fix dockerfile local dir

Signed-off-by: Ye Sijun <junnplus@gmail.com>

cmd/nerdctl/build.go

@@ -327,7 +327,6 @@ func generateBuildctlArgs(cmd *cobra.Command, buildkitHost string, platform, arg
 		"--progress=" + progressValue,
 		"--frontend=dockerfile.v0",
 		"--local=context=" + buildContext,
-		"--local=dockerfile=" + buildContext,
 		"--output=" + output,
 	}...)
 
@@ -336,28 +335,35 @@ func generateBuildctlArgs(cmd *cobra.Command, buildkitHost string, platform, arg
 		return "", nil, false, "", nil, nil, err
 	}
 
-	var dir, file string
-
+	dir := buildContext
+	file := buildkitutil.DefaultDockerfileName
 	if filename != "" {
 		if filename == "-" {
 			var err error
 			dir, err = buildkitutil.WriteTempDockerfile(cmd.InOrStdin())
 			if err != nil {
 				return "", nil, false, "", nil, nil, err
 			}
-			file = buildkitutil.DefaultDockerfileName
 			cleanup = func() {
 				os.RemoveAll(dir)
 			}
 		} else {
 			dir, file = filepath.Split(filename)
 		}
 
-		if dir != "" {
-			buildctlArgs = append(buildctlArgs, "--local=dockerfile="+dir)
+		if dir == "" {
+			dir = "."
 		}
-		buildctlArgs = append(buildctlArgs, "--opt=filename="+file)
 	}
+	absDir, err := filepath.Abs(dir)
+	if err != nil {
+		return "", nil, false, "", nil, nil, err
+	}
+	if _, err := os.Lstat(filepath.Join(absDir, file)); err != nil {
+		return "", nil, false, "", nil, nil, err
+	}
+	buildctlArgs = append(buildctlArgs, "--local=dockerfile="+dir)
+	buildctlArgs = append(buildctlArgs, "--opt=filename="+file)
 
 	target, err := cmd.Flags().GetString("target")
 	if err != nil {

cmd/nerdctl/build_test.go

@@ -140,6 +140,38 @@ CMD ["echo", "nerdctl-build-test-stdin"]
 	base.Cmd("build", "-t", imageName, "-f", "-", ".").CmdOption(testutil.WithStdin(strings.NewReader(dockerfile))).AssertCombinedOutContains(imageName)
 }
 
+func TestBuildWithDockerfile(t *testing.T) {
+	testutil.RequiresBuild(t)
+	base := testutil.NewBase(t)
+	defer base.Cmd("builder", "prune").Run()
+	imageName := testutil.Identifier(t)
+	defer base.Cmd("rmi", imageName).Run()
+
+	dockerfile := fmt.Sprintf(`FROM %s
+CMD ["echo", "nerdctl-build-test-dockerfile"]
+	`, testutil.CommonImage)
+
+	buildCtx := filepath.Join(t.TempDir(), "test")
+	err := os.MkdirAll(buildCtx, 0755)
+	assert.NilError(t, err)
+	err = os.WriteFile(filepath.Join(buildCtx, "Dockerfile"), []byte(dockerfile), 0644)
+	assert.NilError(t, err)
+
+	pwd, err := os.Getwd()
+	assert.NilError(t, err)
+	err = os.Chdir(buildCtx)
+	assert.NilError(t, err)
+	defer os.Chdir(pwd)
+
+	// hack os.Getwd return "(unreachable)" on rootless
+	t.Setenv("PWD", buildCtx)
+
+	base.Cmd("build", "-t", imageName, "-f", "Dockerfile", "..").AssertOK()
+	base.Cmd("build", "-t", imageName, "-f", "Dockerfile", ".").AssertOK()
+	// fail err: no such file or directory
+	base.Cmd("build", "-t", imageName, "-f", "../Dockerfile", ".").AssertFail()
+}
+
 func TestBuildLocal(t *testing.T) {
 	t.Parallel()
 	testutil.DockerIncompatible(t)