Add support for @semanticNonNull

[martinbonnin]

@semanticNonNull is the counterpart of onError.

• onError is aimed to be merged in the spec and allow new services to use true nullability (!) without conflating nulls and errors.
• @semanticNonNull is for the transition. It allows existing services that cannot change fields to non-nullable (!) because that would increase the blast radius of errors for older clients to still signal semantic nullability to newer clients.

See the @semanticNonNull GAP for more details.

[github-actions]

Test Report

Test Results

Java Version	Total	Passed	Failed	Errors	Skipped
Java 11	5890 (+9 🟢)	5834 (+9 🟢)	0 (±0)	0 (±0)	56 (±0)
Java 17	5890 (+9 🟢)	5833 (+9 🟢)	0 (±0)	0 (±0)	57 (±0)
Java 21	5890 (+9 🟢)	5833 (+9 🟢)	0 (±0)	0 (±0)	57 (±0)
Java 25	5890 (+9 🟢)	5833 (+9 🟢)	0 (±0)	0 (±0)	57 (±0)
jcstress	32 (±0)	32 (±0)	0 (±0)	0 (±0)	0 (±0)
Total	23592 (+36 🟢)	23365 (+36 🟢)	0 (±0)	0 (±0)	227 (±0)

Code Coverage (Java 25)

Metric	Covered	Missed	Coverage	vs Master
Lines	29751	3131	90.5%	±0.0%
Branches	8744	1536	85.1%	±0.0%
Methods	7934	1210	86.8%	±0.0%

Changed Class Coverage (4 classes)

Class	Line	Branch	Method
g.Directives	+0.1% 🟢	±0.0%	+3.2% 🟢
g.e.NonNullableFieldValidator	-2.2% 🔴	-15.4% 🔴	±0.0%
g.e.ResultPath	+1.9% 🟢	±0.0%	+6.7% 🟢
g.e.SemanticNonNullFieldWasNullError	+70.0% 🟢	±0.0%	+50.0% 🟢

NonNullableFieldValidator — method details

Method	Line	Branch
checkSemanticNonNull new	100.0%	100.0%
listLevel new	100.0%	75.0%
semanticNonNullLevels new	83.3%	50.0%
addError new	100.0%	100.0%
<clinit> new	100.0%	—

Full HTML report: build artifact jacoco-html-report

Updated: 2026-06-02 16:56:51 UTC