RFR: 7016187: `javac -h` could generate conflict .h for inner class and class name with '_'

[Archie L. Cobbs]

On Fri, 17 Feb 2023 23:31:55 GMT, Jonathan Gibbons <jjg at openjdk.org> wrote:

>> Consider these two classes:
>> 
>> public class Foo_Bar {
>>     public static native void method();
>> }
>> 
>> 
>> public class Foo {
>>     public static class Bar {
>>         public static native void method();
>>     }
>> }
>> 
>> If you run `javac -h` to generate native header files, classes `Foo_Bar` and `Foo$Bar` will want to generate the same native header file `Foo_Bar.h`.
>> 
>> Currently, javac does not detect this situation, so in effect you get a "last writer wins" situation.
>> 
>> This patch causes compilation to fail instead in this case with an error like this:
>> 
>> Foo.java:2: error: error while writing Bar: native header file collision between Foo_Bar and Foo$Bar (both generate Foo_Bar.h)
>>     public static class Bar {
>>                   ^
>> 1 error
>
> The JBS issue lists _two_ problem cases, of which this PR addresses one.
> 
> You should either fix both, or file a subsidiary issue for the part that is not covered here (if that is still an issue):
> 
>> It also does not handle the fields properly for O_I.class and O$I.class if both have same named fields. The generated field constant names are the same in the jni header file.

@jonathan-gibbons - Are you OK with this patch as it currently stands?

Thanks.

-------------

PR: https://git.openjdk.org/jdk/pull/12602