[v2]stop with an error immediately if a file or directory with that name already exists (#7188)

* fix #7182

Signed-off-by: zwwhdls <zwwhdls@hotmail.com>

* fix typo

Signed-off-by: zwwhdls <zwwhdls@hotmail.com>

* add testcase

Signed-off-by: zwwhdls <zwwhdls@hotmail.com>

* fix conflict subdirectory when untardir is the clashing directory

Signed-off-by: zwwhdls <zwwhdls@hotmail.com>

cmd/helm/fetch.go

@@ -166,13 +166,20 @@ func (f *fetchCmd) run() error {
 		if !filepath.IsAbs(ud) {
 			ud = filepath.Join(f.destdir, ud)
 		}
-		if fi, err := os.Stat(ud); err != nil {
-			if err := os.MkdirAll(ud, 0755); err != nil {
+		// Let udCheck to check conflict file/dir without replacing ud when untarDir is the current directory(.).
+		udCheck := ud
+		if udCheck == "." {
+			_, udCheck = filepath.Split(f.chartRef)
+		} else {
+			_, chartName := filepath.Split(f.chartRef)
+			udCheck = filepath.Join(udCheck, chartName)
+		}
+		if _, err := os.Stat(udCheck); err != nil {
+			if err := os.MkdirAll(udCheck, 0755); err != nil {
 				return fmt.Errorf("Failed to untar (mkdir): %s", err)
 			}
-
-		} else if !fi.IsDir() {
-			return fmt.Errorf("Failed to untar: %s is not a directory", ud)
+		} else {
+			return fmt.Errorf("Failed to untar: a file or directory with the name %s already exists", udCheck)
 		}
 
 		return chartutil.ExpandFile(ud, saved)

cmd/helm/fetch_test.go

@@ -22,6 +22,7 @@ import (
 	"os"
 	"path/filepath"
 	"regexp"
+	"strings"
 	"testing"
 
 	"k8s.io/helm/pkg/repo/repotest"
@@ -48,6 +49,9 @@ func TestFetchCmd(t *testing.T) {
 		chart        string
 		flags        []string
 		fail         bool
+		wantErrorMsg string
+		existFile    string
+		existDir     string
 		failExpect   string
 		expectFile   string
 		expectDir    bool
@@ -98,13 +102,29 @@ func TestFetchCmd(t *testing.T) {
 			expectFile: "./signtest",
 			expectDir:  true,
 		},
+		{
+			name:         "Fetch untar when file with same name existed",
+			flags:        []string{"test/test1 --untar --untardir test1"},
+			existFile:    "test1",
+			fail:         true,
+			wantErrorMsg: "failed to untar",
+		},
+		{
+			name:         "Fetch untar when dir with same name existed",
+			flags:        []string{"test/test2 --untar --untardir test2"},
+			existDir:     "test2",
+			fail:         true,
+			wantErrorMsg: "failed to untar",
+		},
 		{
 			name:         "Fetch, verify, untar",
 			chart:        "test/signtest",
-			flags:        []string{"--verify", "--keyring", "testdata/helm-test-key.pub", "--untar", "--untardir", "signtest"},
-			expectFile:   "./signtest",
+			flags:        []string{"--verify", "--keyring", "testdata/helm-test-key.pub", "--untar", "--untardir", "signtest2"},
+			expectFile:   "./signtest2",
 			expectDir:    true,
 			expectVerify: true,
+			failExpect:   "Failed to untar signtest",
+			fail:         true,
 		},
 		{
 			name:       "Chart fetch using repo URL",
@@ -146,13 +166,31 @@ func TestFetchCmd(t *testing.T) {
 		os.RemoveAll(outdir)
 		os.Mkdir(outdir, 0755)
 
+		// Create file or Dir before helm pull --untar, see: https://github.com/helm/helm/issues/7182
+		if tt.existFile != "" {
+			file := filepath.Join(outdir, tt.existFile)
+			_, err := os.Create(file)
+			if err != nil {
+				t.Fatal("err")
+			}
+		}
+		if tt.existDir != "" {
+			file := filepath.Join(outdir, tt.existDir)
+			err := os.Mkdir(file, 0755)
+			if err != nil {
+				t.Fatal(err)
+			}
+		}
 		buf := bytes.NewBuffer(nil)
 		cmd := newFetchCmd(buf)
 		tt.flags = append(tt.flags, "-d", outdir)
 		cmd.ParseFlags(tt.flags)
 		if err := cmd.RunE(cmd, []string{tt.chart}); err != nil {
 			if tt.fail {
-				continue
+				if tt.wantErrorMsg != "" && strings.Contains(tt.wantErrorMsg, err.Error()) {
+					t.Fatalf("Actual error %s, not equal to expected error %s", err, tt.wantErrorMsg)
+				}
+				return
 			}
 			t.Errorf("%q reported error: %s", tt.name, err)
 			continue