RFR: 8254274: Development to add 'lint' warning for @ValueBased classes

[Srikanth Adayapalam]

On Mon, 26 Oct 2020 16:55:22 GMT, Dan Smith <dlsmith at openjdk.org> wrote:

>> New javac lint mode (-Xlint:synchronize) to warn about client side as well JDK internal attempts to synchronize on instances of value based classes
>
> src/jdk.compiler/share/classes/com/sun/tools/javac/code/Lint.java line 288:
> 
>> 286:          * Warn about synchronization attempts on instances of @ValueBased classes.
>> 287:          */
>> 288:         SYNCHRONIZE("synchronize"),
> 
> Suggest calling this `synchronized`, to match the keyword, or `synchronization`, to make it a noun.

Thanks, I prefer the latter and will opt for it (synchronization)

> src/jdk.compiler/share/classes/com/sun/tools/javac/comp/Attr.java line 2424:
> 
>> 2422:             chk.checkRefTypes(tree.typeargs, typeargtypes);
>> 2423: 
>> 2424:             if (localEnv.info.lint.isEnabled(LintCategory.SYNCHRONIZE)) {
> 
> Looks like you're checking calls to wait/notify? I don't think that's necessary—there will already be a warning at the `synchronized` statement; if that doesn't happen, it's malformed code that will fail at runtime (attempting to wait without owning the lock). In practice, I think we just end up with lots of redundant warnings.

Sounds good. I agree this is redundant and noisy.

> src/jdk.compiler/share/classes/com/sun/tools/javac/resources/javac.properties line 262:
> 
>> 260: 
>> 261: javac.opt.Xlint.desc.preview=\
>> 262:     Warn about use of preview language features
> 
> Old code, I know, but the convention appears to be that these descriptions should end in a period. (Same comment for both `javac.opt.Xlint.desc.varargs` and `javac.opt.Xlint.desc.preview`.)

OK, will do.

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PR: https://git.openjdk.java.net/valhalla/pull/237