What could break when migrating from Adobe ColdFusion to an alternative CFML engine?

Question

We are currently using Adobe ColdFusion 9 for a rather large application. We are thinking about moving to Railo or Blue Dragon.

What problems will we run into?

• Will it require a large amount of refactoring or will most CFML code just work on the new system?
• Do alternative engines provide support for most all official tags, or are they more limited?
• In short, how divergent are these alternatives from the official language?
• Is there anything we can do to make this process less painful (like upgrading to CF11 first or removing/avoiding certain features)?

My question is similar to What Notable Differences are there between Railo, Open Bluedragon, and Adobe Coldfusion?, but while that is concerned with practical differences I'm asking more specifically about practicality of transition/implementation.

Answer 1

It all depends on your code and the specific Adobe ColdFusion functionality that you are using. For the most part each CFML iteration supports the same tags/functionality. Where they deviate from the Adobe product is usually documented and explained. You need to dive into your code base and look specifically at the features you are using and compare those to the CFML engine of your choosing. Or you can just download and spin-up the alternate CFML engine, drop your code base in it and see what breaks.

As an example from Railo - CFML Compatibility

Railo tries to adhere the CFML standard as good as possible, Still there are some differences like missing tags and functions or a slightly different behavior. This page and the ones below should describe the incompatibilities.

And I have to question what you are basing this comment on? "and especially it's very uncertain future with them". You are running ColdFusion 9. Adobe has implemented two major version releases since then (10 and 11) and are currently working on the future release.