BUG: internal error in GUI debugger

Help!
1

I’m seeing this in both 10.1.5 & 10.1.7 when stepping through code with the GUI debugger. The initial gspy breakpoint is taken OK, but this happens after the first ‘step into’:

[INTERNAL ERROR: Diff:
'.'(_, roots, A),
'.'(A, patterns, _).
*** <->
'.'(_, roots, _).

Different text depending on what I’m debugging, but the overall pattern is the same. it’s coming from unify_term/2 in prolog_clause.pl but as I’m not sure what that is doing I’m not sure what the exact problem is.

The non-GUI debugger (i.e. spy) seems to be OK.

2

If it helps, these two strings look like they are dict keys.

3

Please share the code that triggers that (as well as where to spy and other relevant details).

4

I can’t provide the code but I’ll see if I can come up with a reproducer. It seems to happen when you are calling a predicate that takes a dict as an argument, and on the initial step into the predicate.

5

I burned through some tokens and generated the attached reproducer. I’ve provided the :robot:'s analysis of the issue, I make absolutely no claims about its correctness :grinning_face_with_smiling_eyes: but the code reproduces the bug,

gspy_dict.pl (1.4 KB)