FOBs, those pesky little files that we all take for granted, import into our databases, and live happily ever after. After you read this post, you’ll handle FOB files very, very carefully.
Why is that? Well, if you haven’t already, then read this post first: From C/AL to executable: how NAV runs your C/AL code
Good, now that we are on the same page, let me explain why you must never, ever, ever trust a FOB file.
If you have followed the posts about how C/AL really executes in NAV, you know that C# and C/AL can sometimes be in a state where C/AL compiles, but C# does not, causing you some headaches during run time.
However, what might not be obvious is that there are situations where C/AL does not compile anymore (typically due to a changed dependency signature, or due to an object that went AWOL) but C# not only compiles, but also happily runs as if nothing is wrong in the first place.
These situations can be confusing, and after having read my original post, my friend Heinz has pointed out to those situations and asked me if I can explain them. So, here it goes.