Whoops, sent the wrong patch; here's the corrected one.

(file #26010)

Thank you very much for the fast response. I was stunned to see this problem not being reported earlier, especially since the last 6 versions have it.

Since version 2.6.1 grep doesn't work correctly if you use a case-insesitive search with UTF8 encoding when there is an UTF8 character. Here is the example:

# Without -i switch everything works correctly
$ echo -e 'AA UTF8 char İ 12345\nAA 12345' | grep 'AA'
AA UTF8 char İ 12345
AA 12345


# With -i it breaks
$ echo -e 'AA UTF8 char İ 12345\nAA 12345' | grep -i 'AA'
AA UTF8 char İ 12345AA 12345


As you can see it somehow deletes the new line character in the line which has an UTF8 'İ' character.

Everything works correctly in versions 2.5.4 and below, it's broken from 2.6.1 to the latest version (which is atm 2.6.12).

This is a big concern, since it can break scripts which filtered UTF8 input using -i switch.