Undo with text editor and run script crashes blender #54494

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Rob Hughes · 2018-04-02T18:24:06+02:00

Rob Hughes commented

2018-04-02 18:24:06 +02:00

System Information
5820K GTX 970

Blender Version
Latest daily build

Short description of error
Text editor undo after run script can crash Blender

Crash line of code is in text.c - function txt_do_undo - line 2002
int op = text->undo_buf[text->undo_pos];

Reason looks to be that text->undo pos is negative here.

The test to check for a negative value is not made till later.

Possible code change....

int op;
int prev_flags;
unsigned int linep;
unsigned int uni_char;
unsigned int curln, selln;
unsigned short curc, selc;
unsigned short charp;
char *buf;
	
if (text->undo_pos < 0) {
	return;
}
op = text->undo_buf[text->undo_pos];

Exact steps for others to reproduce the error
Load file - press run script - do undo a couple of times

{F2576462}

**System Information** 5820K GTX 970 **Blender Version** Latest daily build **Short description of error** Text editor undo after run script can crash Blender Crash line of code is in text.c - function txt_do_undo - line 2002 int op = text->undo_buf[text->undo_pos]; Reason looks to be that text->undo pos is negative here. The test to check for a negative value is not made till later. Possible code change.... ``` ``` ``` int op; int prev_flags; unsigned int linep; unsigned int uni_char; unsigned int curln, selln; unsigned short curc, selc; unsigned short charp; char *buf; if (text->undo_pos < 0) { return; } op = text->undo_buf[text->undo_pos]; ``` **Exact steps for others to reproduce the error** Load file - press run script - do undo a couple of times {F2576462}

Rob Hughes commented

2018-04-02 18:24:06 +02:00

Added subscriber: @RevDr

Vuk Gardašević changed title from ~~Undo with text editor and runs cript crashes blender~~ to Undo with text editor and run script crashes blender

2018-04-02 19:40:09 +02:00

Philipp Oeser commented

2018-04-04 14:52:35 +02:00

Added subscriber: @lichtwerk

Philipp Oeser self-assigned this 2018-04-04 14:52:35 +02:00

Philipp Oeser commented

2018-04-04 14:52:35 +02:00

Can confirm this [had to press "Run Script" twice before undo to trigger crash], suggested code change also makes sense at first sight, will doublecheck later...

Rob Hughes commented

2018-04-04 19:01:05 +02:00

Although I am sure the change will fix the crash. What I am unsure of (as I don't really know the code) is if calling the function txt_do_undo with text->undo_pos with a value of -1 is a code design feature of if it indicates something else is not right somewhere else.