Add multiple entrypoint support to the dependency traversal logic

Reviewed By: davidaurelio

Differential Revision: D7180692

fbshipit-source-id: 65b1992abbf10e753b6895623824ff90d7cadc24

packages/metro/src/DeltaBundler/DeltaCalculator.js

@@ -12,7 +12,7 @@
 
 const {
   initialTraverseDependencies,
-  reorderDependencies,
+  reorderGraph,
   traverseDependencies,
 } = require('./traverseDependencies');
 const {EventEmitter} = require('events');
@@ -60,13 +60,15 @@ class DeltaCalculator extends EventEmitter {
     this._options = options;
     this._dependencyGraph = dependencyGraph;
 
-    const entryFilePath = this._dependencyGraph.getAbsolutePath(
-      this._options.entryFile,
-    );
+    // The traverse dependencies logic supports multiple entry points, but
+    // currently metro only supports to pass a single entry point when bundling.
+    const entryPoints = [
+      this._dependencyGraph.getAbsolutePath(this._options.entryFile),
+    ];
 
     this._graph = {
       dependencies: new Map(),
-      entryFile: entryFilePath,
+      entryPoints,
     };
 
     this._dependencyGraph
@@ -87,7 +89,7 @@ class DeltaCalculator extends EventEmitter {
     // Clean up all the cache data structures to deallocate memory.
     this._graph = {
       dependencies: new Map(),
-      entryFile: this._options.entryFile,
+      entryPoints: [this._options.entryFile],
     };
     this._modifiedFiles = new Set();
     this._deletedFiles = new Set();
@@ -148,10 +150,7 @@ class DeltaCalculator extends EventEmitter {
 
     // Return all the modules if the client requested a reset delta.
     if (reset) {
-      this._graph.dependencies = reorderDependencies(
-        this._graph.dependencies.get(this._graph.entryFile),
-        this._graph.dependencies,
-      );
+      reorderGraph(this._graph);
 
       return {
         modified: this._graph.dependencies,
@@ -202,7 +201,7 @@ class DeltaCalculator extends EventEmitter {
         const {added} = await initialTraverseDependencies(
           {
             dependencies: new Map(),
-            entryFile: path,
+            entryPoints: [path],
           },
           this._dependencyGraph,
           transformOptionsForBlacklist,

packages/metro/src/DeltaBundler/__tests__/DeltaCalculator-test.js

@@ -15,7 +15,6 @@ jest.mock('../traverseDependencies');
 
 const {
   initialTraverseDependencies,
-  reorderDependencies,
   traverseDependencies,
 } = require('../traverseDependencies');
 
@@ -198,8 +197,6 @@ describe('DeltaCalculator', () => {
   });
 
   it('should return a full delta when passing reset=true', async () => {
-    reorderDependencies.mockImplementation((_, edges) => edges);
-
     await deltaCalculator.getDelta({reset: false});
 
     const result = await deltaCalculator.getDelta({reset: true});

packages/metro/src/DeltaBundler/__tests__/__snapshots__/traverseDependencies-test.js.snap

@@ -59,6 +59,8 @@ Object {
       "path": "/baz",
     },
   },
-  "entryFile": "/bundle",
+  "entryPoints": Array [
+    "/bundle",
+  ],
 }
 `;

packages/metro/src/DeltaBundler/__tests__/traverseDependencies-integration-test.js

@@ -62,7 +62,7 @@ describe('traverseDependencies', function() {
 
     const graph = {
       dependencies: new Map(),
-      entryFile: entryPath,
+      entryPoints: [entryPath],
     };
 
     const {added} = await traverseDependencies.initialTraverseDependencies(
@@ -5073,7 +5073,7 @@ describe('traverseDependencies', function() {
       return traverseDependencies.initialTraverseDependencies(
         {
           dependencies: new Map(),
-          entryFile: '/root/index.js',
+          entryPoints: ['/root/index.js'],
         },
         dependencyGraph,
         emptyTransformOptions,

packages/metro/src/DeltaBundler/__tests__/traverseDependencies-test.js

@@ -12,6 +12,7 @@
 
 const {
   initialTraverseDependencies,
+  reorderGraph,
   traverseDependencies,
 } = require('../traverseDependencies');
 
@@ -172,7 +173,7 @@ beforeEach(async () => {
 
   graph = {
     dependencies: new Map(),
-    entryFile: '/bundle',
+    entryPoints: ['/bundle'],
   };
 });
 
@@ -377,6 +378,33 @@ describe('edge cases', () => {
     ]);
   });
 
+  it('should traverse a graph from multiple entry points', async () => {
+    entryModule = Actions.createFile('/bundle-2');
+
+    Actions.addDependency('/bundle-2', '/bundle-2-foo');
+    Actions.addDependency('/bundle-2', '/bundle-2-bar');
+    Actions.addDependency('/bundle-2', '/bar');
+
+    files = new Set();
+
+    graph = {
+      dependencies: new Map(),
+      entryPoints: ['/bundle', '/bundle-2'],
+    };
+
+    await initialTraverseDependencies(graph, dependencyGraph, {});
+
+    expect([...graph.dependencies.keys()]).toEqual([
+      '/bundle',
+      '/foo',
+      '/bar',
+      '/baz',
+      '/bundle-2',
+      '/bundle-2-foo',
+      '/bundle-2-bar',
+    ]);
+  });
+
   it('should traverse the dependency tree in a deterministic order', async () => {
     // Mocks the shallow dependency call, always resolving the module in
     // `slowPath` after the module in `fastPath`.
@@ -416,7 +444,7 @@ describe('edge cases', () => {
     async function assertOrder() {
       graph = {
         dependencies: new Map(),
-        entryFile: '/bundle',
+        entryPoints: ['/bundle'],
       };
 
