RFR: 8318082: ConcurrentModificationException from IndexWriter

[Jonathan Gibbons]

On Thu, 19 Oct 2023 16:03:37 GMT, Pavel Rappo <prappo at openjdk.org> wrote:

> Please review this fix to a bug in indexing.
> 
> The bug has been dormant for many releases and was noticed only because its likelihood was increased by [JDK-8286470](https://bugs.openjdk.org/browse/JDK-8286470) in JDK 21.
> 
> Here's the bug: every time an item is indexed, it is indexed relative to the context that triggers the indexing. For example, if an item is indexed in the context of a class page, then the index will refer to that class page. However, if that same item is indexed in the context of the "Deprecated" page, then the index will refer to the "Deprecated" page.
> 
> Since an item is indexed every time it is seen, the fix is to never index an item if seen in the context of a _derived_ page, such as hierarchy trees, indexes, and various lists (e.g. deprecated, new, preview). The fix includes a comprehensive test and updates an existing test to correct its bad assumptions.

Approved, but would be nice to eventually replace the use of `instanceof` perhaps by using the proposed ` PageKind` and/or some new method on `HtmlDocletWriter`.

As always, coming up with a decent name (and documentation) for new methods is often the hardest part of a fix.

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Marked as reviewed by jjg (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/16271#pullrequestreview-1688705931