Missing `JsonFactory` "provides" SPI with JPMS in `jackson-core` module

[rashtao]

SPI does not work in Java projects using JPMS, since module-info.java does not contains any provides directive.

To reproduce, I created a Java project with:

• module-info.java

  module foo {
      requires com.fasterxml.jackson.core;
      uses com.fasterxml.jackson.core.JsonFactory;
  }

• main

  public static void main(String[] args) {
        Optional<JsonFactory> jf = ServiceLoader.load(JsonFactory.class).findFirst();
        System.out.println(jf.isPresent()); // --> false
  }

[cowtowncoder]

Interesting, I thought provides was included as format modules do that.

My main/only concern is that in this case it'd be something like

provides com.fasterxml.jackson.core.JsonFactory with
        com.fasterxml.jackson.core.JsonFactory;

which I am not sure works as expected (JsonFactory is only sub-classed by format module implementations in 2.x, basic JsonFactory implements JSON support)

[cowtowncoder]

@rashtao Would it be possible for you to locally build from 2.18 branch, with modified src/moditect/module-info.java to add "provides" directive, and check if that'd work? I can make PR, change, but woudl need someone to validate proposed fix.

EDIT: looks like there is #1339 already, will follow up on that.

[rashtao]

Hi @cowtowncoder ,
I have manually checked that the changes work when building from 2.18. Thanks!

[cowtowncoder]

Thank you for confirming @rashtao ! I hope to release 2.18.0 by end of week.

[GedMarc]

Unrelated to FasterXML/jackson-databind#4727