withCustomContentWriter(cr contentWriter) diffOption {
 // The contentWriter is used to manage the diff's content, allowing for flexible handling of diff data.
 // By default, a buffer is used as the contentWriter, but this can be overridden with a custom contentWriter.
 func newDiff(ctx context.Context, commit *Commit, opts ...diffOption) *Diff {
-	diff := &Diff{Commit: commit, contentWriter: bufferwriter.New(ctx)}
+	diff := &Diff{Commit: commit}
 	for _, opt := range opts {
 		opt(diff)
 	}
 
+	if diff.contentWriter == nil {
+		diff.contentWriter = bufferwriter.New(ctx)
+	}
+
 	return diff
 }
 

pkg/gitparse/gitparse_test.go

@@ -2,10 +2,13 @@ package gitparse
 
 import (
 	"bytes"
+	"io"
 	"strings"
 	"testing"
 	"time"
 
+	"github.com/stretchr/testify/assert"
+
 	"github.com/trufflesecurity/trufflehog/v3/pkg/context"
 	bufferwriter "github.com/trufflesecurity/trufflehog/v3/pkg/writers/buffer_writer"
 	bufferedfilewriter "github.com/trufflesecurity/trufflehog/v3/pkg/writers/buffered_file_writer"
@@ -2346,3 +2349,56 @@ index 2ee133b..12b4843 100644
 +output = json
 +region = us-east-2
 `
+
+type mockContentWriter struct{ counter int }
+
+func newMockContentWriter() *mockContentWriter { return &mockContentWriter{counter: 1} }
+
+func (m *mockContentWriter) ReadCloser() (io.ReadCloser, error) {
+	return io.NopCloser(bytes.NewReader([]byte{})), nil
+}
+
+func (m *mockContentWriter) CloseForWriting() error { return nil }
+
+func (m *mockContentWriter) Len() int { return 0 }
+
+func (m *mockContentWriter) String() (string, error) { return "", nil }
+
+func (m *mockContentWriter) Write(p []byte) (n int, err error) { return len(p), nil }
+
+func TestNewDiffContentWriterCreation(t *testing.T) {
+	testCases := []struct {
+		name          string
+		opts          []diffOption
+		expectedCount int
+	}{
+		{
+			name:          "Without custom contentWriter",
+			expectedCount: 1,
+		},
+		{
+			name:          "With custom contentWriter",
+			opts:          []diffOption{withCustomContentWriter(newMockContentWriter())},
+			expectedCount: 1,
+		},
+	}
+
+	for _, tc := range testCases {
+		tc := tc
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+
+			ctx := context.Background()
+			commit := new(Commit)
+
+			mockWriter := newMockContentWriter()
+			assert.NotNil(t, mockWriter, "Failed to create mockWriter")
+
+			diff := newDiff(ctx, commit, tc.opts...)
+			assert.NotNil(t, diff, "Failed to create diff")
+			assert.NotNil(t, diff.contentWriter, "Failed to create contentWriter")
+
+			assert.Equal(t, tc.expectedCount, mockWriter.counter, "Unexpected number of contentWriter creations")
+		})
+	}
+}