bug#20410: 24.5.50; cursor not updated after yank of non-ASCII string from the clipboard

[YAMAMOTO Mitsuharu]

>>>>> On Fri, 24 Apr 2015 09:58:28 +0300, Eli Zaretskii <eliz@gnu.org> said:

>> > What does "C-x =" report before and after step 5?
>> 
>> It says
>> 
>> Char: C-j (10, #o12, #xa) point=191 of 192 (99%) column=0
>> 
>> So, the cursor is actually moved internally, but display is not
>> updated accordingly.

> You show only one result of "C-x =", so it's hard to interpret it,
> especially since you didn't show what was displayed after the paste.

I thought it was clear from the screenshot attached in the first mail.
The point value in the output of "C-x =" indicates that the cursor is
between the initial message of the *scratch* buffer and the yanked
text.

(length ";; This buffer is for notes you don't want to save, and for Lisp 
evaluation.
;; If you want to create a file, visit that file with C-x C-f,
;; then enter the text in that file's own buffer.
")
=> 190

> Does the cursor move to the correct place if you type C-l or invoke
> redraw-display, after performing the recipe?

The cursor appears.  But the cursor at the old position is not
cleared.  See the attached screenshot.

> In any case, cursor motion and display are unrelated to pasting from
> the clipboard, so I wonder whether you could reproduce this without
> the paste, just by typing that character.  I also wonder what does all
> this have to do with expose events, as mentioned in your original
> report.  Anything that I could reproduce here and debug it would be
> helpful.

I could reproduce it without yank.

1. Create a file named a.el with the following contents:

  (global-set-key "a" (string #x3042))  ; HIRAGANA LETTER A

2. $ emacs -Q -D -l a.el &
3. Type "a" to insert a Japanese character.
4. Type "C-p" to move the cursor upward.

Display is updated correctly until Step 3.  But Step 4 does not change
the display from the previous one.

As for expose events, I suspect the current matrices get corrupted,
because the result of git bisect implies that it has something to do
with adjustment of glyph matrices triggered by font loading.

                                     YAMAMOTO Mitsuharu
                                mituharu@math.s.chiba-u.ac.jp