Multiple #EnsuresNonNullIf should be ok; but the compiler complains - java-8

Question

The manual of the Checker Framework claims "You can write multiple #EnsuresNonNullIf annotations on a single method", however I observe the following message if I try this:
#EnsuresNonNullIf(expression="getFieldNames()", result=true)
#EnsuresNonNullIf(expression="getFieldName(i)", result=true)
public boolean hasFieldNames() {
return fFieldNames != null;
}
The resulting error message by the Eclipse Java compiler:
Duplicate annotation of non-repeatable type #EnsuresNonNullIf. Only annotation types marked #Repeatable can be used multiple times at one target.
The resulting error message by the MVN javac compiler:
[ERROR] Blabla.java:[?,?] org.checkerframework.checker.nullness.qual.EnsuresNonNullIf is not a repeatable annotation type
I'm annotating 10-year-old code, so I'm hoping some configuration trick can safe the day :-) Without the multiple #EnsuresNonNullIf I'm up for quite a bit of manual code annotation to fix false positives that I'm not interested in...
PS: I tried using both checker-framework-2.8.1 and 2.9.0 with similar results, and always using <maven.compiler.source>1.8</maven.compiler.source>

Answer 1

I found this issue on the Checker Framework issue tracker: https://github.com/typetools/checker-framework/issues/1307
It explains an "enhancement" request for adding #Repeatable to the following CF annotations:
> #DefaultQualifier -- DONE
> #EnsuresKeyFor
> #EnsuresKeyForIf
> #EnsuresLockHeldIf
> #EnsuresLTLengthOf
> #EnsuresLTLengthOfIf
> #EnsuresMinLenIf
> #EnsuresNonNullIf
> #EnsuresQualifier -- DONE
> #EnsuresQualifierIf -- DONE
> #FieldInvariant
> #GuardSatisfied
> #HasSubsequence
> #MethodVal
> #MinLenFieldInvariant
> #RequiresQualifier -- DONE
> #SubstringIndexFor
And the discussion contains a workaround, since EnsuresQualifiersIf is already repeatable:
#EnsuresQualifiersIf({
#EnsuresQualifierIf(result=true, qualifier=NonNull.class, expression="getFoo()"),
#EnsuresQualifierIf(result=false, qualifier=NonNull.class, expression="getBar()")
})
boolean hasFoo();
And in my case that works out to:
#EnsuresQualifiersIf({
#EnsuresQualifierIf(result=true, qualifier=NonNull.class, expression="getFieldNames()"),
#EnsuresQualifierIf(result=true, qualifier=NonNull.class, expression="getFieldName(i)")
})
public boolean hasFieldNames() {
return fFieldNames != null;
}