How to handle side effects?

[tk3369]

For example, I have 3 cells:

x = [1, 2, 3]

s = sum(x)

x[1] = 4

Honestly, I don't know if this should be considered a bug or not. If it changes the second cell to 9 then it would look confusing because it appears before the third cell. But the problem is that if I re-run the second cell then it would display 9 and it's still confusing.

I'm filing this issue just to have a discussion.

[fonsp]

#564 #316