Automatically fetch latest ruby-build version with 24h cache

Author: exterm

.gitignore

@@ -1 +1,3 @@
 ruby-build
+ruby-build-source
+.ruby-build-version-cache

README.md

@@ -27,14 +27,20 @@ RUBY_APPLY_PATCHES=$'dir/1.patch\n2.patch\nhttp://example.com/3.patch' asdf inst
 RUBY_APPLY_PATCHES=$(curl -s https://raw.githubusercontent.com/rvm/rvm/master/patchsets/ruby/2.1.1/railsexpress) asdf install ruby 2.1.1
 ```
 
-> [!NOTE]
-> This plugin does not automatically fetch new Ruby versions. Running `asdf plugin update ruby` will update asdf-ruby and ensure the latest versions of Ruby are available to install. If the desired ruby version is still not showing up see the below [Troubleshooting](https://github.com/asdf-vm/asdf-ruby?tab=readme-ov-file#troubleshooting) section.
+By default asdf-ruby automatically fetches the latest release of ruby-build, so new Ruby versions are available as soon as ruby-build supports them.
 
-By default asdf-ruby uses a recent release of ruby-build, however instead you can choose your own branch/tag through the `ASDF_RUBY_BUILD_VERSION` variable:
+You can override this behavior with the following environment variables:
 
-```
-ASDF_RUBY_BUILD_VERSION=master asdf install ruby 2.6.4
-```
+- `ASDF_RUBY_BUILD_VERSION` - Pin to a specific ruby-build version/branch/tag:
+  ```
+  ASDF_RUBY_BUILD_VERSION=v20240101 asdf install ruby 3.3.0
+  ASDF_RUBY_BUILD_VERSION=master asdf install ruby 3.3.0
+  ```
+
+- `ASDF_RUBY_BUILD_CACHE_CLEAR` - Bypass the 24-hour cache and fetch the latest version:
+  ```
+  ASDF_RUBY_BUILD_CACHE_CLEAR=1 asdf list-all ruby
+  ```
 
 ## Default gems
 
@@ -68,7 +74,7 @@ note that you might have to change `.ruby-version` to include full version (e.g.
 ## Troubleshooting
 
 > [!NOTE]
-> The most common issue reported for this plugin is a missing Ruby version. If you are not seeing a recent Ruby version in the list of available Ruby versions it's likely due to having an older version of this plugin. Run `asdf plugin update ruby` to get the most recent list of Ruby versions. If it is still not showing up then this plugin's `RUBY_BUILD_VERSION` in lib/utils.sh likely needs updated with the latest ruby-build release https://github.com/rbenv/ruby-build/releases. Please check for an existing PR before submitting a new one. If there is not one, please fork the repo and submit one. If this plugin's ruby-build needs updated, you can workaround it with `ASDF_RUBY_BUILD_VERSION`. A note in the above [Use](https://github.com/asdf-vm/asdf-ruby?tab=readme-ov-file#use) section describes how to do this.  
+> If you are not seeing a recent Ruby version, try bypassing the version cache with `ASDF_RUBY_BUILD_CACHE_CLEAR=1 asdf list-all ruby` to fetch the latest ruby-build version. If the version still doesn't appear, check ruby-build's releases at https://github.com/rbenv/ruby-build/releases to see if it's been added yet.  
 
 If you are moving to asdf-ruby from another Ruby version manager, it is recommended to completely uninstall the old Ruby version manager before installing asdf-ruby.
 

lib/utils.sh

@@ -1,8 +1,5 @@
 #!/usr/bin/env bash
 
-RUBY_BUILD_VERSION="${ASDF_RUBY_BUILD_VERSION:-v20260114}"
-RUBY_BUILD_TAG="$RUBY_BUILD_VERSION"
-
 echoerr() {
   echo >&2 -e "\033[0;31m$1\033[0m"
 }
@@ -17,30 +14,39 @@ ensure_ruby_build_setup() {
 }
 
 ensure_ruby_build_installed() {
-  local current_ruby_build_version
+  local current_ruby_build_version target_version
+
+  target_version="$(get_ruby_build_version)"
 
   if [ ! -f "$(ruby_build_path)" ]; then
-    download_ruby_build
-  else
+    # No ruby-build installed - we must have a version to download
+    if [ -z "$target_version" ]; then
+      errorexit "Could not determine ruby-build version. Check your network connection."
+    fi
+    download_ruby_build "$target_version"
+  elif [ -n "$target_version" ]; then
+    # ruby-build exists and we have a target version - check if update needed
     current_ruby_build_version="$("$(ruby_build_path)" --version | cut -d ' ' -f2)"
     # If ruby-build version does not start with 'v',
