gitk crashes if the diff contains certain unicode characters

gitk crashes if the diff contains certain unicode characters

[Glax]

Looks like certain characters cause gitk to crash when it tries to
render a diff.


How to repro:

	git init
	echo foo >foo
	git add foo
	git commit -m foo
	# The following assumes bash builtin echo
	echo -e '\u2754' >foo
	gitk

Now `foo` should contain the character U+2754 encoded as utf-8.

If on gitk you click on "Local uncommitted changes", it'll crash with
the following message:

	X Error of failed request:  BadLength (poly request too large or
internal Xlib length error)
	  Major opcode of failed request:  139 (RENDER)
	  Minor opcode of failed request:  20 (RenderAddGlyphs)
	  Serial number of failed request:  4220
	  Current serial number in output stream:  4247


Note that if I now commit, gitk will crash at startup because the diff
with the character are on the last commit (which gitk selects by default)

	git commit -am crash
	gitk # crashes
	gitk HEAD^ # works fine


After that, you can add a couple more commits and gitk works fine,
unless you click on one of the commits whose diff contain the character.
eg:

	echo foo >foo
	git commit -am foo
	echo bar >foo
	git commit -am bar
	gitk


Version / System:

	$ git --version
	git version 2.20.1
	$ lsb_release -d
	Description:    Ubuntu 19.10

Re: gitk crashes if the diff contains certain unicode characters

[Andreas Schwab]

On Apr 19 2020, Glax wrote:

> Now `foo` should contain the character U+2754 encoded as utf-8.
>
> If on gitk you click on "Local uncommitted changes", it'll crash with
> the following message:

Worksforme.  Could be a bug in your tk library.

Andreas.

-- 
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510  2552 DF73 E780 A9DA AEC1
"And now for something completely different."

Re: gitk crashes if the diff contains certain unicode characters

[Danh Doan]

On 2020-04-19 14:15:06+0200, Glax <glax@dragon.best> wrote:
> Looks like certain characters cause gitk to crash when it tries to
> render a diff.
> 
> 
> How to repro:
> 
> 	git init
> 	echo foo >foo
> 	git add foo
> 	git commit -m foo
> 	# The following assumes bash builtin echo
> 	echo -e '\u2754' >foo
> 	gitk
> 
> Now `foo` should contain the character U+2754 encoded as utf-8.
> 
> If on gitk you click on "Local uncommitted changes", it'll crash with
> the following message:
> 
> 	X Error of failed request:  BadLength (poly request too large or
> internal Xlib length error)
> 	  Major opcode of failed request:  139 (RENDER)
> 	  Minor opcode of failed request:  20 (RenderAddGlyphs)
> 	  Serial number of failed request:  4220
> 	  Current serial number in output stream:  4247

U+2754 is *WHITE* QUESTION MARK ORNAMENT
The error message is very familiar to me.

I /think/ it's a bug in libXft, it can't handle colored emoji, yet.

There're similar issue reported to Google Noto Emoji font:
https://github.com/googlefonts/noto-emoji/issues/183


-- 
Danh