Include the incubating dependency in the published pom as an optional dependency

[trask]

Resolves #7119

The published poms for the related modules, e.g. for io.opentelemetry:opentelemetry-sdk-trace, would now include:

    <dependency>
      <groupId>io.opentelemetry</groupId>
      <artifactId>opentelemetry-api-incubator</artifactId>
      <version>1.48.0-alpha</version>
      <scope>runtime</scope>
      <optional>true</optional>
    </dependency>
  </dependencies>

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 89.85%. Comparing base (56941a5) to head (d1ba7c4).
⚠️ Report is 346 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff            @@
##               main    #7137   +/-   ##
=========================================
  Coverage     89.85%   89.85%           
  Complexity     6610     6610           
=========================================
  Files           740      740           
  Lines         19986    19986           
  Branches       1964     1964           
=========================================
  Hits          17958    17958           
  Misses         1439     1439           
  Partials        589      589           

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[jack-berg]

Nice idea. Found more documentation about this capability here: https://docs.gradle.org/current/userguide/feature_variants.html

Its kind of strange. The syntax for instructing gradle to automatically include the dependencies required by the "incubating" feature would look something like:

 implementation("io.opentelemetry:opentelemetry-sdk-trace")) {
     capabilities {
         requireCapability("io.opentelemetry:opentelemetry-sdk-trace-incubating")
     }
 }

With gradle able to resolve the dependencies of the -incubating feature based on contents from the *.module file (e.g. opentelemetry-sdk-trace-1.47.0.module).

Its not a syntax I expect most gradle users would be familiar with, so I wonder if we would be better off telling users to add the required opentelemetry-api-incubator instead of using the requireCapability syntax.

If we go in this direction, here are some other places we would want this:

• :sdk-extensions:jaeger-remote-sampler
• :exporters:common
• :exporters:otlp:all
• :exporters:sender:jdk
• :exporters:sender:okhttp

Seems like it could get complicated quickly.

I wonder if there's any lightweight way to instruct gradle to include the "optional" metadata in pom.xml without leveraging this gradle feature capability.

<scope>compile</scope>
      <optional>true</optional>

[jack-berg]

See #7157 for a possible alternative

[jkwatson]

what's the status on this, @trask ? Let's get it merged or closed in favor of the other one.

[trask]

closing in favor of the less invasive #7157