feat: add new functionality to create a graph from unchanged packages

This adds a function that creates a subgraph of only new
and changed package nodes in a graph.

src/core/create-changed-packages-graph.ts

@@ -0,0 +1,97 @@
+import { DepGraph, DepGraphInternal, NodeInfo, PkgInfo } from './types';
+import { DepGraphImpl } from './dep-graph';
+import { DepGraphBuilder } from './builder';
+import { eventLoopSpinner } from 'event-loop-spinner';
+
+type NodeId = string;
+
+/**
+ * Creates an induced subgraph of  {@param graphB} with only packages
+ * that are not present in {@param graphA} or have a different version.
+ *
+ * @param graphA
+ * @param graphB
+ */
+export async function createChangedPackagesGraph(
+  graphA: DepGraph,
+  graphB: DepGraph,
+): Promise<DepGraph> {
+  const depGraph = graphB as DepGraphInternal;
+
+  const graphAPackageIds = new Set(
+    graphA.getDepPkgs().map(DepGraphImpl.getPkgId),
+  );
+
+  const addedOrUpdatedPackages: PkgInfo[] = depGraph
+    .getDepPkgs()
+    .filter((pkg) => !graphAPackageIds.has(DepGraphImpl.getPkgId(pkg)));
+
+  const depGraphBuilder = new DepGraphBuilder(
+    depGraph.pkgManager,
+    depGraph.rootPkg,
+  );
+
+  const parentQueue: [parentId: NodeId, nodeId: NodeId][] = [];
+  for (const changedPackage of addedOrUpdatedPackages) {
+    for (const changedNodeId of depGraph.getPkgNodeIds(changedPackage)) {
+      //we add all nodes with new and changed packages to the new graph.
+      //a newly added node will also have its dependencies added here, since they are "new".
+      depGraphBuilder.addPkgNode(
+        depGraph.getNodePkg(changedNodeId),
+        changedNodeId,
+        getNodeInfo(depGraph, changedNodeId),
+      );
+
+      //Push all direct parents of the changed nodes to a queue to later build up a path to root from that node
+      for (const parentId of depGraph.getNodeParentsNodeIds(changedNodeId)) {
+        parentQueue.push([parentId, changedNodeId]);
+
+        if (eventLoopSpinner.isStarving()) {
+          await eventLoopSpinner.spin();
+        }
+      }
+    }
+  }
+
+  //add direct and transitive parents for the changed nodes
+  const visited = new Set([depGraph.rootNodeId]);
+
+  while (parentQueue.length > 0) {
+    const [nodeId, dependencyNodeId] = parentQueue.pop()!;
+    if (visited.has(nodeId)) {
+      //ensure we link parents even if visited through another path
+      depGraphBuilder.connectDep(nodeId, dependencyNodeId);
+      continue;
+    }
+
+    visited.add(nodeId);
+
+    depGraphBuilder.addPkgNode(
+      depGraph.getNodePkg(nodeId),
+      nodeId,
+      getNodeInfo(depGraph, nodeId),
+    );
+    depGraphBuilder.connectDep(nodeId, dependencyNodeId);
+
+    for (const parentId of depGraph.getNodeParentsNodeIds(nodeId)) {
+      parentQueue.push([parentId, nodeId]);
+
+      if (eventLoopSpinner.isStarving()) {
+        await eventLoopSpinner.spin();
+      }
+    }
+  }
+
+  return depGraphBuilder.build();
+}
+
+function getNodeInfo(
+  depGraph: DepGraphInternal,
+  nodeId: string,
+): NodeInfo | undefined {
+  const nodeInfo: NodeInfo = depGraph.getNode(nodeId);
+  if (!nodeInfo || Object.keys(nodeInfo).length === 0) {
+    return undefined;
+  }
+  return nodeInfo;
+}

src/core/dep-graph.ts

@@ -255,7 +255,7 @@ class DepGraphImpl implements types.DepGraphInternal {
     compareRoot: boolean,
     traversedPairs = new Set<string>(),
   ): boolean {
-    // Skip root nodes comparision if needed.
+    // Skip root nodes comparison if needed.
     if (
       compareRoot ||
       (nodeIdA !== graphA.rootNodeId && nodeIdB !== graphB.rootNodeId)

src/index.ts

@@ -8,9 +8,12 @@ export {
 } from './core/types';
 export { createFromJSON } from './core/create-from-json';
 export { DepGraphBuilder } from './core/builder';
+export { createChangedPackagesGraph } from './core/create-changed-packages-graph';
 
 import * as Errors from './core/errors';
+
 export { Errors };
 
 import * as legacy from './legacy';
+
 export { legacy };

