Allow applying plugins with matching versions

[octylFractal]

This resolves a long-standing issue with applying a plugin in a
subproject when that same plugin is already applied in the parent project.
Prior to this commit, you would need to avoid specifying a version,
which only became a true hassle with the introduction of plugins in the
version catalog, as shown in #18236.

This commit does not attempt to resolve conflicting versions, or inspect
the classpath for a plugin version. It only records the data that Gradle
knows for sure, and uses that to slightly relax this check. It is
sufficient to allow the issue mentioned prior to be resolved.

Replaces #18728
Fixes #18236

If accepted, I'll do the following:

• Update documention
• Document the feature in release notes

[asodja]

Awesome that you found a way to collect applied plugin versions! I just left a comment regarding having a direct dependency on plugins in ClassLoaderScope.

One question: Could we add also functionality to define "withoutVersion" plugins in the Version catalog?
I think it might come in handy in some cases, e.g. so you can generate type-safe accessors for precompiled scripts, or when the plugin is added to the classpath through methods where we cannot collect versions.

[octylFractal]

Currently failing due to classcycle, see internal Slack. Resolved.

[octylFractal]

@ljacomet @big-guy this is almost ready to go, but do you know if we have anywhere in the documentation that references the restriction on versions that this PR weakens? I didn't see any, so I didn't change the documentation, but maybe it's in an unusual place.

[ljacomet]

One question about the added state and a minor release note comment.

For documentation, have a look at https://docs.gradle.org/current/userguide/plugins.html#sec:subprojects_plugins_dsl. Maybe adding a note there makes sense and linking to that section from https://docs.gradle.org/current/userguide/platforms.html#sec:plugins would improve the situation.

[ljacomet]

LGTM!

[octylFractal]

@asodja re:

One question: Could we add also functionality to define "withoutVersion" plugins in the Version catalog? I think it might come in handy in some cases, e.g. so you can generate type-safe accessors for precompiled scripts, or when the plugin is added to the classpath through methods where we cannot collect versions.

I did not tackle this in this PR, we have decided to save it for later. I filed #19302 to track this.

[bot-gradle]

OK, I've already triggered a build for you.

[bot-gradle]

Pre-tested commit build failed.

[octylFractal]

@bot-gradle test and merge

[bot-gradle]

OK, I've already triggered a build for you.