Hi,

Seen with diffutils 'master' branch today:

$ cat foo1.txt
你好
$ cat foo2.txt
早晨, 你好
$ src/diff -y foo1.txt foo2.txt
你好                                                          | 早晨, 你好
$ src/diff -l -y foo1.txt foo2.txt


2023-07-04 18:41           diff -l -y foo1.txt foo2.txt           Page 1


                                                              | , 




























































你好早晨你好

(and the last line is not terminated by a newline).

This is strange, isn't it? 'diff' has separate the ASCII from the
non-ASCII parts of the input. With the attached patch, the output becomes:

$ src/diff -l -y foo1.txt foo2.txt


2023-07-04 18:42           diff -l -y foo1.txt foo2.txt           Page 1


你好                                                          | 早晨, 你好





























































(which is more what I had expected).