diff --git a/diffmatchpatch/diff.go b/diffmatchpatch/diff.go
index 0f0f88f..6c5383e 100644
--- a/diffmatchpatch/diff.go
+++ b/diffmatchpatch/diff.go
@@ -1338,19 +1338,23 @@ func (dmp *DiffMatchPatch) diffLinesToStrings(text1, text2 string) (string, stri
 	// So we'll insert a junk entry to avoid generating a null character.
 	lineArray := []string{""} // e.g. lineArray[4] == 'Hello\n'
 
+	lineHash := make(map[string]int)
 	// Each string has the index of lineArray which it points to
-	strIndexArray1 := dmp.diffLinesToStringsMunge(text1, &lineArray)
-	strIndexArray2 := dmp.diffLinesToStringsMunge(text2, &lineArray)
+	strIndexArray1 := dmp.diffLinesToStringsMunge(text1, &lineArray, lineHash)
+	strIndexArray2 := dmp.diffLinesToStringsMunge(text2, &lineArray, lineHash)
 
 	return intArrayToString(strIndexArray1), intArrayToString(strIndexArray2), lineArray
 }
 
 // diffLinesToStringsMunge splits a text into an array of strings, and reduces the texts to a []string.
-func (dmp *DiffMatchPatch) diffLinesToStringsMunge(text string, lineArray *[]string) []uint32 {
+func (dmp *DiffMatchPatch) diffLinesToStringsMunge(
+	text string,
+	lineArray *[]string,
+	lineHash map[string]int,
+) []uint32 {
 	// Walk the text, pulling out a substring for each line. text.split('\n')
 	// would would temporarily double our memory footprint.
 	// Modifying text would create many large strings to garbage collect.
-	lineHash := map[string]int{} // e.g. lineHash['Hello\n'] == 4
 	lineStart := 0
 	lineEnd := -1
 	strs := []uint32{}
diff --git a/diffmatchpatch/diff_test.go b/diffmatchpatch/diff_test.go
index f8f7982..dbabb2f 100644
--- a/diffmatchpatch/diff_test.go
+++ b/diffmatchpatch/diff_test.go
@@ -306,6 +306,8 @@ func TestDiffLinesToChars(t *testing.T) {
 		{"a", "b", "1", "2", []string{"", "a", "b"}},
 		// Omit final newline.
 		{"alpha\nbeta\nalpha", "", "1,2,3", "", []string{"", "alpha\n", "beta\n", "alpha"}},
+		// Same lines in Text1 and Text2
+		{"abc\ndefg\n12345\n", "abc\ndef\n12345\n678", "1,2,3", "1,4,3,5", []string{"", "abc\n", "defg\n", "12345\n", "def\n", "678"}},
 	} {
 		actualChars1, actualChars2, actualLines := dmp.DiffLinesToChars(tc.Text1, tc.Text2)
 		assertEqual(t, tc.ExpectedChars1, actualChars1, fmt.Sprintf("Test case #%d, %#v", i, tc))