Be verbose and don't update files during dry-run

Author: carolynvs

cmd/dep/ensure.go

@@ -119,7 +119,7 @@ func (cmd *ensureCommand) Run(ctx *dep.Ctx, args []string) error {
 	defer sm.Release()
 
 	params := p.MakeParams()
-	if *verbose {
+	if *verbose || cmd.dryRun {
 		params.Trace = true
 		params.TraceLogger = log.New(os.Stderr, "", 0)
 	}
@@ -165,6 +165,10 @@ func (cmd *ensureCommand) Run(ctx *dep.Ctx, args []string) error {
 	}
 	writeV := !vendorExists && solution != nil
 
+	if cmd.dryRun {
+		return nil
+	}
+
 	return errors.Wrap(sw.WriteAllSafe(writeV), "grouped write of manifest, lock and vendor")
 }
 

cmd/dep/ensure_test.go

@@ -9,6 +9,7 @@ import (
 
 	"github.com/golang/dep/test"
 	"github.com/sdboyer/gps"
+	"path/filepath"
 )
 
 func TestEnsureOverrides(t *testing.T) {
@@ -166,3 +167,38 @@ func TestEnsureUpdate(t *testing.T) {
 		}
 	}
 }
+
+func TestEnsureDryRun(t *testing.T) {
+	test.NeedsExternalNetwork(t)
+	test.NeedsGit(t)
+
+	h := test.NewHelper(t)
+	defer h.Cleanup()
+
+	// Setup up a test project
+	h.TempDir("src")
+	h.Setenv("GOPATH", h.Path("."))
+	h.TempCopy("src/thing/main.go", "ensure/update_main.go")
+	origManifest := "ensure/update_manifest.json"
+	h.TempCopy("src/thing/manifest.json", origManifest)
+	origLock := "ensure/update_lock.json"
+	h.TempCopy("src/thing/lock.json", origLock)
+	h.Cd(h.Path("src/thing"))
+
+	h.Run("ensure", "-n", "-update", "github.com/carolynvs/go-dep-test")
+
+	// Verify that nothing was modified during the dry-run
+	wantManifest := h.GetTestFileString(origManifest)
+	gotManifest := h.ReadManifest()
+	if gotManifest != wantManifest {
+		t.Fatalf("The manifest should not be modified during a dry-run. Expected %s, got %s", origManifest, gotManifest)
+	}
+
+	wantLock := h.GetTestFileString(origLock)
+	gotLock := h.ReadLock()
+	if gotLock != wantLock {
+		t.Fatalf("The lock should not be modified during a dry-run. Expected %s, got %s", origLock, gotLock)
+	}
+
+	h.MustNotExist(filepath.Join(h.Path("src/thing"), "vendor"))
+}