Merge pull request #772 from stealjs/circular

Fail the build if circular dependencies are found

lib/slim/checks/circular_dependencies.js

@@ -0,0 +1,40 @@
+var some = require("lodash/some");
+var values = require("lodash/values");
+var includes = require("lodash/includes");
+
+/**
+ * Checks whether there are circular dependencies in the graph
+ * @param {Object} steal - The dependency graph object
+ * @throws if circular dependencies are found
+ */
+module.exports = function(graph) {
+	var nodes = values(graph);
+
+	if (some(nodes, hasCircularDependencies)) {
+		throw new Error(
+			`Cannot create slim build. Circular dependencies are not supported`
+		);
+	}
+};
+
+/**
+ * Whether the node has a circular dependency
+ * @param {Object} - A node from the dependency graph
+ * @param {number} - The index of the node in the (array) graph
+ * @param {Array.[Object]} - A list of nodes
+ * @return `true` if a circular dependency is found
+ */
+function hasCircularDependencies(node, index, nodes) {
+	for (var i = index + 1; i < nodes.length; i += 1) {
+		var nextNode = nodes[i];
+
+		if (
+			includes(node.dependencies, nextNode.load.name) &&
+			includes(nextNode.dependencies, node.load.name)
+		) {
+			return true;
+		}
+	}
+
+	return false;
+}

lib/stream/check_slim_support.js

@@ -4,6 +4,7 @@ var through = require("through2");
 var checkStealAndLoader = require("../slim/checks/steal_and_loader");
 var checkStealConditional = require("../slim/checks/steal_conditional");
 var checkProductionEnvConfig = require("../slim/checks/production_env_config");
+var checkCircularDependencies = require("../slim/checks/circular_dependencies");
 
 module.exports = function() {
 	return through.obj(function(data, enc, done) {
@@ -21,6 +22,7 @@ function checkSupport(data) {
 	checkStealAndLoader(configMain, data.graph);
 	checkStealConditional(data.graph[configMain]);
 	checkProductionEnvConfig(data.steal);
+	checkCircularDependencies(data.graph);
 
 	return data;
 }

test/slim_build_test.js

@@ -267,10 +267,14 @@ describe("slim builds", function() {
 				return Promise.all([args.close, find(args.browser, "_props")]);
 			})
 			.then(function(data) {
-				assert.deepEqual(data[1], {
-					foo: "foo",
-					bar: "bar"
-				}, "module cache works");
+				assert.deepEqual(
+					data[1],
+					{
+						foo: "foo",
+						bar: "bar"
+					},
+					"module cache works"
+				);
 				data[0]();
 			});
 	});
@@ -336,4 +340,21 @@ describe("slim builds", function() {
 				data[0]();
 			});
 	});
+
+	it("errors out with circular dependencies", function(done) {
+		var base = path.join(__dirname, "circular");
+		var config = { config: path.join(base, "package.json!npm") };
+
+		rmdir(path.join(base, "dist"))
+			.then(function() {
+				return optimize(config, { minify: false, quiet: true });
+			})
+			.then(function() {
+				done(new Error("should not build the app"));
+			})
+			.catch(function(err) {
+				assert(/Cannot create slim build/.test(err.message));
+				done();
+			});
+	});
 });