RFR: 8334161: Enable -Werror for javac tasks to fail on any warnings

[Kevin Rushforth]

On Tue, 25 Jun 2024 15:48:46 GMT, Andy Goryachev <angorya at openjdk.org> wrote:

>> This PR is a follow-on to #1474.
>> 
>> Enable `javac -Werror` so that javac warnings, including but not limited to javac lint warnings, will cause the build to fail. As with the fix for [JDK-8327255](https://bugs.openjdk.org/browse/JDK-8327255), we define three new properties to enable `-Werror`, one for each type of java compilation task: sdk classes, test classes (including shims), and tool classes (including JSLC). The defaults for `-Werror` for these three groups are:
>> 
>> * `JAVAC_WERROR` : `true`
>> * `TOOL_JAVAC_WERROR` : `false`
>> * `TEST_JAVAC_WERROR` : `false`
>> 
>> They can be overridden on the command line.
>> 
>> I had to do the following two things for the build to pass:
>> 
>> 1. Disable `-Werror` for the `javafx.graphics` module until [JDK-8334137](https://bugs.openjdk.org/browse/JDK-8334137) is fixed. The warning generated when using `sun.misc.Unsafe` in JDK 22 or later cannot be suppressed, so we must not use `-Werror` when compiling the graphics module.
>> 2. Define module-specific `extraLintOptions` in the swing module to disable the "options" lint warning, which is enabled by default. That warning is generated because we (necessarily) use `--source 21` instead of `--release 21` for the Swing module, and don't set the location of the system modules.
>> 
>> I tested this, both locally and via GHA, in the following two branches, each of which introduces an error, the first tests that a removal warning will fail the build and the second tests that a missing explicit constructor will fail the build:
>> 
>> * [test-Werror-removal](https://github.com/kevinrushforth/jfx/tree/test-Werror-removal) : [GHA workflow](https://github.com/kevinrushforth/jfx/actions/runs/9664971290)
>> * [test-Werror-implicit-ctor](https://github.com/kevinrushforth/jfx/tree/test-Werror-implicit-ctor) : [GHA workflow](https://github.com/kevinrushforth/jfx/actions/runs/9664924813)
>
> build.gradle line 2270:
> 
>> 2268:     project.ext.moduleName = "javafx.graphics"
>> 2269: 
>> 2270:     // FIXME: Remove this setting when JDK-8334137 is fixed
> 
> perhaps refer to https://bugs.openjdk.org/browse/JDK-8334161 as well here?

Probably not in this case. We generally don't refer to the bug ID that added a line of code or a comment.

I will add a comment to [JDK-8334137](https://bugs.openjdk.org/browse/JDK-8334137) with a note to remove this block as part of fixing it.

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

PR Review Comment: https://git.openjdk.org/jfx/pull/1475#discussion_r1653341227