[jnigen] Don't break method names

[HosseinYousefi]

Let's say that we have two methods void foo(float a) and void foo(double a). JNIgen generates these as void foo(double a) and void foo1(double a), the user can go ahead and use these methods as intended – using the first one for floats and the second one for doubles.

Now say an update of this code, swaps the order of the methods so now foo needs to be run on doubles and foo1 on floats. There will be no compilation error and the code fails in mysterious ways.

Once #746 lands, we can use the same generated yaml/json to see what the mappings signatures were before the regeneration and warn if the naming changes.

@liamappelbe Something to keep in mind for ffigen as well.

[dcharkes]

An alternative would be to make the generator "remember" the naming choices it made before and bootstrap from that naming choice when generating dependent code or code for updated JARs - making the choice sticky and therefore much less breaking.

We could possibly use the existing "imports" mechanism for this?

[HosseinYousefi]

We could possibly use the existing "imports" mechanism for this?

Yes. That's what I referred to in the description:

Once #746 lands, we can use the same generated yaml/json to see what the mappings signatures were before the regeneration and warn if the naming changes.

s/warn if the/use the same/!

[johnmccutchan]

Once #746 lands, we can use the same generated yaml/json to see what the mappings signatures were before the regeneration and warn if the naming changes.

Warning developers is not an acceptable solution. We cannot break users of generated code just because a method was added to an existing class. Full stop.

It sounds like when we generate the bindings, we need to generate a snapshot (json or whatever) of the mapping and when generating bindings jnigen will open that snapshot and use it ensure stable mappings.

[HosseinYousefi]

Warning developers is not an acceptable solution. We cannot break users of generated code just because a method was added to an existing class. Full stop.

Agreed.