Display bug for editing lines with full-width characters

[Misaki]

I'm not entirely sure this isn't a bug with bash, instead of gnome-terminal.

Full-width character, followed by at least one full word with a space after it.

Example: あa a

With trailing space.

Typing before the full-width character causes the 'あ' to be pushed to next line, with a blank space on previous line though if selected and copied it will actually produce a space.

The 'あ' occupies two columns on the new line, but characters after the first a are only moved one column to the right. The first a, or the first character after the 'あ' including a space, is pushed two columns to the right, covering the second character after the 'あ'.

A similar bug occurs when deleting characters before the 'あ', except no trailing space is required. A character is duplicated but might be first letter of first word on second line, or last letter of next word. Duplicating one letter as soon as 'あ' goes to previous line is easy to replicate; duplicating other letters as further characters before 'あ' are deleted might only happen after resetting the line using up arrow then down arrow, but actually just because of forward bug because displayed characters change after pressing up then down. Second word on line only seems to be affected if no other words after it.

ProblemType: Bug
DistroRelease: Ubuntu 14.10
Package: gnome-terminal 3.6.2-0ubuntu1
ProcVersionSignature: Ubuntu 3.16.0-30.40-generic 3.16.7-ckt3
Uname: Linux 3.16.0-30-generic x86_64
NonfreeKernelModules: nvidia
ApportVersion: 2.14.7-0ubuntu8.2
Architecture: amd64
CurrentDesktop: Unity
Date: Tue Apr 14 02:37:03 2015
SourcePackage: gnome-terminal
UpgradeStatus: No upgrade log present (probably fresh install)

[Misaki (myjunkmail311006)]

The trailing space doesn't show up as excess whitespace is removed on launchpad, however it was necessary to replicate the bug.

[Egmont Koblinger (egmont-gmail)]

As a rule of thumb: try these in xterm (and maybe a few other terminals); if it's the same there then it's probably a bash/readline bug :) as it's also the case in these examples.

The first one is especially tricky: in order for both the display to look good and copy-paste to behave correctly (that is: omit that space, yet not contain an explicit newline), bash has to chop off the end of the first line, and then print the CJK and assume that the terminal will correctly completely wrap it to the second line.

The next two seem to be simpler display bugs in bash/readline.

The best place to report this problem would be the bash mailing list, see http://lists.gnu.org/archive/html/bug-bash/ and the "BUG REPORTS" section of the bash manpage, thanks!