I just sponsored this to xenial and yakkety. If you have a moment please check if the SRU-enabled bug description and test case are good enough.
** Description changed: + [Impact] + + Currently less doesn't work correctly with UTF-8 encoded Japanese + characters, wrapping the lines in an invalid manner, missing or + duplicating them (see original description below for exact error cases). + For locale like these it breaks the general workflow, making the tool + unreliable. + + [Test Case] + + 1. Open xterm. + 2. Set the geometory of xterm to 71x22. + 3. Open the attached lesstest.long_jap.txt with less (maybe you need + environment variable LANG=ja_JP.UTF-8) + 4. Type "j", then you will see "003" at the top and only the first part of + the wrapped line should be shown. + 5. Type "k", then you will see "001", "002" and "003" at the top. + + [Regression Potential] + + Rather low as the fix is present in the beta version of less for over 5 + months already, which seems to be enough time for general audience + testing. But since the width tables are modified potentially this could + lead to other similar breakages related to wide-character handling. + + [Original Description] + When you scroll down text with "j" key and encounter a wrapped line with wide characters (such as UTF8-encoded Japanese characters), "less" seems to show the whole wrapped line at a single "j" key, causing the view scroll down by 2 lines at once. Strangely, if you type "k" to scroll up, it does that by only 1 line. As a result, there is a missing line that should have been shown. Even stranger stuff (i.e., duplicate lines) happens when you type "j" and "k" alternately when a wrapped line with wide characters is at the bottom of the view. - # Steps to reproduce 1. Open xterm. 2. Set the geometory of xterm to 71x22. 3. Open the attached lesstest.long_jap.txt with less (maybe you need - environment variable LANG=ja_JP.UTF-8) + environment variable LANG=ja_JP.UTF-8) 4. Type "j", then you will see "003" at the top, and a long wrapped - line with Japanese characters at the bottom. + line with Japanese characters at the bottom. 5. Type "k", then you will see "001" and "003" at the top. "002" is - missing. + missing. # Expected behavior In step 4, only the first part of the wrapped line should be shown. In step 5, all "001", "002" and "003" should be shown. - # Test Environment - Xubuntu 16.04 (Xenial) beta (in VirtualBox on Xubuntu 14.04) - less: 481-2.1 - xterm: 322-1ubuntu1 - Japanese environment (LANG=ja_JP.UTF-8) - # Note - The same problem happens on xfce4-terminal (0.6.3-2ubuntu1) - lv (4.51-2.3build1) doesn't have such problem. - In "less" in Xubuntu 14.04 (version 458-2), this problem didn't - exist. + exist. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1562308 Title: missing or duplicate lines caused by a wrapped line with wide characters To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/less/+bug/1562308/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
