RFR: 8316971: Add Lint warning for restricted method calls [v2]

Vicente Romero vromero at openjdk.org
Thu Sep 28 17:31:29 UTC 2023

On Thu, 28 Sep 2023 15:36:30 GMT, Maurizio Cimadamore <mcimadamore at openjdk.org> wrote:

>> This patch adds a new lint warning category, namely `-Xlint:restricted` to enable warnings on restricted method calls.
>> The patch is relatively straightforward: javac marks methods that are marked with the `@Restricted` annotation with a corresponding internal flag. This is done both in `Annotate` when compiling JDK from source, and in `ClassReader` when JDK classfiles are read. When calls to methods marked with the special flag are found, a new warning is issued.
>> While there are some similarities between this new warning and the preview API warnings, the compiler does *not* emit a mandatory note when a compilation unit is found to have one or more restricted method calls. In other words, this is just a plain lint warning.
>> The output from javac looks as follows:
>> Foo.java:6: warning: [restricted] MemorySegment.reinterpret(long) is a restricted method.
>>       Arena.ofAuto().allocate(10).reinterpret(100);
>>                                  ^
>>   (Restricted methods are unsafe, and, if used incorrectly, they might crash the JVM or result in memory corruption)
> Maurizio Cimadamore has updated the pull request incrementally with one additional commit since the last revision:
>   Update warning message

test/langtools/tools/javac/RestrictedMethods.java line 34:

> 32:         }
> 33:     }
> 34: }

shouldn't this test include a case using method references? For example:

    void m(MemorySegment m) {

    <R> void foo(LongFunction<R> f) {}


PR Review Comment: https://git.openjdk.org/jdk/pull/15964#discussion_r1340470730

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