     # add 'v' to beginning of version
     # shellcheck disable=SC2086
     if [ ${current_ruby_build_version:0:1} != "v" ]; then
       current_ruby_build_version="v$current_ruby_build_version"
     fi
-    if [ "$current_ruby_build_version" != "$RUBY_BUILD_VERSION" ]; then
+    if [ "$current_ruby_build_version" != "$target_version" ]; then
       # If the ruby-build directory already exists and the version does not
       # match, remove it and download the correct version
       rm -rf "$(ruby_build_dir)"
-      download_ruby_build
+      download_ruby_build "$target_version"
     fi
   fi
+  # If ruby-build exists but we couldn't get a target version, just use what's installed
 }
 
 download_ruby_build() {
+  local version="$1"
   # Print to stderr so asdf doesn't assume this string is a list of versions
-  echoerr "Downloading ruby-build..."
+  echoerr "Downloading ruby-build ${version}..."
   # shellcheck disable=SC2155
   local build_dir="$(ruby_build_source_dir)"
 
@@ -51,11 +57,13 @@ download_ruby_build() {
   git clone https://github.com/rbenv/ruby-build.git "$build_dir" >/dev/null 2>&1
   (
     cd "$build_dir" || exit
-    git checkout "$RUBY_BUILD_TAG" >/dev/null 2>&1
+    git checkout "$version" >/dev/null 2>&1
   )
 
-  # Install in the ruby-build dir
-  PREFIX="$(ruby_build_dir)" "$build_dir/install.sh"
+  # Install in the ruby-build dir (must use absolute path as install.sh changes directory)
+  local install_dir
+  install_dir="$(cd "$(asdf_ruby_plugin_path)" && pwd)/ruby-build"
+  PREFIX="$install_dir" "$build_dir/install.sh"
 
   # Remove ruby-build source dir
   rm -rf "$build_dir"
@@ -76,3 +84,75 @@ ruby_build_source_dir() {
 ruby_build_path() {
   echo "$(ruby_build_dir)/bin/ruby-build"
 }
+
+ruby_build_version_cache_path() {
+  echo "$(asdf_ruby_plugin_path)/.ruby-build-version-cache"
+}
+
+# Get file modification time in seconds since epoch (cross-platform)
+get_file_mtime() {
+  local file="$1"
+  # Try GNU stat first (Linux), then BSD stat (macOS)
+  stat -c %Y "$file" 2>/dev/null || stat -f %m "$file" 2>/dev/null
+}
+
+# Fetch the latest ruby-build version tag from GitHub
+fetch_latest_ruby_build_version() {
+  timeout 10 git ls-remote --tags --sort=-version:refname https://github.com/rbenv/ruby-build.git 2>/dev/null |
+    grep -oE 'refs/tags/v[0-9]+$' |
+    head -1 |
+    sed 's|refs/tags/||'
+}
+
+# Get the ruby-build version to use, with caching
+# Priority: ASDF_RUBY_BUILD_VERSION env var > cached latest > fetched latest > installed version
+get_ruby_build_version() {
+  # If user explicitly set a version, use that
+  if [ -n "${ASDF_RUBY_BUILD_VERSION:-}" ]; then
+    echo "$ASDF_RUBY_BUILD_VERSION"
+    return 0
+  fi
+
+  local cache_file
+  cache_file="$(ruby_build_version_cache_path)"
+
+  # Check cache first (unless ASDF_RUBY_BUILD_CACHE_CLEAR is set)
+  if [ -z "${ASDF_RUBY_BUILD_CACHE_CLEAR:-}" ] && [ -f "$cache_file" ]; then
+    local cache_mtime current_time age
+    cache_mtime="$(get_file_mtime "$cache_file")"
+    current_time="$(date +%s)"
+    age=$((current_time - cache_mtime))
+
+    # Cache for 24 hours
+    if [ "$age" -lt 86400 ]; then
+      cat "$cache_file"
+      return 0
+    fi
+  fi
+
+  # Fetch latest version from GitHub
+  local latest_version
+  latest_version="$(fetch_latest_ruby_build_version)"
+
+  if [ -n "$latest_version" ]; then
+    echo "$latest_version" >"$cache_file"
+    echo "$latest_version"
+    return 0
+  fi
+
+  # Fallback: if ruby-build is already installed, use its version
+  # (if we can't reach GitHub, we likely can't download a new version anyway)
+  if [ -f "$(ruby_build_path)" ]; then
+    local installed_version
+    installed_version="$("$(ruby_build_path)" --version | cut -d ' ' -f2)"
+    if [ "${installed_version:0:1}" != "v" ]; then
+      installed_version="v$installed_version"
+    fi
+    echoerr "Warning: Could not fetch latest ruby-build version, using installed version ${installed_version}"
+    echo "$installed_version"
+    return 0
+  fi
+
+  # No version available
+  return 1
+}