Empty final lines in DESCRIPTION

for GitHub packages confuse packrat, e.g.:

https://github.com/duncantl/CodeDepends/blob/5993c81057f2f41e215e1590e948afa8a5708ce9/DESCRIPTION#L25

Which part of the code concatenates the package's DESCRIPTION with packrat's special fields? I'm seeing the following temporary DESCRIPTION that eventually leads to an error:

Package: CodeDepends
Version: 0.5-5.6
Title: Analysis of R Code for Reproducible Research and Code Comprehension
Description: Tools for analyzing R expressions
  or blocks of code and determining the dependencies between them.
  It focuses on R scripts, but can be used on the bodies of functions.
  There are many facilities including the ability to summarize  or get a high-level
  view of code, determining dependencies between variables,  code improvement
  suggestions.
Author: Duncan Temple Lang, Roger Peng, Deborah Nolan, Gabriel Becker
Maintainer:  Gabriel Becker <becker.gabriel@gene.com> 
License: GPL
URL: https://github.com/duncantl/CodeDepends
BugReports: https://github.com/duncantl/CodeDepends/issues
Depends: methods
Imports: codetools, graph, XML, utils
Suggests: Rgraphviz, RUnit, knitr,  highlight, RJSONIO, RCurl, Rcpp
VignetteBuilder: knitr
Collate: classes.R librarySymbols.R functionHandlers.R codeDepends.R sectionDepends.R sweave.R xml.R 
         jss.R frags.R codeTypes.R gc.R graph.R parallel.R 
         deps.R separateBlocks.R callGraph.R isPlot.R isOutput.R 
         refScript.R sideEffects.R 
         highlightCode.R freeVariables.R
         convenienceFuns.R

GithubRepo: CodeDepends
GithubUsername: duncantl
GithubRef: master
GithubSHA1: 5993c81057f2f41e215e1590e948afa8a5708ce9

(Sorry, no reprex.)

The issue names no files or tests; begin by locating the code that creates the temporary DESCRIPTION and appends Packrat fields, then reproduce the problem with the linked CodeDepends DESCRIPTION. Done means the generated metadata no longer contains problematic empty final lines and the reported error is resolved.