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

[Maurizio Cimadamore]

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
>
>
>