On Wed, 4 Dec 2024 17:11:26 GMT, Maurizio Cimadamore <mcimadam...@openjdk.org>
wrote:
> This PR tightens up the logic by which javac reports lint warnings.
> Currently, lint warnings are typically emitted using the following idiom:
>
>
> if (lint.isEnabled(LintCategory.DIVZERO) {
> log.warning(LintCategory.DIVZERO, pos, Warnings.DIVZERO);
> }
>
> There are some issues with this approach:
>
> * logging a lint warning has to be preceded by the correct `isEnabled` check
> * the check and the `log::warning` call must share the same `LintCategory`
> * the selected warning key in the `Warnings` class must also make sense for
> the selected `LintCategory`
>
> This PR addresses these issues, so that the above code is now written as
> follows:
>
>
> lint.logIfEnabled(pos, LintWarnings.DIVZERO);
>
>
> The new idiom builds on a number of small improvements:
>
> * the lint category is now tracked directly in the `compiler.properties` file;
> * a new `LintWarning` class is added to `JCDiagnostic` to model a warning key
> that is also associated with a speicfic `LintCategory` enum constant;
> * the `CompilerProperties` class has a new group of compiler keys, nested in
> the new `LintWarnings` class. This class defines the `LintWarning` objects
> for all the warning keys in `compiler.properties` that have a lint category
> set
> * A new method `Lint::logIfEnabled(Position, LintWarning)` is added - which
> simplifies the logging of lint warnings in many common cases, by merging the
> `isEnabled` check together with the logging.
>
> As bonus points, the signatures of some methods in `Check` and
> `MandatoryWarningHandler` have been tightened to accept not just a `Warning`,
> but a `LintWarning`. This makes it impossible, for instance, to use
> `Check::warnUnchecked` with a warning that is not a true lint warning.
>
> Many thanks @archiecobbs for the useful discussions!
src/jdk.compiler/share/classes/com/sun/tools/javac/comp/Check.java line 1327:
> 1325: DiagnosticPosition prevLintPos =
> deferredLintHandler.setPos(pos);
> 1326: try {
> 1327: deferredLintHandler.report(_ -> {
Nit: we can remove the lambda braces now. Also in a few other places below.
src/jdk.compiler/share/classes/com/sun/tools/javac/comp/Check.java line 5137:
> 5135: log.warning(
> 5136: TreeInfo.diagnosticPositionFor(svuid, tree),
> 5137: Warnings.ImproperSVUID((Symbol)e));
Shouldn't this be changed to `LintWarnings.ImproperSVUID`? There are several
other similar examples in this class.
src/jdk.compiler/share/classes/com/sun/tools/javac/file/BaseFileManager.java
line 528:
> 526: // Check whether we've already opened this file for output
> 527: if (!outputFilesWritten.add(realPath))
> 528: log.warning(LintWarnings.OutputFileClash(path)); // @@@:
> shouldn't we check for suppression?
Re: "shouldn't we check for suppression?": If `-Xlint:-output-file-clash` is in
effect, then `outputFilesWritten` will be null and you'll never get here.
-------------
PR Review Comment: https://git.openjdk.org/jdk/pull/22553#discussion_r1870023374
PR Review Comment: https://git.openjdk.org/jdk/pull/22553#discussion_r1870030235
PR Review Comment: https://git.openjdk.org/jdk/pull/22553#discussion_r1870034373
