check for plugin feature errors in e2e tests

d2plugin/plugin_features.go

@@ -55,6 +55,16 @@ func FeatureSupportCheck(info *PluginInfo, g *d2graph.Graph) error {
 	}
 	if _, ok := featureMap[DESCENDANT_EDGES]; !ok {
 		for _, e := range g.Edges {
+			// descendant edges are ok in sequence diagrams
+			if e.Src.OuterSequenceDiagram() != nil || e.Dst.OuterSequenceDiagram() != nil {
+				continue
+			}
+			if !e.Src.IsContainer() && !e.Dst.IsContainer() {
+				continue
+			}
+			if e.Src == e.Dst {
+				return fmt.Errorf(`Connection "%s" is a self loop on a container, but layout engine "%s" does not support this.`, e.AbsID(), info.Name)
+			}
 			if e.Src.IsDescendantOf(e.Dst) || e.Dst.IsDescendantOf(e.Src) {
 				return fmt.Errorf(`Connection "%s" goes from a container to a descendant, but layout engine "%s" does not support this.`, e.AbsID(), info.Name)
 			}

e2etests/e2e_test.go

@@ -24,6 +24,7 @@ import (
 	"oss.terrastruct.com/d2/d2layouts/d2near"
 	"oss.terrastruct.com/d2/d2layouts/d2sequence"
 	"oss.terrastruct.com/d2/d2lib"
+	"oss.terrastruct.com/d2/d2plugin"
 	"oss.terrastruct.com/d2/d2renderers/d2svg"
 	"oss.terrastruct.com/d2/d2target"
 	"oss.terrastruct.com/d2/lib/log"
@@ -78,6 +79,8 @@ type testCase struct {
 	mtexts            []*d2target.MText
 	assertions        func(t *testing.T, diagram *d2target.Diagram)
 	skip              bool
+	dagreFeatureError string
+	elkFeatureError   string
 	expErr            string
 }
 
@@ -136,16 +139,20 @@ func run(t *testing.T, tc testCase) {
 
 	for _, layoutName := range layoutsTested {
 		var layout func(context.Context, *d2graph.Graph) error
+		var plugin d2plugin.Plugin
 		if layoutName == "dagre" {
 			layout = d2dagrelayout.DefaultLayout
+			plugin = &d2plugin.DagrePlugin
 		} else if layoutName == "elk" {
 			// If measured texts exists, we are specifically exercising text measurements, no need to run on both layouts
 			if tc.mtexts != nil {
 				continue
 			}
 			layout = d2elklayout.DefaultLayout
+			plugin = &d2plugin.ELKPlugin
 		}
-		diagram, _, err := d2lib.Compile(ctx, tc.script, &d2lib.CompileOptions{
+
+		diagram, g, err := d2lib.Compile(ctx, tc.script, &d2lib.CompileOptions{
 			Ruler:         ruler,
 			MeasuredTexts: tc.mtexts,
 			ThemeID:       0,
@@ -160,6 +167,26 @@ func run(t *testing.T, tc testCase) {
 			assert.Success(t, err)
 		}
 
+		pluginInfo, err := plugin.Info(ctx)
+		assert.Success(t, err)
+
+		err = d2plugin.FeatureSupportCheck(pluginInfo, g)
+		switch layoutName {
+		case "dagre":
+			if tc.dagreFeatureError != "" {
+				assert.Error(t, err)
+				assert.ErrorString(t, err, tc.dagreFeatureError)
+				return
+			}
+		case "elk":
+			if tc.elkFeatureError != "" {
+				assert.Error(t, err)
+				assert.ErrorString(t, err, tc.elkFeatureError)
+				return
+			}
+		}
+		assert.Success(t, err)
+
 		if tc.assertions != nil {
 			t.Run("assertions", func(t *testing.T) {
 				tc.assertions(t, diagram)

e2etests/stable_test.go

@@ -448,6 +448,7 @@ eee.shape: document
 eee <- aaa.ccc
 (eee <- aaa.ccc)[0]: '222'
 `,
+			dagreFeatureError: `Connection "(aaa.ccc -- aaa)[0]" goes from a container to a descendant, but layout engine "dagre" does not support this.`,
 		},
 		{
 			name: "chaos2",
@@ -1792,6 +1793,7 @@ c: {
   a
 }
 `,
+			dagreFeatureError: `Object "a" has attribute "width" and/or "height" set, but layout engine "dagre" does not support dimensions set on containers.`,
 		},
 		{
 			name: "crow_foot_arrowhead",

e2etests/todo_test.go

@@ -14,12 +14,14 @@ func testTodo(t *testing.T) {
 container.first -> container.second: 1->2
 container -> container.second: c->2
 `,
+			dagreFeatureError: `Connection "(container -> container.second)[0]" goes from a container to a descendant, but layout engine "dagre" does not support this.`,
 		},
 		{
 			name: "child_parent_edges",
 			script: `a.b -> a
 a.b -> a.b.c
 a.b.c.d -> a.b`,
+			dagreFeatureError: `Connection "(a.b -> a)[0]" goes from a container to a descendant, but layout engine "dagre" does not support this.`,
 		},
 		{
 			name: "container_label_loop",
@@ -27,6 +29,7 @@ a.b.c.d -> a.b`,
   b -> c
 }
 a -> a`,
+			dagreFeatureError: `Connection "(a -> a)[0]" is a self loop on a container, but layout engine "dagre" does not support this.`,
 		},
 		{
 			// as nesting gets deeper, the groups advance towards `c` and may overlap its lifeline