feat(externals): smartly pick latest version and warn only on two dif…

…ferent major

package.json

@@ -78,6 +78,7 @@
     "rollup-plugin-terser": "^7.0.2",
     "rollup-plugin-visualizer": "^5.6.0",
     "scule": "^0.2.1",
+    "semver": "^7.3.5",
     "serve-placeholder": "^1.2.4",
     "serve-static": "^1.14.2",
     "std-env": "^3.0.1",
@@ -93,6 +94,7 @@
     "@types/fs-extra": "^9.0.13",
     "@types/http-proxy": "^1.17.8",
     "@types/node-fetch": "^2.6.1",
+    "@types/semver": "^7.3.9",
     "@types/serve-static": "^1.13.10",
     "c8": "^7.11.0",
     "eslint": "^8.11.0",

src/rollup/plugins/externals.ts

@@ -3,6 +3,7 @@ import { resolve, dirname, normalize, join, isAbsolute } from 'pathe'
 import { nodeFileTrace, NodeFileTraceOptions } from '@vercel/nft'
 import type { Plugin } from 'rollup'
 import { resolvePath, isValidNodeImport } from 'mlly'
+import semver from 'semver'
 
 export interface NodeExternalsOptions {
   inline?: string[]
@@ -142,6 +143,17 @@ export function externals (opts: NodeExternalsOptions): Plugin {
         .then(r => Array.from(r.fileList).map(f => resolve(opts.traceOptions.base, f)))
         .then(r => r.filter(file => file.includes('node_modules')))
 
+      // Read package.json with cache
+      const packageJSONCache = new Map() // pkgDir => contents
+      const getPackageJson = async (pkgDir: string) => {
+        if (packageJSONCache.has(pkgDir)) {
+          return packageJSONCache.get(pkgDir)
+        }
+        const pkgJSON = JSON.parse(await fsp.readFile(resolve(pkgDir, 'package.json'), 'utf8'))
+        packageJSONCache.set(pkgDir, pkgJSON)
+        return pkgJSON
+      }
+
       // Keep track of npm packages
       const tracedPackages = new Map() // name => pkgDir
       for (const file of tracedFiles) {
@@ -151,13 +163,19 @@ export function externals (opts: NodeExternalsOptions): Plugin {
         // Check for duplicate versions
         const existingPkgDir = tracedPackages.get(pkgName)
         if (existingPkgDir && existingPkgDir !== pkgDir) {
-          console.warn(`Multiple versions of package ${pkgName} detected in:\n` + [
-            existingPkgDir,
-            pkgDir
-          ].map(p => '  - ' + p).join('\n'))
-          continue
+          const v1 = await getPackageJson(existingPkgDir).then(r => r.version)
+          const v2 = await getPackageJson(pkgDir).then(r => r.version)
+          if (semver.gte(v1, v2)) {
+            // Existing record is newer or same. Just skip.
+            continue
+          }
+          if (semver.major(v1) !== semver.major(v2)) {
+            console.warn(`Multiple major versions of package ${pkgName} are being externalized. Picking latest version.\n` + [
+              existingPkgDir + '@' + v1,
+              pkgDir + '@' + v2
+            ].map(p => '  - ' + p).join('\n'))
+          }
         }
-
         // Add to traced packages
         tracedPackages.set(pkgName, pkgDir)
       }

yarn.lock

@@ -889,6 +889,13 @@ __metadata:
   languageName: node
   linkType: hard
 
+"@types/semver@npm:^7.3.9":
+  version: 7.3.9
+  resolution: "@types/semver@npm:7.3.9"
+  checksum: 60bfcfdfa7f937be2c6f4b37ddb6714fb0f27b05fe4cbdfdd596a97d35ed95d13ee410efdd88e72a66449d0384220bf20055ab7d6b5df10de4990fbd20e5cbe0
+  languageName: node
+  linkType: hard
+
 "@types/serve-static@npm:^1.13.10":
   version: 1.13.10
   resolution: "@types/serve-static@npm:1.13.10"
@@ -5099,6 +5106,7 @@ __metadata:
     "@types/http-proxy": ^1.17.8
     "@types/jsdom": ^16.2.14
     "@types/node-fetch": ^2.6.1
+    "@types/semver": ^7.3.9
     "@types/serve-static": ^1.13.10
     "@vercel/nft": ^0.17.5
     archiver: ^5.3.0
@@ -5141,6 +5149,7 @@ __metadata:
     rollup-plugin-terser: ^7.0.2
     rollup-plugin-visualizer: ^5.6.0
     scule: ^0.2.1
+    semver: ^7.3.5
     serve-placeholder: ^1.2.4
     serve-static: ^1.14.2
     std-env: ^3.0.1