Propagate errors on deployment failures

We were not propagating the error from `deployLatest` through
to the CLI error result.  Despite out recent efforts to integrate
gometalinter, there were also several additional similar cases of
ignored error results reported by `errcheck`.  Not yet clear why
these are not being reported via gometalinter.

Fixes #262.

.gitignore

@@ -1,4 +1,5 @@
 *.swp
 /mu
 /vendor/
+/.vscode/
 

cmd/lumi/deploy.go

@@ -62,7 +62,7 @@ func newDeployCmd() *cobra.Command {
 			if err != nil {
 				return err
 			}
-			deployLatest(cmd, info, deployOptions{
+			err = deployLatest(cmd, info, deployOptions{
 				Destroy:            false,
 				DryRun:             dryRun,
 				Analyzers:          analyzers,
@@ -73,7 +73,7 @@ func newDeployCmd() *cobra.Command {
 				Summary:            summary,
 				Output:             output,
 			})
-			return nil
+			return err
 		}),
 	}
 

cmd/lumi/destroy.go

@@ -46,11 +46,14 @@ func newDestroyCmd() *cobra.Command {
 			name := info.Target.Name
 			if dryRun || yes ||
 				confirmPrompt("This will permanently destroy all resources in the '%v' environment!", name) {
-				deployLatest(cmd, info, deployOptions{
+				err = deployLatest(cmd, info, deployOptions{
 					Destroy: true,
 					DryRun:  dryRun,
 					Summary: summary,
 				})
+				if err != nil {
+					return err
+				}
 			}
 			return nil
 		}),

cmd/lumi/env.go

@@ -220,7 +220,9 @@ func removeTarget(env *deploy.Target) {
 // simply renames the file, which is simpler, more efficient, etc.
 func backupTarget(file string) {
 	contract.Require(file != "", "file")
-	os.Rename(file, file+".bak") // ignore errors.
+	if err := os.Rename(file, file+".bak"); err != nil {
+		// ignore errors.
+	}
 	// IDEA: consider multiple backups (.bak.bak.bak...etc).
 }
 

cmd/lumi/pack_eval.go

@@ -62,7 +62,9 @@ func newPackEvalCmd() *cobra.Command {
 				if err != nil {
 					return err
 				}
-				deploy.InitEvalConfig(result.B.Ctx(), e, envInfo.Target.Config)
+				if err := deploy.InitEvalConfig(result.B.Ctx(), e, envInfo.Target.Config); err != nil {
+					return err
+				}
 			}
 
 			// Finally, execute the entire program, and serialize the return value (if any).

pkg/resource/deploy/source_eval.go

@@ -100,7 +100,9 @@ func (src *evalSource) Iterate() (SourceIterator, error) {
 	src.plugctx.SetCurrentInterpreter(e)
 
 	// Now create the evaluator coroutine and prepare it to take its first step.
-	forkEval(src, rz, e)
+	if err := forkEval(src, rz, e); err != nil {
+		return nil, err
+	}
 
 	// Finally, return the fresh iterator that can take things from here.
 	return &evalSourceIterator{