feat(ruby)!: rewrite to use ruby-build with optional rbenv/rvm (v2.0.0)

Replace the rvm-only install with ruby-build under /usr/local/rubies,
exposed via the 'current' symlink on the PATH. Add a versionManager
option ("none" | "rbenv" | "rvm") that installs the chosen manager
and delegates 'install' to it.

Detect build deps across apt, dnf/yum, apk, zypper, and pacman.
Replace ruby_fallback_test with ruby_rbenv / ruby_rvm scenarios.

Author: rhiroe

src/ruby/NOTES.md

@@ -2,6 +2,13 @@
 
 ## OS Support
 
-This Feature should work on recent versions of Debian/Ubuntu-based distributions with the `apt` package manager installed.
+This Feature supports Linux images that ship one of the following package managers: `apt`, `dnf`/`yum`, `apk`, `zypper`, or `pacman`. The script detects the available package manager and installs the build dependencies that ruby-build needs.
 
 `bash` is required to execute the `install.sh` script.
+
+## Layout
+
+- Ruby is installed under `/usr/local/rubies/<version>` by ruby-build.
+- The default Ruby is exposed via the `/usr/local/rubies/current` symlink, which is placed on the `PATH` through `containerEnv`.
+- `ruby-build` itself is cloned to `/usr/local/share/ruby-build` and symlinked into `/usr/local/bin/ruby-build` so additional versions can be installed later.
+- A shared `ruby` group owns `/usr/local/rubies`; the configured non-root user is added to it so `gem install` can write into the active Ruby tree without `sudo`.

src/ruby/README.md

@@ -1,13 +1,13 @@
 
-# Ruby (via rvm) (ruby)
+# Ruby (via ruby-build) (ruby)
 
-Installs Ruby, rvm, rbenv, common Ruby utilities, and needed dependencies.
+Installs Ruby using ruby-build only (no rvm, no rbenv), along with common build dependencies.
 
 ## Example Usage
 
 ```json
 "features": {
-    "ghcr.io/devcontainers/features/ruby:1": {}
+    "ghcr.io/devcontainers/features/ruby:2": {}
 }
 ```
 
@@ -27,7 +27,7 @@ Installs Ruby, rvm, rbenv, common Ruby utilities, and needed dependencies.
 
 ## OS Support
 
-This Feature should work on recent versions of Debian/Ubuntu-based distributions with the `apt` package manager installed.
+This Feature supports Linux images that ship one of the following package managers: `apt`, `dnf`/`yum`, `apk`, `zypper`, or `pacman`. The script detects the available package manager and installs the build dependencies that ruby-build needs.
 
 `bash` is required to execute the `install.sh` script.
 

src/ruby/devcontainer-feature.json

@@ -1,20 +1,26 @@
 {
     "id": "ruby",
-    "version": "1.3.2",
-    "name": "Ruby (via rvm)",
+    "version": "2.0.0",
+    "name": "Ruby (via ruby-build)",
     "documentationURL": "https://github.com/devcontainers/features/tree/main/src/ruby",
-    "description": "Installs Ruby, rvm, rbenv, common Ruby utilities, and needed dependencies.",
+    "description": "Installs Ruby using ruby-build, with optional rbenv or rvm for version management.",
     "options": {
         "version": {
             "type": "string",
             "proposals": [
                 "latest",
                 "none",
-                "3.4",
-                "3.2"
+                "4.0",
+                "3.4"
             ],
             "default": "latest",
             "description": "Select or enter a Ruby version to install"
+        },
+        "versionManager": {
+            "type": "string",
+            "enum": ["none", "rbenv", "rvm"],
+            "default": "none",
+            "description": "Version manager to install alongside Ruby: 'rbenv', 'rvm', or 'none' (ruby-build only)"
         }
     },
     "customizations": {
@@ -25,17 +31,15 @@
             "settings": {
                 "github.copilot.chat.codeGeneration.instructions": [
                     {
-                        "text": "This dev container includes Ruby, rvm, rbenv, common Ruby utilities, and needed dependencies pre-installed and available on the `PATH`, along with the Ruby language extension for Ruby development."
+                        "text": "This dev container installs Ruby via ruby-build. rbenv or rvm may also be available depending on the versionManager option. The default Ruby is on the PATH via /usr/local/rubies/current/bin (or rbenv shims if rbenv is the version manager)."
                     }
                 ]
             }
         }
     },
     "containerEnv": {
-        "GEM_PATH": "/usr/local/rvm/gems/default:/usr/local/rvm/gems/default@global",
-        "GEM_HOME": "/usr/local/rvm/gems/default",
-        "MY_RUBY_HOME": "/usr/local/rvm/rubies/default",
-        "PATH": "/usr/local/rvm/gems/default/bin:/usr/local/rvm/gems/default@global/bin:/usr/local/rvm/rubies/default/bin:/usr/local/share/rbenv/bin:${PATH}"
+        "RBENV_ROOT": "/usr/local/share/rbenv",
+        "PATH": "/usr/local/share/rbenv/shims:/usr/local/share/rbenv/bin:/usr/local/rubies/current/bin:${PATH}"
     },
     "installsAfter": [
         "ghcr.io/devcontainers/features/common-utils"