Request for comment: adding EXPECT statements to model files

[Andrew Helwer]

Hi all,

I've implemented a feature in TLC to accept an EXPECT statement in model files. This lets you assert that a given model file is expected to produce a violation. You can see the PR here; please leave feedback if you have any! https://github.com/tlaplus/tlaplus/pull/1269

Currently all this does is make TLC exit with code 0 if the expected violation is generated. It exits with a nonzero code if a different violation was generated, or if no violation was generated. You can assert one of the following in your model file:

• EXPECT NO_VIOLATION
• EXPECT ASSUMPTION_VIOLATION
• EXPECT DEADLOCK_VIOLATION
• EXPECT SAFETY_VIOLATION
• EXPECT LIVENESS_VIOLATION
• EXPECT ASSERT_VIOLATION

If feedback all seems positive I will write some tests for the feature.

Andrew Helwer