I have an old Delphi application and i want to migrate it to the newest Delphi version. The problem is that the application is huge and migrating whole app at once would be too complex. I wonder what is the best approach to do this... Maybe form by form, placing a form into a dll and then using older forms in the new Delphi app and replacing them one by one (after clients confirm one form is working ok to continue with the next one). Not sure if this would be possible at all...Any other ideas?
CodePudding user response：
I presume that based on your comments you do not have comprehensive test cases. In that case, you are simply in a world of pain, and there is nothing that will truly mitigate that. Without test cases, any approach you take will generate errors and bugs that will take you quite a while to catch them all. Build that into your expectations. In fact, with those as your expectations then you need to schedule a large testing phase and maybe that is a good approach. Upgrade all at once and test over the course of a few months.
You could first identify all 3rd party components that will eventually be needed and upgrade them to the latest version one at a time. That way you can at least identify bugs in a controlled manner per 3rd party component. Again, since you are relying on manual testing, this also will be error prone, but maybe you can focus on areas that use the upgraded component preferentially.
CodePudding user response：
here my advice. Before you start migrate, do a refactoring of your existing source-base. 1.) Remove un-used stuff. 2.) Try to move as much as possible to standard delphi components. 3.) Remove "un-used" units from your uses-statements. 4.) If needed, try to do some layering (App-UI,App-Logik,DB-Layer,Libraries) 5.) Look for 3rd-Party Components/Libraries, which might be not needed anymore in the latest Delphi Version, because the functionallity is now included in Delphi. If you spot such components/libraries, try to encapsulate them.
Now you have a new version of your software (still in the old delphi). Test it as exact as possible (Unit-Tests would be perfect).
If this is done, then you start to migrate to newer Delphi. I recommend to do it in one go (instead of dll and one by one).
CodePudding user response：
I do not think there is enough information presented to give you specific advice.
My answer would be to bring in knowledgeable experts to look at your code, talk to your staff, look over your documentation and tests, and then present you with smart options. This can likely all be done via Zoom/Skype online. If you think about how much money you are going to end up spending on the conversion, and how much money you will spend on fixing problems because you went off in the wrong direction (and how many customers you could lose due to bugs/performance issues) this would be an extremely cheap investment.
There are a number of firms with Delphi experience that could help you. (I do not work for one and this is not an ad.) There are some well-known Delphi consultants that would likely have some free, or small flat-fee type, initial conversation.
If you are using a version before the Unicode switch in Delphi 2009, there are a number of online resources to assist. Delphi Conversion Unicode Issues
If you want some real-time advice and chatting about specific issues, check out a Telegram server dedicated to Delphi programming with nearly 800 members. There are nearly always some Delphi experts online answering questions. https://t.me/delphidevelopers You should be able to get some consultancy contacts from that server.