Merge pull request #2174 from alixander/create-board-api-2

better detection of empty boards

d2compiler/compile.go

@@ -114,20 +114,21 @@ func (c *compiler) compileBoardsField(g *d2graph.Graph, ir *d2ir.Map, fieldName
 		return
 	}
 	for _, f := range boards.Map().Fields {
+		m := f.Map()
 		if f.Map() == nil {
-			continue
+			m = &d2ir.Map{}
 		}
 		if g.GetBoard(f.Name) != nil {
 			c.errorf(f.References[0].AST(), "board name %v already used by another board", f.Name)
 			continue
 		}
 		g2 := d2graph.NewGraph()
 		g2.Parent = g
-		g2.AST = f.Map().AST().(*d2ast.Map)
+		g2.AST = m.AST().(*d2ast.Map)
 		if g.BaseAST != nil {
 			g2.BaseAST = findFieldAST(g.BaseAST, f)
 		}
-		c.compileBoard(g2, f.Map())
+		c.compileBoard(g2, m)
 		g2.Name = f.Name
 		switch fieldName {
 		case "layers":

d2oracle/edit_test.go

@@ -543,6 +543,27 @@ layers: {
     }
   }
 }
+`,
+		},
+		{
+			name: "add_layer/4",
+			text: `b
+
+layers: {
+	c
+}
+`,
+			key: `d`,
+
+			boardPath: []string{"c"},
+			expKey:    `d`,
+			exp: `b
+
+layers: {
+  c: {
+    d
+  }
+}
 `,
 		},
 		{