       expect(
@@ -483,3 +511,33 @@ describe('edge cases', () => {
     expect(moduleFoo.read).toHaveBeenCalledWith({inlineRequires: true});
   });
 });
+
+describe('reorderGraph', () => {
+  it('should reorder any unordered graph in DFS order', async () => {
+    const graph = {
+      dependencies: new Map([
+        ['/2', {dependencies: new Map(), path: '/2'}],
+        [
+          '/0',
+          {path: '/0', dependencies: new Map([['/1', '/1'], ['/2', '/2']])},
+        ],
+        ['/1', {dependencies: new Map([['/2', '/2']]), path: '/1'}],
+        ['/3', {dependencies: new Map(), path: '/3'}],
+        ['/b', {dependencies: new Map([['/3', '/3']]), path: '/b'}],
+        ['/a', {dependencies: new Map([['/0', '/0']]), path: '/a'}],
+      ]),
+      entryPoints: ['/a', '/b'],
+    };
+
+    reorderGraph(graph);
+
+    expect([...graph.dependencies.keys()]).toEqual([
+      '/a',
+      '/0',
+      '/1',
+      '/2',
+      '/b',
+      '/3',
+    ]);
+  });
+});

packages/metro/src/DeltaBundler/traverseDependencies.js

@@ -35,7 +35,7 @@ export type DependencyEdges = Map<string, DependencyEdge>;
 
 export type Graph = {|
   dependencies: DependencyEdges,
-  entryFile: string,
+  entryPoints: $ReadOnlyArray<string>,
 |};
 
 type Result = {added: Map<string, DependencyEdge>, deleted: Set<string>};
@@ -67,7 +67,7 @@ type Delta = {
  * since the last traversal.
  */
 async function traverseDependencies(
-  paths: Array<string>,
+  paths: $ReadOnlyArray<string>,
   dependencyGraph: DependencyGraph,
   transformOptions: JSTransformerOptions,
   graph: Graph,
@@ -139,29 +139,23 @@ async function initialTraverseDependencies(
   transformOptions: JSTransformerOptions,
   onProgress?: (numProcessed: number, total: number) => mixed = () => {},
 ): Promise<Result> {
-  const edge = createEdge(
-    dependencyGraph.getModuleForPath(graph.entryFile),
-    graph,
+  graph.entryPoints.forEach(entryPoint =>
+    createEdge(dependencyGraph.getModuleForPath(entryPoint), graph),
   );
 
-  const delta = {
-    added: new Map([[edge.path, edge]]),
-    modified: new Map(),
-    deleted: new Set(),
-  };
-
-  await traverseDependenciesForSingleFile(
-    edge,
+  await traverseDependencies(
+    graph.entryPoints,
     dependencyGraph,
     transformOptions,
     graph,
-    delta,
     onProgress,
   );
 
+  reorderGraph(graph);
+
   return {
-    added: reorderDependencies(edge, delta.added),
-    deleted: delta.deleted,
+    added: graph.dependencies,
+    deleted: new Set(),
   };
 }
 
@@ -391,30 +385,37 @@ function resolveDependencies(
 
 /**
  * Retraverse the dependency graph in DFS order to reorder the modules and
- * guarantee the same order between runs.
+ * guarantee the same order between runs. This method mutates the passed graph.
  */
+function reorderGraph(graph: Graph) {
+  const parent = {
+    dependencies: new Map(graph.entryPoints.map(e => [e, e])),
+  };
+
+  const dependencies = reorderDependencies(parent, graph.dependencies);
+
+  graph.dependencies = dependencies;
+}
+
 function reorderDependencies(
-  edge: ?DependencyEdge,
+  edge: {|dependencies: Map<string, string>|} | DependencyEdge,
   dependencies: Map<string, DependencyEdge>,
   orderedDependencies?: Map<string, DependencyEdge> = new Map(),
 ): Map<string, DependencyEdge> {
-  if (
-    !edge ||
-    !dependencies.has(edge.path) ||
-    orderedDependencies.has(edge.path)
-  ) {
-    return orderedDependencies;
+  if (edge.path) {
+    if (orderedDependencies.has(edge.path)) {
+      return orderedDependencies;
+    }
+
+    orderedDependencies.set(edge.path, edge);
   }
 
-  orderedDependencies.set(edge.path, edge);
-
-  edge.dependencies.forEach(path =>
-    reorderDependencies(
-      dependencies.get(path),
-      dependencies,
-      orderedDependencies,
-    ),
-  );
+  edge.dependencies.forEach(path => {
+    const dep = dependencies.get(path);
+    if (dep) {
+      reorderDependencies(dep, dependencies, orderedDependencies);
+    }
+  });
 
   return orderedDependencies;
 }
@@ -422,5 +423,5 @@ function reorderDependencies(
 module.exports = {
   initialTraverseDependencies,
   traverseDependencies,
-  reorderDependencies,
+  reorderGraph,
 };