Use jvm buildpack to install JRuby dependencies

CHANGELOG.md

@@ -1,5 +1,7 @@
 # Main (unreleased)
 
+* Ruby buildpack now relies on the JVM buildpack to install java for Jruby apps (https://github.com/heroku/heroku-buildpack-ruby/pull/1119)
+
 ## v223 (1/22/2021)
 
 * Fix Gemfile.lock read bug from preventing propper removal of BUNDLED WITH declaration (https://github.com/heroku/heroku-buildpack-ruby/pull/1108)

bin/compile

@@ -2,10 +2,30 @@
 # The actual compilation code lives in `bin/support/ruby_compile`. This file instead
 # bootstraps the ruby needed and then executes `bin/support/ruby_compile`
 
+BUILD_DIR=$1
+CACHE_DIR=$2
+ENV_DIR=$3
 BIN_DIR=$(cd $(dirname $0); pwd)
 BUILDPACK_DIR=$(dirname $BIN_DIR)
 
 source "$BIN_DIR/support/bash_functions.sh"
 heroku_buildpack_ruby_install_ruby "$BIN_DIR" "$BUILDPACK_DIR"
 
+if detect_needs_java "$BUILD_DIR"; then
+  cat <<EOM
+
+       ## Warning: Your app needs java
+
+       The Ruby buildpack determined your app needs java installed
+       we recommend you add the jvm buildpack to your application:
+
+         $ heroku buildpacks:add heroku/jvm --index=1
+
+-----> Installing Java
+
+EOM
+
+  compile_buildpack_v2 "$BUILD_DIR" "$CACHE_DIR" "$ENV_DIR" "https://buildpack-registry.s3.amazonaws.com/buildpacks/heroku/jvm.tgz" "heroku/jvm"
+fi
+
 $heroku_buildpack_ruby_dir/bin/ruby $BIN_DIR/support/ruby_compile $@

bin/support/bash_functions.sh

@@ -1,3 +1,15 @@
+#!/usr/bin/env bash
+
+curl_retry_on_18() {
+  local ec=18;
+  local attempts=0;
+  while (( ec == 18 && attempts++ < 3 )); do
+    curl "$@" # -C - would return code 33 if unsupported by server
+    ec=$?
+  done
+  return $ec
+}
+
 # This function will install a version of Ruby onto the
 # system for the buidlpack to use. It coordinates download
 # and setting appropriate env vars for execution
@@ -44,3 +56,100 @@ heroku_buildpack_ruby_install_ruby()
   export PATH=$heroku_buildpack_ruby_dir/bin/:$PATH
   unset GEM_PATH
 }
+
+which_java()
+{
+  which java > /dev/null
+}
+
+# Detects if a given Gemfile.lock has jruby in it
+# $ cat Gemfile.lock | grep jruby # => ruby 2.5.7p001 (jruby 9.2.13.0)
+detect_needs_java()
+{
+  local app_dir=$1
+  local gemfile_lock="$app_dir/Gemfile.lock"
+  # local needs_jruby=0
+  local skip_java_install=1
+
+  if which_java; then
+    return $skip_java_install
+  fi
+  grep "(jruby " "$gemfile_lock" --quiet
+}
+
+# Runs another buildpack against the build dir
+#
+# Example:
+#
+#   compile_buildpack_v2 "$build_dir" "$cache_dir" "$env_dir" "https://buildpack-registry.s3.amazonaws.com/buildpacks/heroku/nodejs.tgz" "heroku/nodejs"
+#
+compile_buildpack_v2()
+{
+  local build_dir=$1
+  local cache_dir=$2
+  local env_dir=$3
+  local buildpack=$4
+  local name=$5
+
+  local dir
+  local url
+  local branch
+
+  dir=$(mktemp -t buildpackXXXXX)
+  rm -rf "$dir"
+
+  url=${buildpack%#*}
+  branch=${buildpack#*#}
+
+  if [ "$branch" == "$url" ]; then
+    branch=""
+  fi
+
+  if [ "$url" != "" ]; then
+    echo "-----> Downloading Buildpack: ${name}"
+
+    if [[ "$url" =~ \.tgz$ ]] || [[ "$url" =~ \.tgz\? ]]; then
+      mkdir -p "$dir"
+      curl_retry_on_18 -s "$url" | tar xvz -C "$dir" >/dev/null 2>&1
+    else
+      git clone "$url" "$dir" >/dev/null 2>&1
+    fi
+    cd "$dir" || return
+
+    if [ "$branch" != "" ]; then
+      git checkout "$branch" >/dev/null 2>&1
+    fi
+
+    # we'll get errors later if these are needed and don't exist
+    chmod -f +x "$dir/bin/{detect,compile,release}" || true
+
+    framework=$("$dir"/bin/detect "$build_dir")
+
+    # shellcheck disable=SC2181
+    if [ $? == 0 ]; then
+      echo "-----> Detected Framework: $framework"
+      "$dir"/bin/compile "$build_dir" "$cache_dir" "$env_dir"
+
+      # shellcheck disable=SC2181
+      if [ $? != 0 ]; then
+        exit 1
+      fi
+
+      # check if the buildpack left behind an environment for subsequent ones
+      if [ -e "$dir/export" ]; then
+        set +u # http://redsymbol.net/articles/unofficial-bash-strict-mode/#sourcing-nonconforming-document
+        # shellcheck disable=SC1090
+        source "$dir/export"
+        set -u # http://redsymbol.net/articles/unofficial-bash-strict-mode/#sourcing-nonconforming-document
+      fi
+
+      if [ -x "$dir/bin/release" ]; then
+        "$dir"/bin/release "$build_dir" > "$1"/last_pack_release.out
+      fi
+    else
+      echo "Couldn't detect any framework for this buildpack. Exiting."
+      exit 1
+    fi
+  fi
+}
+

