Re: [tlaplus] How to debug unexpected exception when the error call stack is empty?

It sounds like since the call stack is empty the bug is being hit when evaluating either Init or one of your invariants in the initial state(s). You might be able to identify the problem by disabling checking some of your invariants to see if you can get further before something is hit; that will identify the problematic invariant. You can then sort of do a binary search on that invariant by commenting out half of it, re-running the model checker, and seeing whether the error is hit.

On Saturday, March 20, 2021 at 6:57:40 PM UTC-4 myzh...@xxxxxxxxx wrote:

@Calvin Thanks a lot, Calvin! I have not used any symmetry set.
But the discussion you sent gives me some hints.
I will try to replace some strings with model values and see if the problem can be solved.

On Friday, March 19, 2021 at 12:59:45 PM UTC-7 Calvin Loncaric wrote:
Mingyang,

Are you by any chance using symmetry sets to reduce the state space during model checking?

The call-stack-free error report looks similar to one I have encountered while using symmetry sets: https://github.com/tlaplus/tlaplus/issues/506

Although, it is hard for me to tell for sure if the issues are related without more information.

--
Calvin

On Fri, Mar 19, 2021 at 12:44 PM myzh...@xxxxxxxxx <myzh...@xxxxxxxxx> wrote:
Thanks, Markus!

The spec is pretty long (2k pluscal --> 5k tla+) and still under-development (an academic project).
I could post it when it is more mature/ready to publish.

Mingyang

On Friday, March 19, 2021 at 9:01:06 AM UTC-7 Markus Alexander Kuppe wrote:
On 18.03.21 23:55, myzh...@xxxxxxxxx wrote:
> 1) Let's assume I set the breakpoint at Init. If I use "step over", I
> can reach the breakpoint step by step manually.
> However, if I use "continue", the debug process just ends without giving
> me anything.
> Do I miss something here?
>
> 2) Sometimes, when a breakpoint is reached, the trace list only contains
> "internal error" without showing any trace (I can continue to debug
> though).
> Do you know what does "internal error" mean here?

Hi Mingyang,

thanks for your feedback. I described a workaround for the breakpoint
problem in [1]. For the second bug you've encountered, please add the
spec that triggers it to the corresponding Github issue [2].

Markus

[1] https://github.com/lemmy/vscode-tlaplus/issues/3
[2] https://github.com/lemmy/vscode-tlaplus/issues/4

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