#77 segfault with dim() in debug mode (snap/linux)

[Sascha Waidmann]

Stepping code in debug mode crashes basic256 with a SEGFAULT under x64-linux (snap version) as soon as I reach a "DIM var(size of array)"-statement in code, while just running the code works fine. This is reproducible for me, at different locations of the DIM in the code.

Is there a way to circumvent in debug mode? (like jump over DIMs)

[Jim Reneau]

Can you upload a simple demo program that causes the fault. It will make it easier to reproduce.

[Sascha Waidmann]

print "This output is okay!"
dim x(100) # segfault, when I reach this point and klick Step >|
print "This is printed when I run the code, but not when I step across in debug mode."

[Jacob Minsky]

I made a fix for this - it's a race condition which requires a check that a variable has been initialized before adding it to the watch window. This is the patch:

Index: VariableWin.cpp
===================================================================
--- VariableWin.cpp (revision 957)
+++ VariableWin.cpp (working copy)
@@ -218,7 +218,7 @@
                for(int y = 0; y<v->data->arr->ydim;y++) {
                    DataElement *q = v->data->arrayGetData(x,y);
                    DataElement::getError(true);
-                   if (q->type!=T_UNASSIGNED) {
+                   if (q && q->type!=T_UNASSIGNED) {
                        varWinAssign(variables, varnum, level, x, y);
                    }
                }  

[Jim Reneau]

Updated and committed to main # 958.

Thanks for the diff.