bin/test-compile

@@ -2,10 +2,30 @@
 # The actual `bin/test-compile` code lives in `bin/ruby_test-compile`. This file instead
 # bootstraps the ruby needed and then executes `bin/ruby_test-compile`
 
+BUILD_DIR=$1
+CACHE_DIR=$2
+ENV_DIR=$3
 BIN_DIR=$(cd $(dirname $0); pwd)
 BUILDPACK_DIR=$(dirname $BIN_DIR)
 
 source "$BIN_DIR/support/bash_functions.sh"
 heroku_buildpack_ruby_install_ruby "$BIN_DIR" "$BUILDPACK_DIR"
 
+if detect_needs_java "$BUILD_DIR"; then
+  cat <<EOM
+
+       ## Warning: Your app needs java
+
+       The Ruby buildpack determined your app needs java installed
+       we recommend you add the jvm buildpack to your application:
+
+         $ heroku buildpacks:add heroku/jvm --index=1
+
+-----> Installing Java
+
+EOM
+
+  compile_buildpack_v2 "$BUILD_DIR" "$CACHE_DIR" "$ENV_DIR" "https://buildpack-registry.s3.amazonaws.com/buildpacks/heroku/jvm.tgz" "heroku/jvm"
+fi
+
 $heroku_buildpack_ruby_dir/bin/ruby $BIN_DIR/support/ruby_test-compile $@

changelogs/unreleased/jvm_installer_default.md

@@ -0,0 +1,13 @@
+## JVM support for JRuby apps is now provided by the `heroku/jvm` buildpack
+
+JRuby applications require the JVM to run. Before this change, the JVM for JRuby apps was provided by the `heroku/ruby` buildpack for JRuby applications.
+
+Now the custom JVM installation logic in the `heroku/ruby` buildpack has been removed, and instead, the `heroku/jvm` buildpack will be called directly by the Ruby buildpack.
+
+Instead of relying on this functionality, it is recommended to manually require the `heroku/jvm` buildpack for your application:
+
+```
+$ heroku buildpacks:add heroku/jvm --index=1
+```
+
+For more information on JRuby support, see the [Heroku Ruby Support page](https://devcenter.heroku.com/articles/ruby-support).

hatchet.json

@@ -22,7 +22,6 @@
     "sharpstone/cd_ruby",
     "sharpstone/ruby_193_jruby_173",
     "sharpstone/ruby_193_jruby_176",
-    "sharpstone/ruby_193_jruby_1_7_27",
     "sharpstone/ruby_193_jruby_17161_jdk7",
     "sharpstone/ruby_193_bad_patch_cedar_14",
     "sharpstone/ruby_25",

hatchet.lock

@@ -95,8 +95,6 @@
   - a08e8b2cc61d08bd611accaa455dbcbfff80f831
 - - "./repos/ruby/ruby_193_jruby_176"
   - 9fcbc184cb386abc8784e9935d52d403e35c532c
-- - "./repos/ruby/ruby_193_jruby_1_7_27"
-  - 06d5e86180ff0e5b6894f823736cd649dcfebed4
 - - "./repos/ruby/ruby_25"
   - 0cb3df80d55b61e9417f2ac00adb06e15ae37982
 - - "./repos/ruby/ruby_version_does_not_exist"