Add Elm language support

.nvmrc

@@ -0,0 +1 @@
+6.10.0

lib/travis/build.rb

@@ -38,6 +38,8 @@ def by_lang(lang)
           Script::ObjectiveC
         when 'bash', 'sh', 'shell' then
           Script::Generic
+        when 'elm' then
+          Script::Elm
         else
           name = lang.split('_').map { |w| w.capitalize }.join
           Script.const_get(name, false) rescue Script::Ruby

lib/travis/build/addons/deploy/script.rb

@@ -9,6 +9,7 @@ class Script
           VERSIONED_RUNTIMES = %w(
             d
             dart
+            elm
             elixir
             ghc
             go

lib/travis/build/script.rb

@@ -18,6 +18,7 @@
 require 'travis/build/script/csharp'
 require 'travis/build/script/d'
 require 'travis/build/script/dart'
+require 'travis/build/script/elm'
 require 'travis/build/script/erlang'
 require 'travis/build/script/elixir'
 require 'travis/build/script/go'

lib/travis/build/script/elm.rb

@@ -0,0 +1,113 @@
+module Travis
+  module Build
+    class Script
+      class Elm < NodeJs
+        DEFAULTS = {
+          elm_version: 'latest',
+          elm_test_version: 'latest'
+        }
+
+        def export
+          super
+          sh.export 'TRAVIS_ELM_VERSION', elm_version, echo: false
+          sh.export 'TRAVIS_ELM_TEST_VERSION', elm_test_version, echo: false
+        end
+
+        def configure
+          super
+
+          sh.if '! -d sysconfcpus/bin' do
+            install_sysconfcpus
+          end
+        end
+
+        def announce
+          super
+          sh.echo 'elm version:'
+          sh.cmd 'elm --version'
+
+          sh.echo 'elm-test version:'
+          sh.cmd 'elm-test --version'
+        end
+
+        def setup
+          super
+
+          install_elm
+          install_elm_test
+        end
+
+        def script
+          sh.cmd 'elm-format --validate .'
+          sh.cmd 'elm-test'
+        end
+
+        def setup_cache
+          if data.cache?(:elm)
+            sh.fold 'cache.elm' do
+              directory_cache.add '$HOME/.cache/elm-stuff', 'elm-stuff'
+
+              # some put their tests in ./test and others use ./tests
+              directory_cache.add '$HOME/.cache/elm-test-stuff', 'test/elm-stuff'
+              directory_cache.add '$HOME/.cache/elm-tests-stuff', 'tests/elm-stuff'
+
+              # we build sysconfcpus from source, so cache the result
+              directory_cache.add '$HOME/.cache/sysconfcpus-cache', 'sysconfcpus'
+            end
+          end
+        end
+
+        def cache_slug
+          super << '--elm-' << elm_version
+        end
+
+        private
+
+          def elm_version
+            config[:elm_version].to_s
+          end
+
+          def elm_test_version
+            config[:elm_test_version].to_s
+          end
+
+          def install_elm
+            npm_install '-g elm-use@">=1.1.0 <2.0.0"'
+            sh.cmd 'elm-use #{elm_version}', retry: true
+
+            convert_binary_to_sysconfcpus 'elm'
+            convert_binary_to_sysconfcpus 'elm-make'
+            convert_binary_to_sysconfcpus 'elm-package'
+            convert_binary_to_sysconfcpus 'elm-format'
+          end
+
+          def install_elm_test
+            npm_install '-g elm-test@#{elm_test_version}'
+
+            convert_binary_to_sysconfcpus 'elm-test'
+          end
+
+          def convert_binary_to_sysconfcpus(binary_name)
+            # Wrap the binary in a call to sysconfcpus -n 2
+            # to work around https://github.com/travis-ci/travis-ci/issues/6656
+            sh.mv "$(npm config get prefix)/bin/#{binary_name}", "$(npm config get prefix)/bin/#{binary_name}-old"
+
+            # Use printf instead of echo here.
+            # see https://github.com/rtfeldman/node-elm-compiler/pull/50
+            sh.cmd ('printf "#\041/bin/bash\n\necho \"Running ' + binary_name + ' with sysconfcpus -n 2\"\n\n$TRAVIS_BUILD_DIR/sysconfcpus/bin/sysconfcpus -n 2 ' + binary_name + '-old \"\$@\"" > $(npm config get prefix)/bin/' + binary_name)
+            sh.chmod '+x', "$(npm config get prefix)/bin/#{binary_name}"
+          end
+
+          def install_sysconfcpus
+            # this is a prerequisite for the convert_binary_to_sysconfcpus method
+            # which provides an epic build time improvement - see https://github.com/elm-lang/elm-compiler/issues/1473#issuecomment-245704142
+            sh.cmd 'git clone https://github.com/obmarg/libsysconfcpus.git', retry: true
+            sh.cd 'libsysconfcpus'
+            sh.cmd './configure --prefix=$TRAVIS_BUILD_DIR/sysconfcpus'
+            sh.cmd 'make && make install'
+            sh.cd '..'
+          end
+      end
+    end
+  end
+end

spec/build/script/elm_spec.rb

@@ -0,0 +1,39 @@
+require 'spec_helper'
+
+describe Travis::Build::Script::Elm, :sexp do
+  let(:data)   { payload_for(:push, :elm) }
+  let(:script) { described_class.new(data) }
+  subject      { script.sexp }
+  it           { store_example }
+
+  it_behaves_like 'compiled script' do
+    let(:code) { ['TRAVIS_LANGUAGE=elm'] }
+    let(:cmds) { ['elm-test'] }
+  end
+
+  it_behaves_like 'a build script sexp'
+
+  it 'sets TRAVIS_ELM_VERSION' do
+    should include_sexp [:export, ['TRAVIS_ELM_VERSION', 'latest']]
+  end
+
+  it 'sets TRAVIS_ELM_TEST_VERSION' do
+    should include_sexp [:export, ['TRAVIS_ELM_TEST_VERSION', 'latest']]
+  end
+
+  it 'announces elm version' do
+    should include_sexp [:cmd, 'elm --version', echo: true]
+    should include_sexp [:cmd, 'elm-test --version', echo: true]
+  end
+
+  describe 'script' do
+    it 'runs "elm-test"' do
+      should include_sexp [:cmd, 'elm-test', echo: true, timing: true]
+    end
+  end
+
+  describe '#cache_slug' do
+    subject { described_class.new(data).cache_slug }
+    it { is_expected.to eq("cache-#{CACHE_SLUG_EXTRAS}--elm-latest") }
+  end
+end