Document parsePackedRefs

Author: tmcw

lib/git/url_prefix.js

@@ -3,6 +3,17 @@ var path = require('path');
 var gitUrlParse = require('git-url-parse');
 var getRemoteOrigin = require('remote-origin-url');
 
+/**
+ * Sometimes git will [pack refs](https://git-scm.com/docs/git-pack-refs)
+ * in order to save space on disk and
+ * duck under limits of numbers of files in folders. CircleCI in particular
+ * does this by default. This method parses that `packed-refs` file
+ *
+ * @private
+ * @param {string} packedRefs string contents of the packed refs file
+ * @param {string} branchName the branch name to resolve to
+ * @returns {string} sha hash referring to current tree
+ */
 function parsePackedRefs(packedRefs, branchName) {
   return packedRefs.split(/\n/)
     .filter(function (line) {