RFR: 8332039: Cannot invoke "com.sun.source.util.DocTreePath.getTreePath()" because "path" is null

[Jonathan Gibbons]

On Thu, 23 May 2024 10:39:52 GMT, Hannes Wallnöfer <hannesw at openjdk.org> wrote:

> Please review a patch to fix a NPE thrown when a `@since` tag inherited by a nested class contains a nested inline tag. The solution is to make `CommentHelper.getDocTreePath(DocTree)` able to handle block tags inherited by nested classes.

Marked as reviewed by jjg (Reviewer).

src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/toolkit/util/CommentHelper.java line 517:

> 515:     private DocTreePath getInheritedDocTreePath(DocTree dtree) {
> 516:         Utils utils = configuration.utils;
> 517:         if (element instanceof ExecutableElement ee) {

Technically, it is an official anti-pattern to use `instanceof` on Language Model classes. Yes, it works OK for the JDK implementation of `javax.lang.model`, but it is not necessarily true for all other implementations (with a known instance where it is not the case.)

The recommended solution is to either use visitors or test or switch on the `ElementKind`.

That all being said, I accept this is in JDK code ... and now that we have pattern-switch available ...

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PR Review: https://git.openjdk.org/jdk/pull/19363#pullrequestreview-2089110276
PR Review Comment: https://git.openjdk.org/jdk/pull/19363#discussion_r1621264502