From 89912d2ba77252fe322098ac3adc05428772e827 Mon Sep 17 00:00:00 2001
From: Sean Doyle <sean.p.doyle24@gmail.com>
Date: Thu, 17 Mar 2016 13:51:33 -0400
Subject: [PATCH] Fail `ember:compile` if build subprocess fails

Closes [#417].

The following is the command `ember-cli-rails` generates for `rake
ember:compile`. It was generated using [the example application][repo].

```bash
/Users/seanpdoyle/src/ember-cli-rails-heroku-example/frontend/node_modules/.bin/ember build --environment 'development' --output-path '/Users/seanpdoyle/src/ember-cli-rails-heroku-example/tmp/ember-cli/apps/frontend' | /usr/bin/tee -a '/Users/seanpdoyle/src/ember-cli-rails-heroku-example/log/ember-frontend.development.log'

Pipes are streaming, so the pipe to `tee` will open before the first
program finishes writing, potentially ignoring a non-zero exit status.

The solution is to set the [`pipefail`][docs] option for the generated
sub-command.

[repo]: https://github.com/seanpdoyle/ember-cli-rails-heroku-example
[#417]: https://github.com/thoughtbot/ember-cli-rails/issues/417
[docs]: http://www.gnu.org/software/bash/manual/html_node/Pipelines.html
---
 lib/ember_cli/command.rb           | 2 +-
 spec/lib/ember_cli/command_spec.rb | 7 +++++++
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/lib/ember_cli/command.rb b/lib/ember_cli/command.rb
index 054c4d3e..60ea02b7 100644
--- a/lib/ember_cli/command.rb
+++ b/lib/ember_cli/command.rb
@@ -14,7 +14,7 @@ def test
     end
 
     def build(watch: false)
-      "#{ember_build(watch: watch)} | #{tee}"
+      "set -o pipefail; #{ember_build(watch: watch)} | #{tee}"
     end
 
     private
diff --git a/spec/lib/ember_cli/command_spec.rb b/spec/lib/ember_cli/command_spec.rb
index 4b93812f..26cbcb09 100644
--- a/spec/lib/ember_cli/command_spec.rb
+++ b/spec/lib/ember_cli/command_spec.rb
@@ -25,6 +25,13 @@
       expect(command.build).to match(%r{\| path/to/tee -a 'path/to/log'})
     end
 
+    it "sets pipefail" do
+      paths = build_paths(tee: "path/to/tee", log: "path/to/log")
+      command = build_command(paths: paths)
+
+      expect(command.build).to match(%r{\Aset -o pipefail;})
+    end
+
     context "when building in production" do
       it "includes the `--environment production` flag" do
         paths = build_paths