Will SSDT publish always fail with "Data Loss May Occur" when table is rebuilt?

Consider the following scenario:

• We have a SSDT database project.

• We add a new column to the middle of a table.

• This forces the database project to rebuild the table in order to deploy the change.

• We publish this SSDT database project with the setting “Block incremental deployment if data loss might occur” enabled.

• Because we have the above setting enabled, and (also, I think) the table is being rebuilt the deployment (correctly) throws an error saying data loss may occur.

My question is this: Can we rely on the fact that whenever the table needs to be rebuilt as part of a SSDT publish this error will be thrown?

Yes, you can rely on that. When you enable the "BlockOnDataLoss" attribute what actually happens is that SSDT adds to the deployment script a check like this one

IF EXISTS(SELECT 1 FROM TableToChange)
BEGIN
     RAISEERROR ...
END

StackExchange Database Administrators Q#91133, answer score: 3