Use silly-high version number for linked packages.

doc/link.md

@@ -11,3 +11,15 @@ This will link a source folder into npm's registry using a symlink, and then
 build it according to the package.json file in that folder's root. This is
 handy for installing your own stuff, so that you can work on it and test it
 iteratively without having to continually rebuild.
+
+## Linked Package Version
+
+When linking a package folder, npm doesn't use the version in the
+package.json file.  Instead, it creates a "fake" version number of:
+
+    "9999.0.0-LINK-" + hash(folder)
+
+This way, linking the same folder will always result in the same version
+number, even if you bump the version in the package.json file.  The
+extremely high major version ensures that it will always be considered
+the "highest" version, since it is a development bleeding-edge thing.

lib/link.js

@@ -45,7 +45,7 @@ function link (args, cb) {
 function readAndLink (jsonFile, folder, cb) {
   readJson
     ( jsonFile
-    , { "tag" : "-1-LINK-"+(
+    , { "tag" : "9999.0.0-LINK-"+(
         crypto.createHash("sha1").update(folder).digest("hex").substr(0,8)
       )}
     , doLink(folder, cb)

lib/utils/read-json.js

@@ -85,15 +85,7 @@ function processObject (opts, cb) { return function (er, json) {
     throw e
   }
   var tag = opts.tag
-  if (tag && tag.indexOf(json.version) === 0) {
-    tag = tag.substr(json.version.length)
-  }
-  if (tag && tag.indexOf("-1-LINK") !== -1) {
-    tag = tag.substr(tag.indexOf("-1-LINK"))
-  }
-  if (tag && semver.valid(json.version + tag)) {
-    json.version += tag
-  }
+  if (tag) json.version = tag//+"-"+json.version
 
   // FIXME: uncomment in 0.3.0, once it's not likely that people will
   // have a bunch of main.js files kicking around any more, and remove