test/core/create-changed-packages-graph.test.ts

@@ -0,0 +1,54 @@
+import * as depGraphLib from '../../src';
+import * as helpers from '../helpers';
+import { createChangedPackagesGraph } from '../../src';
+
+describe('filter-unchanged-packages', () => {
+  it.each`
+    fixture
+    ${'equals/simple.json'}
+    ${'cyclic-complex-dep-graph.json'}
+    ${'goof-graph.json'}
+  `(
+    'result and $fixture are equals for empty initial graph',
+    async ({ fixture }) => {
+      const graphB = depGraphLib.createFromJSON(helpers.loadFixture(fixture));
+
+      const graphA = new depGraphLib.DepGraphBuilder(
+        graphB.pkgManager,
+        graphB.rootPkg,
+      ).build();
+
+      const result = await createChangedPackagesGraph(graphA, graphB);
+      expect(graphB.equals(result)).toBe(true);
+    },
+  );
+
+  it.each`
+    fixtureA                               | fixtureB                                                                            | expected
+    ${'changed-packages-graph/graph.json'} | ${'changed-packages-graph/graph-direct-dep-added.json'}                             | ${'changed-packages-graph/graph-direct-dep-added-expected.json'}
+    ${'changed-packages-graph/graph.json'} | ${'changed-packages-graph/graph-direct-dep-changed-cycle.json'}                     | ${'changed-packages-graph/graph-direct-dep-changed-cycle-expected.json'}
+    ${'changed-packages-graph/graph.json'} | ${'changed-packages-graph/graph-direct-dep-changed.json'}                           | ${'changed-packages-graph/graph-direct-dep-changed-expected.json'}
+    ${'changed-packages-graph/graph.json'} | ${'changed-packages-graph/graph-direct-dep-removed.json'}                           | ${'changed-packages-graph/graph-direct-dep-removed-expected.json'}
+    ${'changed-packages-graph/graph.json'} | ${'changed-packages-graph/graph-direct-dep-with-exiting-transitive-dep-added.json'} | ${'changed-packages-graph/graph-direct-dep-with-exiting-transitive-dep-added-expected.json'}
+    ${'changed-packages-graph/graph.json'} | ${'changed-packages-graph/graph-root-and-direct-dep-changed.json'}                  | ${'changed-packages-graph/graph-root-and-direct-dep-changed-expected.json'}
+    ${'changed-packages-graph/graph.json'} | ${'changed-packages-graph/graph-root-changed-expected.json'}                        | ${'changed-packages-graph/graph-root-changed-expected.json'}
+    ${'changed-packages-graph/graph.json'} | ${'changed-packages-graph/graph-transitive-dep-as-direct-dep.json'}                 | ${'changed-packages-graph/graph-transitive-dep-as-direct-dep-expected.json'}
+    ${'changed-packages-graph/graph.json'} | ${'changed-packages-graph/graph-transitive-dep-changed-cycle.json'}                 | ${'changed-packages-graph/graph-transitive-dep-changed-cycle-expected.json'}
+    ${'changed-packages-graph/graph.json'} | ${'changed-packages-graph/graph-transitive-dep-changed.json'}                       | ${'changed-packages-graph/graph-transitive-dep-changed-expected.json'}
+    ${'changed-packages-graph/graph.json'} | ${'changed-packages-graph/graph-transitive-dep-removed.json'}                       | ${'changed-packages-graph/graph-transitive-dep-removed-expected.json'}
+  `(
+    'result is $expected for $fixtureA and $fixtureB',
+    async ({ fixtureA, fixtureB, expected }) => {
+      const graphA = depGraphLib.createFromJSON(helpers.loadFixture(fixtureA));
+
+      const graphB = depGraphLib.createFromJSON(helpers.loadFixture(fixtureB));
+
+      const expectedResult = depGraphLib.createFromJSON(
+        helpers.loadFixture(expected),
+      );
+
+      const result = await createChangedPackagesGraph(graphA, graphB);
+      expect(expectedResult.equals(result, { compareRoot: true })).toBe(true);
+    },
+  );
+});

test/fixtures/changed-packages-graph/graph-direct-dep-added-expected.json

@@ -0,0 +1,57 @@
+{
+  "schemaVersion": "1.3.0",
+  "pkgManager": {
+    "name": "pip"
+  },
+  "pkgs": [
+    {
+      "id": "a@1",
+      "info": {
+        "name": "a",
+        "version": "1"
+      }
+    },
+    {
+      "id": "[email protected]",
+      "info": {
+        "name": "l",
+        "version": "0.1"
+      }
+    },
+    {
+      "id": "[email protected]",
+      "info": {
+        "name": "m",
+        "version": "1.2"
+      }
+    }
+  ],
+  "graph": {
+    "rootNodeId": "root-node",
+    "nodes": [
+      {
+        "nodeId": "12",
+        "pkgId": "[email protected]",
+        "deps": [
+          {
+            "nodeId": "13"
+          }
+        ]
+      },
+      {
+        "nodeId": "13",
+        "pkgId": "[email protected]",
+        "deps": []
+      },
+      {
+        "nodeId": "root-node",
+        "pkgId": "a@1",
+        "deps": [
+          {
+            "nodeId": "12"
+          }
+        ]
+      }
+    ]
+  }
+}