RFR 8189749: Devise strategy for making source level checks more uniform

[Jonathan Gibbons]

+1. Very nice.

Nit: I would suggest changing multi-catch statements to the plural form.

tests/MulticatchNotSupported.java:39: error: multi-catch statement is 
not supported in -source 6

-- Jon

On 11/28/2017 06:19 AM, Maurizio Cimadamore wrote:
> Updated webrev here:
>
> http://cr.openjdk.java.net/~mcimadamore/8189749-v2/
>
> I've included a report of the diagnostics that have been tweaked by 
> this webrev here to make sure that singular vs. plural is used 
> effectively:
>
> http://cr.openjdk.java.net/~mcimadamore/8189749-v2/diags.html
>
> Cheers
> Maurizio
>
>
> On 20/10/17 19:07, Maurizio Cimadamore wrote:
>> Hi,
>> this biggie patch allows the treatment of source level checks to be 
>> more uniform. The general problem is explained in details here:
>>
>> https://bugs.openjdk.java.net/browse/JDK-8189749
>>
>> Webrev is here:
>>
>> http://cr.openjdk.java.net/~mcimadamore/8189749/
>>
>> The way I approached this, was to create a first class entity, an 
>> enum called Feature. Each 'feature' has:
>>
>> * a min source level (e.g. what is the min source level required to 
>> compile that feature, meaning that lower levels will result in errors)
>> * a max source level (e.g. what is the max source level required to 
>> compile that feature, meaning that higher levels will result in errors)
>> * an optional resource key
>>
>> The first two properties are obviously used to decided if feature XYZ 
>> can be used given source level N. The last property is used to 
>> automate generation of source check diagnostics. Note that this patch 
>> introduce a _single_ source check diagnostic:
>>
>> # 0: message segment (feature), 1: string (found version), 2: string 
>> (expected version)
>> compiler.misc.feature.not.supported.in.source=\
>>    {0} not supported in -source {1}\n\
>>     (use -source {2} or higher to enable {0})
>>
>> And then there's a bunch of feature fragments, example:
>>
>> compiler.misc.feature.modules=\
>>     modules
>>
>> compiler.misc.feature.diamond.and.anon.class=\
>>     ''<>'' with anonymous inner classes
>>
>> compiler.misc.feature.binary.lit=\
>>     binary literals
>>
>> (and many more :-))
>>
>> Since each feature 'knows' its fragment, it is super easy for the 
>> compiler to generate the source level check diagnostic for any 
>> feature. And, if you need to add a new feature, you just need to add 
>> an enum value, and wired it up with the corresponding resource key - 
>> done :-)
>>
>> Since this change affects the way in which source check diagnostics 
>> are generated, quite a lot of changes were required to adjust 
>> expected output in golden files. Aside from those changes, I also 
>> addressed the following issues:
>>
>> * JavaTokenizer was not using SOURCE_LEVEL flags for its diagnostics, 
>> and it was not using the new diagnostic framework to generate errors, 
>> which made the porting harder - so I've fixed that
>> * CALog in Completeness analyzer required a new override for an 
>> AbstractLog::error variant that was probably forgotten (this was 
>> required otherwise CompletenessAnalyzerTest was failing after the 
>> change above)
>> * Log has a 'feature' so that diagnostics marked with the 
>> SOURCE_LEVEL flag can be reported only once per source. But this 
>> check was only looking at the 'head' of a diagnostic, ignoring all 
>> arguments. Since now all source level check diagnostics share the 
>> same head, I needed to tweak the logic to also compare arguments - or 
>> else, one source level check error being reported would also disable 
>> unrelated source level check diags.
>>
>> Then there were a bunch of mechanical translation, for instance 
>> idioms such as:
>>
>> allowSimplifiedVarargs = source.allowSimplifiedVarargs();
>>
>> Were rewritten as:
>>
>> allowSimplifiedVarargs = source.allowed(Feature.SIMPLIFIED_VARARGS);
>>
>> Also, in JavacParser, this idiom:
>>
>> checkTypeAnnotations();
>>
>> has been replaced with
>>
>> checkSourceLevel(Feature.TYPE_ANNOTATIONS);
>>
>> Where checkSourceLevel is a new general routine that works on any 
>> Feature.
>>
>> Finally, where possible, I also got rid of the various boolean flags 
>> of the kind 'allowPrivateMethodInInterfaces' - if the class already 
>> had a 'source' field, the boolean flag can be omitted, and the check 
>> can be performed on the source object itself.
>>
>> Cheers
>> Maurizio
>>
>>
>>
>