shrinkwrap: Stop churning ranges back to versions in requires

Credit: @iarna

lib/install/get-requested.js

@@ -2,9 +2,9 @@
 const npa = require('npm-package-arg')
 const moduleName = require('../utils/module-name.js')
 
-module.exports = function (child) {
+module.exports = function (child, reqBy) {
   if (!child.requiredBy.length) return
-  const reqBy = child.requiredBy[0]
+  if (!reqBy) reqBy = child.requiredBy[0]
   const deps = reqBy.package.dependencies || {}
   const devDeps = reqBy.package.devDependencies || {}
   const name = moduleName(child)

lib/shrinkwrap.js

@@ -134,8 +134,8 @@ function shrinkwrapDeps (deps, top, tree, seen) {
     if (child.requires.length) {
       pkginfo.requires = {}
       sortModules(child.requires).forEach((required) => {
-        var requested = required.package._requested || getRequested(required) || {}
-        pkginfo.requires[moduleName(required)] = childRequested(top, required, requested)
+        var requested = getRequested(required, child) || required.package._requested || {}
+        pkginfo.requires[moduleName(required)] = childRequested(top, child, required, requested)
       })
     }
     if (child.children.length) {
@@ -163,13 +163,15 @@ function childVersion (top, child, req) {
   }
 }
 
-function childRequested (top, child, req) {
-  if (req.type === 'directory' || req.type === 'file') {
-    return 'file:' + unixFormatPath(path.relative(top.path, child.package._resolved || req.fetchSpec))
-  } else if (!isRegistry(req) && !child.fromBundle) {
-    return child.package._resolved || req.saveSpec || req.rawSpec
-  } else if (req.saveSpec || req.rawSpec) {
-    return req.saveSpec || req.rawSpec
+function childRequested (top, parent, child, requested) {
+  if (parent.swRequires && parent.swRequires[moduleName(child)] === child.package.version) {
+    return child.package.version
+  } else if (requested.type === 'directory' || requested.type === 'file') {
+    return 'file:' + unixFormatPath(path.relative(top.path, child.package._resolved || requested.fetchSpec))
+  } else if (!isRegistry(requested) && !child.fromBundle) {
+    return child.package._resolved || requested.saveSpec || requested.rawSpec
+  } else if (requested.saveSpec || requested.rawSpec) {
+    return requested.saveSpec || requested.rawSpec
   } else if (child.package._from || (child.package._requested && child.package._requested.rawSpec)) {
     return child.package._from.replace(/^@?[^@]+@/, '') || child.package._requested.rawSpec
   } else {