Merge pull request #452 from chef/ssd/builder-shasum-fix

Cache Builder#shasum before Builder#build to ensure consistent result

lib/omnibus/builder.rb

@@ -580,7 +580,8 @@ module Omnibus
     #
     def build
       log.info(log_key) { 'Starting build' }
-
+      shasum # ensure shashum is calculated before build since the build can alter the shasum
+      log.internal(log_key) { 'Cached builder checksum before build: #{shasum}'}
       if software.overridden?
         log.info(log_key) do
           "Version overridden from #{software.default_version} to "\

lib/omnibus/software.rb

@@ -519,7 +519,7 @@ module Omnibus
           }
         )
       end
- 
+
       env.merge(compiler_flags).
         merge(extra_linker_flags).
         # always want to favor pkg-config from embedded location to not hose

spec/unit/builder_spec.rb

@@ -180,5 +180,38 @@ module Omnibus
         subject.make(timeout: 3600)
       end
     end
+
+    describe "#shasum" do
+      let(:build_step) do
+        Proc.new {
+          block do
+            command("true")
+          end
+        }
+      end
+
+      let(:tmp_dir) { Dir.mktmpdir }
+      after { FileUtils.rmdir(tmp_dir) }
+
+      let(:software) do
+        double(Software,
+               name: 'chefdk',
+               install_dir: tmp_dir,
+               project_dir: tmp_dir,
+               overridden?: false)
+      end
+
+      let(:before_build_shasum) do
+        b = described_class.new(software)
+        b.evaluate(&build_step)
+        b.shasum
+      end
+
+      it "returns the same value when called before or after the build" do
+        subject.evaluate(&build_step)
+        subject.build
+        expect(subject.shasum).to eq(before_build_shasum)
+      end
+    end
   end
 end