Build checksums during same_contract

core/dbt/contracts/graph/nodes.py

@@ -625,6 +625,11 @@ class ModelNode(CompiledNode):
         # We don't need to construct the checksum if the model does not
         # have contract enforced, because it won't be used.
         # This needs to be executed after contract config is set
+
+        # Should we make this a no-op, if the checksum already exists?
+        if self.contract.checksum is not None:
+            pass
+
         if self.contract.enforced is True:
             contract_state = ""
             # We need to sort the columns so that order doesn't matter
@@ -649,6 +654,12 @@ class ModelNode(CompiledNode):
             # Now it's enforced. This is a change, but not a breaking change -- same_contract: False
             return False
 
+        if not self.contract.checksum:
+            self.build_contract_checksum()
+
+        if not old.contract.checksum:
+            old.build_contract_checksum()
+
         # Otherwise: The contract was previously enforced, and we need to check for changes.
         # Happy path: The contract is still being enforced, and the checksums are identical.
         if self.contract.enforced is True and self.contract.checksum == old.contract.checksum:

core/dbt/parser/schemas.py

@@ -784,6 +784,8 @@ class ModelPatchParser(NodePatchParser[UnparsedModelUpdate]):
 
                 # Includes alias recomputation
                 self.patch_node_config(versioned_model_node, versioned_model_patch)
+                # Need to reapply this here, in the case that 'contract: {enforced: true}' was during config-setting
+                versioned_model_node.build_contract_checksum()
                 source_file.append_patch(
                     versioned_model_patch.yaml_key, versioned_model_node.unique_id
                 )