getting around circular references in Delphi [duplicate]

Question

Is there a way of getting around circular unit references in Delphi?

Maybe a newer version of delphi or some magic hack or something?

My delphi project has 100 000+ lines of code mostly based on singleton classes. I need to refactor this, but that would mean several months of "circular reference" hell :)

Answer 1

I've been maintaining close to a million lines of legacy code for the past 10 years so I understand your pain!

In the code that I maintain, when I've encountered circular uses, I frequently have found that they are caused by constants or type definitions in unit A that are needed by unit B. (Sometimes it's also a small bit of code (or even, global variables) in Unit A that is also needed by unit B.

In this situation (when I'm lucky!) I can carefully extract those parts of the code into a new unit C that contains the constants, type definitions, and shared code. Then units A and B use unit C.

I post the above with some hesitance because I'm not an expert on software design and realize there are many others here who are far more knowledgeable than I am. Hopefully, though, my experience will be of some use to you.

Answer 2

1. It seems, you have quite serious code design issues. Beside many signs of such issues, the one is the unit circular references. But as you said - you cannot refactor all the code.
2. Move all what is possible to IMPLEMENTATION section. They are allowed to have circular references.
3. To simplify task (2), you can use 3d party tools. I would recommend - Peganza Pascal Analyzer (http://www.peganza.com). It will suggest what you can move to the implementation section. As will give you much more hints to improve your code quality.