RFR: 8282483: Ensure that Utils.getAllInterfaces returns unique instances [v4]

[Jonathan Gibbons]

On Thu, 3 Mar 2022 13:22:41 GMT, Pavel Rappo <prappo at openjdk.org> wrote:

>> Instances of TypeMirror that are equal (TypeMirror::equals), aren't necessarily the same (Types::isSameType). If care is not taken when putting instances of TypeMirror into a set, that set might end up containing the same instances.
>> 
>> If Utils.getAllInterfaces is called on a type that extends or implements a particular interface multiple times (on different levels of that type's hierarchy), the returned set might contain multiple representations of that interface. For example, I've seen a case where getAllInterfaces that was passed a TypeElement corresponding to java.util.ArrayList returned a set containing 3 instances of TypeMirror corresponding to `java.util.Collection<E>`.
>> 
>> A bit of archaeology. The old standard doclet (removed in JDK-8177511, commit 33ab1995) collected instances of com.sun.javadoc.Type in a TreeMap, keying them by instances of com.sun.tools.javadoc.main.ClassDocImpl (removed in JDK-8215584, commit 151e628) which implemented Comparable. ClassDocImpl.compareTo worked by comparing instances of CollationKey derived from FQNs of types represented by respective instances of ClassDocImpl.
>> 
>> I'm not sure why `TreeMap<ClassDocImpl, Type>` was changed to `LinkedHashSet<TypeMirror>`.
>
> Pavel Rappo has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Revert inadvertently expanded imports

Marked as reviewed by jjg (Reviewer).

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PR: https://git.openjdk.java.net/jdk/pull/7659