Fix bug when linking files that contain printf conversion specifications

The fix leads to a more robust way to loop through repository files
by using the -z flag of ls-files. It has been available
since git 1.5.0, so no dep requirement changes are necessary.
(See https://github.com/git/git/blob/v1.5.0/builtin-ls-files.c#L341-L344)

Reported in #223 by @ncallister. Thank you Nathan :-)

lib/commands/link.sh

@@ -94,7 +94,7 @@ get_repo_files() {
   root=$(cd "$1" && pwd -P)
   (
     local path
-    while IFS= read -d $'\n' -r path; do
+    while IFS= read -d $'\0' -r path; do
       # Remove quotes from ls-files
       # (used when there are newlines in the path)
       path=${path/#\"/}
@@ -104,23 +104,20 @@ get_repo_files() {
       # Remove the home/ part
       path=${path/#home\//}
       # Print the file path (NUL separated because \n can be used in filenames)
-      # Disable SC2059, using %s messes with the filename
-      # shellcheck disable=SC2059
-      printf "$path\0"
+      printf "%s\0" "$path"
       # Get the path of all the parent directories
       # up to the repo root.
       while true; do
         path=$(dirname "$path")
         # If path is '.' we're done
         [[ $path == '.' ]] && break
         # Print the path
-        # shellcheck disable=SC2059
-        printf "$path\0"
+        printf "%s\0" "$path"
       done
     # Enter the repo, list the repo root files in home
     # and do the same for any submodules
     done < <(cd "$root" &&
-             git ls-files 'home/' &&
+             git ls-files -z 'home/' &&
              git submodule --quiet foreach --recursive \
              "$homeshick/lib/submodule_files.sh \"$root\" \"\$toplevel\" \"\$path\"")
     # Unfortunately we have to use an external script for `git submodule foreach'

lib/submodule_files.sh

@@ -17,5 +17,5 @@ if [[ $repo =~ ^home ]]; then
   cd "$toplevel/$path"
   # List the files and prefix every line
   # with the relative repo path
-  git ls-files | sed "s#^#${repo//#/\\#}/#"
+  git ls-files -z | sed -z "s#^#${repo//#/\\#}/#"
 fi

test/fixtures/repo with spaces in name.sh

@@ -28,6 +28,8 @@ fixture_repo_with_spaces_in_name() {
 file␇☺"
   git add ".crazy
 file␇☺"
+  touch "%printf conver%sionchar%s %%"
+  git add "%printf conver%sionchar%s %%"
 
   git commit -m 'Add file with newline and all kinds of crazy characters in the name'
 }

test/suites/link.bats

@@ -21,6 +21,13 @@ file␇☺"
 file␇☺"
 }
 
+@test 'link file with printf conversion chars' {
+  castle 'repo with spaces in name'
+  homeshick --batch link 'repo with spaces in name'
+  stat "$HOME/%printf conver%sionchar%s %%"
+  test -f "$HOME/%printf conver%sionchar%s %%"
+}
+
 @test 'do not fail when linking file with newline' {
  castle 'rc-files'
  test_filename="filename