bake: reject targets inside target blocks

bake/bake.go

@@ -413,6 +413,10 @@ func ParseFiles(files []File, defaults, vars map[string]string) (_ *Config, _ *h
 		pm = *res
 	}
 
+	if err := validateTargetGroups(hclFiles); err != nil {
+		return nil, nil, err
+	}
+
 	return &c, &pm, nil
 }
 
@@ -442,6 +446,36 @@ func ParseFile(dt []byte, fn string) (*Config, error) {
 	return c, err
 }
 
+func validateTargetGroups(files []*hcl.File) error {
+	schema := &hcl.BodySchema{
+		Blocks: []hcl.BlockHeaderSchema{
+			{Type: "target", LabelNames: []string{"name"}},
+		},
+	}
+	for _, f := range files {
+		content, _, diags := f.Body.PartialContent(schema)
+		if diags.HasErrors() {
+			return diags
+		}
+		for _, block := range content.Blocks {
+			attrs, diags := block.Body.JustAttributes()
+			if diags.HasErrors() {
+				return diags
+			}
+			if attr, ok := attrs["targets"]; ok {
+				return hcl.Diagnostics{&hcl.Diagnostic{
+					Severity: hcl.DiagError,
+					Summary:  "Unsupported argument",
+					Detail:   "The \"targets\" argument is not valid inside a target block; use a group block instead.",
+					Subject:  attr.NameRange.Ptr(),
+					Context:  attr.Range.Ptr(),
+				}}
+			}
+		}
+	}
+	return nil
+}
+
 type Config struct {
 	Groups  []*Group  `json:"group" hcl:"group,block" cty:"group"`
 	Targets []*Target `json:"target" hcl:"target,block" cty:"target"`

bake/hcl_test.go

@@ -188,6 +188,164 @@ func TestHCLWithUserDefinedFunctions(t *testing.T) {
 	require.Equal(t, ptrstr("124"), c.Targets[0].Args["buildno"])
 }
 
+func TestTargetDisallowsGroupTargetsAttribute(t *testing.T) {
+	t.Run("hcl", func(t *testing.T) {
+		dt := []byte(`
+			target "app" {
+				dockerfile = "app.Dockerfile"
+			}
+
+			target "db" {
+				dockerfile = "db.Dockerfile"
+			}
+
+			target "foo" {
+				targets = ["app", "db"]
+			}
+		`)
+
+		_, err := ParseFile(dt, "docker-bake.hcl")
+		require.Error(t, err)
+		require.ErrorContains(t, err, "Unsupported argument")
+		require.ErrorContains(t, err, "targets")
+		require.ErrorContains(t, err, "docker-bake.hcl")
+	})
+
+	t.Run("json", func(t *testing.T) {
+		dt := []byte(`{
+			"group": {
+				"default": {
+					"targets": ["foo"]
+				}
+			},
+			"target": {
+				"app": {
+					"dockerfile": "app.Dockerfile"
+				},
+				"db": {
+					"dockerfile": "db.Dockerfile"
+				},
+				"foo": {
+					"targets": ["app", "db"]
+				}
+			}
+		}`)
+
+		_, err := ParseFile(dt, "docker-bake.json")
+		require.Error(t, err)
+		require.ErrorContains(t, err, "Unsupported argument")
+		require.ErrorContains(t, err, "targets")
+		require.ErrorContains(t, err, "docker-bake.json")
+	})
+
+	t.Run("merged hcl files", func(t *testing.T) {
+		_, _, err := ParseFiles([]File{
+			{
+				Name: "base.hcl",
+				Data: []byte(`
+					target "app" {
+						dockerfile = "app.Dockerfile"
+					}
+
+					target "db" {
+						dockerfile = "db.Dockerfile"
+					}
+				`),
+			},
+			{
+				Name: "group-as-target.hcl",
+				Data: []byte(`
+					target "foo" {
+						targets = ["app", "db"]
+					}
+				`),
+			},
+		}, nil, nil)
+		require.Error(t, err)
+		require.ErrorContains(t, err, "Unsupported argument")
+		require.ErrorContains(t, err, "targets")
+		require.ErrorContains(t, err, "group-as-target.hcl")
+	})
+
+	t.Run("merged hcl and json", func(t *testing.T) {
+		_, _, err := ParseFiles([]File{
+			{
+				Name: "docker-bake.hcl",
+				Data: []byte(`
+					group "default" {
+						targets = ["foo"]
+					}
+
+					target "app" {
+						dockerfile = "app.Dockerfile"
+					}
+				`),
+			},
+			{
+				Name: "extra.json",
+				Data: []byte(`{
+					"target": {
+						"foo": {
+							"targets": ["app"]
+						}
+					}
+				}`),
+			},
+		}, nil, nil)
+		require.Error(t, err)
+		require.ErrorContains(t, err, "Unsupported argument")
+		require.ErrorContains(t, err, "targets")
+		require.ErrorContains(t, err, "extra.json")
+	})
+
+	t.Run("group targets still valid", func(t *testing.T) {
+		dt := []byte(`
+			target "app" {
+				dockerfile = "app.Dockerfile"
+			}
+
+			target "db" {
+				dockerfile = "db.Dockerfile"
+			}
+
+			group "foo" {
+				targets = ["app", "db"]
+			}
+		`)
+
+		c, err := ParseFile(dt, "docker-bake.hcl")
+		require.NoError(t, err)
+		require.Equal(t, 1, len(c.Groups))
+		require.Equal(t, "foo", c.Groups[0].Name)
+		require.Equal(t, []string{"app", "db"}, c.Groups[0].Targets)
+	})
+
+	t.Run("merged valid files", func(t *testing.T) {
+		c, _, err := ParseFiles([]File{
+			{
+				Name: "targets.hcl",
+				Data: []byte(`
+					target "app" {
+						dockerfile = "app.Dockerfile"
+					}
+				`),
+			},
+			{
+				Name: "groups.hcl",
+				Data: []byte(`
+					group "foo" {
+						targets = ["app"]
+					}
+				`),
+			},
+		}, nil, nil)
+		require.NoError(t, err)
+		require.Equal(t, 1, len(c.Groups))
+		require.Equal(t, "foo", c.Groups[0].Name)
+		require.Equal(t, []string{"app"}, c.Groups[0].Targets)
+	})
+}
+
 func TestHCLWithVariables(t *testing.T) {
 	dt := []byte(`
 		variable "BUILD_NUMBER" {