feat: add record default registry option

Create shrinkwrap files with resolved urls modified to replace the
configured registry with the default registry,
https://registry.npmjs.org.

The default registry is a magic value meaning the current registry, so
recording resolved with the default registry allows users to switch to a
different registry without removing their lockfile. The path portion of
the acutal resolved url is preserved so this trick only works when the
different registries host tarballs at the same relative paths. It's
faster than the omitLockfileRegistryResolved option because npm doesn't
need to fetch each pacument to resolve the tarball url.

workspaces/arborist/lib/override-resolves.js

@@ -1,10 +1,51 @@
-function overrideResolves (resolved, opts = {}) {
-  const { omitLockfileRegistryResolved = false } = opts
+const npa = require('npm-package-arg')
 
-  if (omitLockfileRegistryResolved) {
+function overrideResolves (node, resolved, opts = {}) {
+  const {
+    omitLockfileRegistryResolved = false,
+    recordDefaultRegistry = false,
+  } = opts
+
+  const isRegistryDependency = node.isRegistryDependency
+
+  // omit the resolved url of registry dependencies. this makes installs slower
+  // because npm must resolve the url for each package version but it allows
+  // users to use a lockfile across registries that host tarballs at different
+  // paths.
+  if (isRegistryDependency && omitLockfileRegistryResolved) {
     return undefined
   }
 
+  // replace the configured registry with the default registry. the default
+  // registry is a magic value meaning the current registry, so recording
+  // resolved with the default registry allows users to switch to a
+  // different registry without removing their lockfile. The path portion
+  // of the resolved url is preserved so this trick only works when the
+  // different registries host tarballs at the same relative paths.
+  if (isRegistryDependency && recordDefaultRegistry) {
+    const scope = npa(node.packageName).scope
+    const registry = scope && opts[`${scope}:registry`]
+      ? opts[`${scope}:registry`]
+      : opts.registry
+
+    // normalize registry url - strip trailing slash.
+    // TODO improve normalization for both the configured registry and resolved
+    // url. consider port, protocol, more path normalization.
+    const normalized = registry.endsWith('/')
+      ? registry.slice(0, -1)
+      : registry
+
+    // only replace the host if the resolved url is for the configured
+    // registry. registries may host tarballs on another server. return
+    // undefined so npm will re-resolve the url from the current registry when
+    // it reads the lockfile.
+    if (resolved.startsWith(normalized)) {
+      return 'https://registry.npmjs.org' + resolved.slice(normalized.length)
+    } else {
+      return undefined
+    }
+  }
+
   return resolved
 }
 

workspaces/arborist/lib/shrinkwrap.js

@@ -300,13 +300,8 @@ class Shrinkwrap {
     })
 
     const resolved = consistentResolve(node.resolved, node.path, path, true)
-    // hide resolved from registry dependencies.
-    if (!resolved) {
-      // no-op
-    } else if (node.isRegistryDependency) {
-      meta.resolved = overrideResolves(resolved, options)
-    } else {
-      meta.resolved = resolved
+    if (resolved) {
+      meta.resolved = overrideResolves(node, resolved, options)
     }
 
     if (node.extraneous) {
@@ -1027,7 +1022,7 @@ class Shrinkwrap {
         spec.type !== 'git' &&
         spec.type !== 'file' &&
         spec.type !== 'remote') {
-      lock.resolved = overrideResolves(node.resolved, this.resolveOptions)
+      lock.resolved = overrideResolves(node, node.resolved, this.resolveOptions)
     }
 
     if (node.integrity) {

workspaces/arborist/test/shrinkwrap.js

@@ -247,7 +247,7 @@ t.only('resolveOptions', async t => {
         dependencies: {
           registry: '^1.0.0',
           'some-other-registry': '^1.0.0',
-          '@scoped/some-other-registry': '^1.0.0',
+          '@scope/some-package': '^1.0.0',
           tar: url,
         },
       },
@@ -271,7 +271,7 @@ t.only('resolveOptions', async t => {
     })
 
     const scopedOtherRegistry = new Node({
-      pkg: { name: '@scope/some-other-registry', version: '1.2.3' },
+      pkg: { name: '@scope/some-package', version: '1.2.3' },
       resolved: someOtherRegistry,
       integrity: 'sha512-registry',
       parent: root,
@@ -312,6 +312,33 @@ t.only('resolveOptions', async t => {
     t.strictSame(data.dependencies.tar.resolved, undefined)
   })
 
+  await t.test('recordDefaultRegistry: true', async t => {
+    const { data } = await getData({
+      recordDefaultRegistry: true,
+      registry: 'https://private.registry.org/deadbeef',
+      '@scope:registry': 'https://someother.registry.org',
+    })
+
+    // unscoped packages that resolve to their configured registry should be
+    // record the default registry
+    t.strictSame(data.packages['node_modules/registry'].resolved,
+      'https://registry.npmjs.org/registry/-/registry-1.2.3.tgz')
+    t.strictSame(data.dependencies.registry.resolved,
+      'https://registry.npmjs.org/registry/-/registry-1.2.3.tgz')
+
+    // scoped packages that resolve to their configured registry should be
+    // record the default registry
+    t.strictSame(data.packages['node_modules/@scope/some-package'].resolved,
+      'https://registry.npmjs.org/registry/-/registry-1.2.3.tgz')
+    t.strictSame(data.dependencies['@scope/some-package'].resolved,
+      'https://registry.npmjs.org/registry/-/registry-1.2.3.tgz')
+
+    // packages with resolved urls that don't match the configured registry
+    // should record undefined so npm resolves their url again.
+    t.strictSame(data.packages['node_modules/some-other-registry'].resolved, undefined)
+    t.strictSame(data.dependencies['some-other-registry'].resolved, undefined)
+  })
+
   t.test('metaFromNode default', async t => {
     // test to cover options default.
     const { registry } = await getData(undefined)