From 9d9456442f82d8be2c80e9725359825cbdb26be9 Mon Sep 17 00:00:00 2001
From: Zoltan Kochan <z@kochan.io>
Date: Wed, 2 Sep 2020 16:47:18 +0300
Subject: [PATCH] perf: using pkgId as nodeId for leaf deps

---
 .changeset/mean-zoos-shout.md                 |  5 +++
 .../resolve-dependencies/src/nodeIdUtils.ts   |  1 +
 .../src/resolveDependencies.ts                | 31 +++++++++++++------
 3 files changed, 28 insertions(+), 9 deletions(-)
 create mode 100644 .changeset/mean-zoos-shout.md

diff --git a/.changeset/mean-zoos-shout.md b/.changeset/mean-zoos-shout.md
new file mode 100644
index 0000000000..076902da56
--- /dev/null
+++ b/.changeset/mean-zoos-shout.md
@@ -0,0 +1,5 @@
+---
+"@pnpm/resolve-dependencies": major
+---
+
+In case of leaf dependencies (dependencies that have no prod deps or peer deps), we only ever need to analyze one leaf dep in a graph, so the nodeId can be short and stateless, like the package ID.
diff --git a/packages/resolve-dependencies/src/nodeIdUtils.ts b/packages/resolve-dependencies/src/nodeIdUtils.ts
index a934181d74..7e451366ca 100644
--- a/packages/resolve-dependencies/src/nodeIdUtils.ts
+++ b/packages/resolve-dependencies/src/nodeIdUtils.ts
@@ -8,6 +8,7 @@ export function nodeIdContainsSequence (nodeId: string, pkgId1: string, pkgId2:
 }
 
 export function createNodeId (parentNodeId: string, pkgId: string) {
+  // using ">" as a separator because it will never be used inside a package ID
   return `${parentNodeId}${pkgId}>`
 }
 
diff --git a/packages/resolve-dependencies/src/resolveDependencies.ts b/packages/resolve-dependencies/src/resolveDependencies.ts
index 9fa510a91a..d5f8624632 100644
--- a/packages/resolve-dependencies/src/resolveDependencies.ts
+++ b/packages/resolve-dependencies/src/resolveDependencies.ts
@@ -677,8 +677,11 @@ async function resolveDependency (
     })
   }
 
-  // using colon as it will never be used inside a package ID
-  const nodeId = createNodeId(options.parentPkg.nodeId, pkgResponse.body.id)
+  // In case of leaf dependencies (dependencies that have no prod deps or peer deps),
+  // we only ever need to analyze one leaf dep in a graph, so the nodeId can be short and stateless.
+  const nodeId = pkgIsLeaf(pkg)
+    ? pkgResponse.body.id
+    : createNodeId(options.parentPkg.nodeId, pkgResponse.body.id)
 
   const currentIsInstallable = (
     ctx.force ||
@@ -732,13 +735,17 @@ async function resolveDependency (
     ctx.resolvedPackagesByPackageId[pkgResponse.body.id].dev = ctx.resolvedPackagesByPackageId[pkgResponse.body.id].dev || wantedDependency.dev
     ctx.resolvedPackagesByPackageId[pkgResponse.body.id].optional = ctx.resolvedPackagesByPackageId[pkgResponse.body.id].optional && wantedDependency.optional
 
-    ctx.pendingNodes.push({
-      alias: wantedDependency.alias || pkg.name,
-      depth: options.currentDepth,
-      installable,
-      nodeId,
-      resolvedPackage: ctx.resolvedPackagesByPackageId[pkgResponse.body.id],
-    })
+    if (ctx.dependenciesTree[nodeId]) {
+      ctx.dependenciesTree[nodeId].depth = Math.min(ctx.dependenciesTree[nodeId].depth, options.currentDepth)
+    } else {
+      ctx.pendingNodes.push({
+        alias: wantedDependency.alias || pkg.name,
+        depth: options.currentDepth,
+        installable,
+        nodeId,
+        resolvedPackage: ctx.resolvedPackagesByPackageId[pkgResponse.body.id],
+      })
+    }
   }
 
   return {
@@ -758,6 +765,12 @@ async function resolveDependency (
   }
 }
 
+function pkgIsLeaf (pkg: PackageManifest) {
+  return R.isEmpty(pkg.dependencies ?? {}) &&
+    R.isEmpty(pkg.optionalDependencies ?? {}) &&
+    R.isEmpty(pkg.peerDependencies ?? {})
+}
+
 function getResolvedPackage (
   options: {
     dependencyLockfile?: PackageSnapshot