Gradle cannot resolve plugin versions from the plugin portal that contain a plus character

[mstr2]

Expected Behavior

I expect Gradle to correctly resolve plugin versions from the plugin portal that contain a + character.

Current Behavior

Consider the following plugin: org.jfxcore.javafxplugin:18-ea+1. Applying the plugin produces the following error message:

> Could not find org.jfxcore:gradle-plugin:18-ea+1.
     Searched in the following locations:
       - https://plugins.gradle.org/m2/org/jfxcore/gradle-plugin/18-ea+1/gradle-plugin-18-ea+1.pom
     If the artifact you are trying to retrieve can be found in the repository but without metadata in 'Maven POM' format, you need to adjust the 'metadataSources { ... }' of the repository declaration.
     Required by:
         project : > org.jfxcore.javafxplugin:org.jfxcore.javafxplugin.gradle.plugin:18-ea+1

The error seems to originate with an attempt by Gradle to incorrectly resolve a URL redirect, which then fails with Resource missing:

[INFO] [org.gradle.internal.resource.transport.http.HttpClientHelper] Resource missing. [HTTP GET: https://plugins-artifacts.gradle.org/org.jfxcore/gradle-plugin/18-ea+1/52bec557dd69672aad080647989c92bb3fe375d33117bd027a9d43a5782ae365/gradle-plugin-18-ea+1.pom]

The underlying reason is the following:
When Gradle tries to resolve the plugin's POM file gradle-plugin-18-ea+1.pom, plugins.gradle.org returns 303 See Other.
The redirected URL of the POM file contains an escaped notation of the plugin version: gradle-plugin-18-ea%2B1.pom (note that + was escaped by %2B).

For reference, this wget call shows what is happening when I'm trying to download the gradle-plugin-18-ea+1.pom file from plugins.gradle.org:

wget https://plugins.gradle.org/m2/org/jfxcore/gradle-plugin/18-ea+1/gradle-plugin-18-ea+1.pom
--2022-07-27 14:31:10--  https://plugins.gradle.org/m2/org/jfxcore/gradle-plugin/18-ea+1/gradle-plugin-18-ea+1.pom
Resolving plugins.gradle.org (plugins.gradle.org)... 104.18.190.9, 104.18.191.9, 2606:4700::6812:be09, ...
Connecting to plugins.gradle.org (plugins.gradle.org)|104.18.190.9|:443... connected.
HTTP request sent, awaiting response... 303 See Other
Location: https://plugins-artifacts.gradle.org/org.jfxcore/gradle-plugin/18-ea%2B1/52bec557dd69672aad080647989c92bb3fe375d33117bd027a9d43a5782ae365/gradle-plugin-18-ea%2B1.pom [following]
--2022-07-27 14:31:10--  https://plugins-artifacts.gradle.org/org.jfxcore/gradle-plugin/18-ea%2B1/52bec557dd69672aad080647989c92bb3fe375d33117bd027a9d43a5782ae365/gradle-plugin-18-ea%2B1.pom
Resolving plugins-artifacts.gradle.org (plugins-artifacts.gradle.org)... 104.18.190.9, 104.18.191.9, 2606:4700::6812:bf09, ...
Connecting to plugins-artifacts.gradle.org (plugins-artifacts.gradle.org)|104.18.190.9|:443... connected.
HTTP request sent, awaiting response... 200 OK
Length: 1950 (1.9K) [binary/octet-stream]
Saving to: ‘gradle-plugin-18-ea+1.pom’

Note that the repository plugins-artifacts.gradle.org contains the gradle-plugin-18-ea%2B1.pom artifact (where + is escaped), but it does not allow this artifact to be retrieved with an unescaped URL (that contains + instead of %2B).

Yet this is what Gradle seems to be doing, and as a result, it fails to find the artifact.