Question on -Xlint:processing

[Joe Darcy]

Hello.

Yep, that's a bug; I've filed 6739427 "-Xlint:processing not recognized 
as an option" to track this.  -Xlint:processing should be recognized a 
valid option.

-Joe

Peng Li wrote:
> Hi,
>
> I noticed that the "-Xlint:processing" javac command line option is
> broken in the recent openjdk7.  It was never a officially documented
> feature before, but it has been a working feature in earlier JDKs and
> there are people using it.
>
> I investigated the issue and discovered several relevant facts in
> langtools/src/share/classes/com/sun/tools/javac:
>
> (1) The following code assumes that Xlint:processing *is* a valid Xlint option:
>
>      processing/JavacProcessingEnvironment.java:
>      ...
>      lint = options.lint("processing");
>
> (2) The following code assumes that Xlint:processing is *not* a valid
> Xlint option:
>
>      code/Lint.java:
>      ...
>      public enum LintCategory
>
> (3) In the old openjdk code (20071030 and earlier), all command line
> options starting with "-Xlint:" are recogonized as valid Xlint
> options: even "-Xlint:junkfsdjlmcasl" is OK. The relevant code is in
>
>      main/RecognizedOptions.java:
>      ...
>      new XOption(XLINT_CUSTOM,
> "opt.Xlint.suboptlist") {
>              public boolean matches(String s) {
>                 return s.startsWith("-Xlint:");
>
>      A consequence is that, even though "-Xlint:processing" was not
> enumerated as an valid option in code/Lint.java, it was accepted as a
> valid Xlint option and used in
> processing/JavacProcessingEnvironment.java
>
> (4) In the recent openjdk7 code, there is a change in the way valid
> command line options are recognized:
>
>
>      main/RecognizedOptions.java:
>      ...
>      new XOption(XLINT_CUSTOM,
> "opt.Xlint.suboptlist",
>           Option.ChoiceKind.ANYOF, getXLintChoices()),
>
>    This is apparently an improvement over the old openjdk code because
> "-Xlint:junkfsdjlmcasl" will now be reported as an invalid option.
> However, it also breaks all the software that uses the
> "-Xlint:processing" feature:
>
>     $ javac  -Xlint:processing x.java
>     javac: invalid flag: -Xlint:processing
>     Usage: javac <options> <source files>
>     use -help for a list of possible options
>     $
>
> I hope this issue can be fixed in future openjdk versions.  The most
> important question seems to be whether "-Xlint:processing" should be a
> valid and supported option.  If yes, the problem can be fixed by
> simply adding a line in code/Lint.java to recognize the option.  If
> no, a clear-cut decision needs to be made and the code depending on
> this option (for example, processing/JavacProcessingEnvironment.java)
> should be fixed to avoid confusion for developers and users.
>
> Best regards,
> Peng Li
>