Handling transport requests is part of an ABAP developer’s craft. However, ABAP developers often know only the basics required to move development objects and customizing through the system landscape. That usually suffices until it doesn’t, and a deeper understanding of the underlying system mechanics becomes necessary.
While researching, I came across some interesting information regarding the import process in Learning Unit 5 of the SAP course “Technical Implementation and Operation II of SAP S/4HANA and SAP Business Suite (old)“. Overall, this free course seems to cover a wealth of valuable information, despite the word “old” in its title.
Here are two practical insights regarding the import process:
First, when multiple transport requests are imported simultaneously, they all pass through each phase of the import process together. This means that if a known faulty transport request (one that would trigger an activation error) is in the import queue, you can place a second transport request containing the fix for that error into the same queue. Importing both requests together avoid the issue.
Second, when a development object is modified via an import, the code belonging to objects that use it (consumers) is also regenerated during the import process. For example, consider a change to a method’s signature: any necessary adjustments to the method calls made by consuming objects must be imported either within the same transport request as the signature change or in a separate request that is imported simultaneously. Otherwise, an error will occur.
Conclusion: There is still much to learn about the Change and Transport System (CTS). By the way, there is also gCTS (Git-enabled CTS).