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

[Andy Goryachev]

On Wed, 12 Jun 2024 21:57:32 GMT, Kevin Rushforth <kcr 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)

introduced a javadoc problem and the build failed:


error: warnings found and -Werror specified
1 error
1 warning

> Task :javadoc FAILED


one minor comment.

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?

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

Marked as reviewed by angorya (Reviewer).

PR Review: https://git.openjdk.org/jfx/pull/1475#pullrequestreview-2139104423
PR Review Comment: https://git.openjdk.org/jfx/pull/1475#discussion_r1653091031