Merge pull request #1661 from Shopify/handle-npm-list-bad-status

Handle `npm list` non-zero exit status

lib/project_types/script/layers/infrastructure/languages/assemblyscript_task_runner.rb

@@ -49,12 +49,31 @@ def metadata
 
           def library_version(library_name)
             output = JSON.parse(CommandRunner.new(ctx: ctx).call("npm list --json"))
-            raise Errors::APILibraryNotFoundError.new(library_name), output unless output["dependencies"][library_name]
-            output["dependencies"][library_name]["version"]
+            library_version_from_npm_list(output, library_name)
+          rescue Errors::SystemCallFailureError => error
+            library_version_from_npm_list_error_output(error, library_name)
           end
 
           private
 
+          def library_version_from_npm_list_error_output(error, library_name)
+            # npm list can return a failure status code, even when returning the correct data.
+            # This causes the CommandRunner to throw a SystemCallFailure error that contains the data.
+            # In here, we check that the output contains `npm list`'s structure and extract the version.
+            output = JSON.parse(error.out)
+            raise error unless output.key?("dependencies")
+
+            library_version_from_npm_list(output, library_name)
+          rescue JSON::ParserError
+            raise error
+          end
+
+          def library_version_from_npm_list(output, library_name)
+            output.dig("dependencies", library_name, "version").tap do |version|
+              raise Errors::APILibraryNotFoundError, library_name unless version
+            end
+          end
+
           def check_node_version!
             output, status = @ctx.capture2e("node", "--version")
             raise Errors::DependencyInstallError, output unless status.success?

test/project_types/script/layers/infrastructure/languages/assemblyscript_task_runner_test.rb

@@ -148,14 +148,54 @@
     end
 
     describe "when CommandRunner raises SystemCallFailureError" do
-      it "should raise SystemCallFailureError" do
-        cmd = "npm list --json"
-        command_runner.any_instance.stubs(:call)
-          .with(cmd)
-          .raises(Script::Layers::Infrastructure::Errors::SystemCallFailureError.new(out: "test", cmd: cmd))
+      describe "when error is not json" do
+        it "should re-raise SystemCallFailureError" do
+          cmd = "npm list --json"
+          command_runner.any_instance.stubs(:call)
+            .with(cmd)
+            .raises(Script::Layers::Infrastructure::Errors::SystemCallFailureError.new(
+out: "some non-json parsable error output", cmd: cmd
+))
+
+          assert_raises Script::Layers::Infrastructure::Errors::SystemCallFailureError do
+            subject
+          end
+        end
+      end
 
-        assert_raises Script::Layers::Infrastructure::Errors::SystemCallFailureError do
-          subject
+      describe "when error is json, but doesn't contain the expected structure" do
+        it "should re-raise SystemCallFailureError" do
+          cmd = "npm list --json"
+          command_runner.any_instance.stubs(:call)
+            .with(cmd)
+            .raises(Script::Layers::Infrastructure::Errors::SystemCallFailureError.new(
+              out: {
+                "not what we expected" => {},
+              }.to_json,
+              cmd: cmd
+            ))
+          assert_raises Script::Layers::Infrastructure::Errors::SystemCallFailureError do
+            subject
+          end
+        end
+      end
+
+      describe "when error contains expected versioning data" do
+        it "should rescue SystemCallFailureError if the library version is present" do
+          cmd = "npm list --json"
+          command_runner.any_instance.stubs(:call)
+            .with(cmd)
+            .raises(Script::Layers::Infrastructure::Errors::SystemCallFailureError.new(
+              out: {
+                "dependencies" => {
+                  extension_point_config["assemblyscript"][:package] => {
+                    "version" => "1.3.7",
+                  },
+                },
+              }.to_json,
+              cmd: cmd
+            ))
+          assert_equal "1.3.7", subject
         end
       end
     end