Deprecate (and mark for removal) HttpContextExtensionService

[laeubi]

The HttpContextExtensionService is effectively unused in platform and uses the abandoned HttpService it is API.

We therefore should deprecate and remove that so the org.eclipse.equinox.http.registry bundle becomes free from any API and only contains internal implementation what would make us free to change how it works,

[github-actions]

Test Results

     24 files  ±0       24 suites  ±0   11m 8s ⏱️ +29s
2 150 tests ±0  2 105 ✔️ ±0  45 💤 ±0  0 ❌ ±0 
2 194 runs  ±0  2 149 ✔️ ±0  45 💤 ±0  0 ❌ ±0 

Results for commit f354afe. ± Comparison against base commit bf62833.

[vogella]

+1

[tjwatson]

Should check for usage from RAP @mknauer

Note this would also have to remove the extension point:

     <extension-point id="httpcontexts" name="%httpcontextsName" schema="schema/httpcontexts.exsd"/>

I find it odd that we deprecate this one extension point when all other extension points in org.eclipse.equinox.http.registry are also dependent on the old http service.

[laeubi]

I find it odd that we deprecate this one extension point when all other extension points in org.eclipse.equinox.http.registry are also dependent on the old http service.

As long as the extension point do not depend on org.osgi.http package I don't think they depend on http service as the impl can choose any technique (including whiteboard http service)

[HannesWell]

In general I fully support deprecating and eventually removing unused elements especially when they cause problems like o.o.service.http.
Nevertheless in this case I'm not familiar with the class to deprecate, but from looking at it I wonder why the only method of the interface HttpContextExtensionService.getHttpContext() is never called (at least Eclipse does not give me a caller)?

I find it odd that we deprecate this one extension point when all other extension points in org.eclipse.equinox.http.registry are also dependent on the old http service.

As long as the extension point do not depend on org.osgi.http package I don't think they depend on http service as the impl can choose any technique (including whiteboard http service)

The extension point contains

equinox/bundles/org.eclipse.equinox.http.registry/schema/httpcontexts.exsd

Line 69 in a72b8ec

<meta.attribute kind="java" basedOn="org.osgi.service.http.HttpContext"/>

so I would say it depends on org.osgi.service.http.

And to give a broader dependencies overview, in the SimRel only RAP and WST depend on equinox.http.registry:

[laeubi]

but from looking at it I wonder why the only method of the interface HttpContextExtensionService.getHttpContext() is never called (at least Eclipse does not give me a caller)?

That's what I written above:

The HttpContextExtensionService is effectively unused in platform

Regarding

The extension point contains

that's independent from this interface, that is never called and currently exposes API, so when we get rid of it, the whole bundle is only "internal" and we can decide how to probably deprecate the extension point.

[HannesWell]

but from looking at it I wonder why the only method of the interface HttpContextExtensionService.getHttpContext() is never called (at least Eclipse does not give me a caller)?

That's what I written above:

The HttpContextExtensionService is effectively unused in platform

OK, but before deprecating an interface usually all references to it in our code-base should be removed.
@laeubi can you please do the corresponding changes/migrations in this PR so that when the interface is eventually removed nothing else has to be changed.