The bug

When a function is terminated because the maxCommandChainLength gamerule value is reached no warning is printed to the log. For command blocks a warning is printed.

An error message is needed since terminating a function during its execution will likely cause undefined behavior.

How to reproduce

1. Download the attached file MC-124446 datapack.zip and place it in the datapacks folder of your world
2. Make sure the value for maxCommandChainLength is at least 2

   /gamerule maxCommandChainLength 2
   

3. Use the following command to verify that the function is working

   /function custom:test
   

   → It runs two commands

4. Set the value for maxCommandChainLength to 1

   /gamerule maxCommandChainLength 2
   

5. Run the function again

   /function custom:test
   

   → It runs one command

6. Look at the log
   → No warning was logged