RFR: JDK-8250768: javac should be adapted to changes in JEP 12 [v12]

[Magnus Ihse Bursie]

On Tue, 8 Dec 2020 19:35:03 GMT, Jan Lahoda <jlahoda at openjdk.org> wrote:

>> This is an update to javac and javadoc, to introduce support for Preview APIs, and generally improve javac and javadoc behavior to more closely adhere to JEP 12.
>> 
>> The notable changes are:
>> 
>>  * adding support for Preview APIs (javac until now supported primarily only preview language features, and APIs associated with preview language features). This includes:
>>      * the @PreviewFeature annotation has boolean attribute "reflective", which should be true for reflective Preview APIs, false otherwise. This replaces the existing "essentialAPI" attribute with roughly inverted meaning.
>>      * the preview warnings for preview APIs are auto-suppressed as described in the JEP 12. E.g. the module that declares the preview API is free to use it without warnings
>>  * improving error/warning messages. Please see [1] for a list of cases/examples.
>>  * class files are only marked as preview if they are using a preview feature. [1] also shows if a class file is marked as preview or not.
>>  * the PreviewFeature annotation has been moved to jdk.internal.javac package (originally was in the jdk.internal package).
>>  * Preview API in JDK's javadoc no longer needs to specify @preview tag in the source files. javadoc will auto-generate a note for @PreviewFeature elements, see e.g. [2] and [3] (non-reflective and reflective API, respectively). A summary of preview elements is also provided [4]. Existing uses of @preview have been updated/removed.
>>  * non-JDK javadoc is also enhanced to auto-generate preview notes for uses of Preview elements, and for declaring elements using preview language features [5].
>>  
>>  Please also see the CSR [6] for more information.
>>  
>>  [1] http://cr.openjdk.java.net/~jlahoda/8250768/JEP12-errors-warnings-v6.html
>>  [2] http://cr.openjdk.java.net/~jlahoda/8250768/jdk.javadoc.00/api/java.base/java/lang/Record.html
>>  [3] http://cr.openjdk.java.net/~jlahoda/8250768/jdk.javadoc.00/api/java.compiler/javax/lang/model/element/RecordComponentElement.html
>>  [4] http://cr.openjdk.java.net/~jlahoda/8250768/jdk.javadoc.00/api/preview-list.html
>>  [5] http://cr.openjdk.java.net/~jlahoda/8250768/test.javadoc.00/
>>  [6] https://bugs.openjdk.java.net/browse/JDK-8250769
>
> Jan Lahoda has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 55 commits:
> 
>  - Merging recent master changes into JDK-8250768
>  - Fixing navigator for the PREVIEW page.
>  - Fixing typo.
>  - Removing obsolette @PreviewFeature.
>  - Merging master into JDK-8250768
>  - Removing unnecessary property keys.
>  - Cleanup - removing unnecessary code.
>  - Merging master into JDK-8250768-dev4
>  - Reflecting review comments.
>  - Removing trailing whitespace.
>  - ... and 45 more: https://git.openjdk.java.net/jdk/compare/044616bd...0c1c4d57

Build changes still good.

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

Marked as reviewed by ihse (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/703