Add functionality to create relative links

This commit adds an option to the extended configuration syntax for
linking files and directories. Enabling the relative option makes it so
that symbolic links are created with relative paths instead of absolute
paths.

README.md

@@ -83,7 +83,7 @@ The conventional name for the configuration file is `install.conf.yaml`.
 - link:
     ~/.dotfiles: ''
     ~/.tmux.conf: tmux.conf
-    ~/.vim: vim/
+    ~/.vim: vim
     ~/.vimrc: vimrc
 
 - shell:
@@ -104,7 +104,7 @@ The conventional name for this file is `install.conf.json`.
         "link": {
             "~/.dotfiles": "",
             "~/.tmux.conf": "tmux.conf",
-            "~/.vim": "vim/",
+            "~/.vim": "vim",
             "~/.vimrc": "vimrc"
         }
     },
@@ -147,7 +147,7 @@ files if necessary. Environment variables in paths are automatically expanded.
 
 Link commands are specified as a dictionary mapping targets to source
 locations. Source locations are specified relative to the base directory (that
-is specified when running the installer). Source directory names should contain
+is specified when running the installer). Directory names should *not* contain
 a trailing "/" character.
 
 Link commands support an (optional) extended configuration. In this type of
@@ -155,8 +155,9 @@ configuration, instead of specifying source locations directly, targets are
 mapped to extended configuration dictionaries. These dictionaries map `path` to
 the source path, specify `create` as `true` if the parent directory should be
 created if necessary, specify `relink` as `true` if incorrect symbolic links
-should be automatically overwritten, and specify `force` as `true` if the file
-or directory should be forcibly linked.
+should be automatically overwritten, specify `force` as `true` if the file or
+directory should be forcibly linked, and specify `relative` as `true` if the
+symbolic link should have a relative path.
 
 #### Example
 
@@ -164,8 +165,8 @@ or directory should be forcibly linked.
 - link:
     ~/.config/terminator:
       create: true
-      path: config/terminator/
-    ~/.vim: vim/
+      path: config/terminator
+    ~/.vim: vim
     ~/.vimrc:
       relink: true
       path: vimrc

plugins/link.py

@@ -23,6 +23,7 @@ class Link(dotbot.Plugin):
             if isinstance(source, dict):
                 # extended config
                 path = source['path']
+                relative = source.get('relative', False)
                 force = source.get('force', False)
                 relink = source.get('relink', False)
                 create = source.get('create', False)
@@ -33,8 +34,9 @@ class Link(dotbot.Plugin):
                 elif relink:
                     success &= self._delete(path, destination, force=False)
             else:
+                relative = False
                 path = source
-            success &= self._link(path, destination)
+            success &= self._link(path, destination, relative)
         if success:
             self._log.info('All links have been set up')
         else:
@@ -101,7 +103,7 @@ class Link(dotbot.Plugin):
                     self._log.lowinfo('Removing %s' % path)
         return success
 
-    def _link(self, source, link_name):
+    def _link(self, source, link_name, relative):
         '''
         Links link_name to source.
 
@@ -115,7 +117,11 @@ class Link(dotbot.Plugin):
                 (link_name, self._link_destination(link_name)))
         elif not self._exists(link_name) and self._exists(source):
             try:
-                os.symlink(source, os.path.expanduser(link_name))
+                destination = os.path.expanduser(link_name)
+                if relative:
+                    destination_dir = os.path.dirname(destination)
+                    source = os.path.relpath(source, destination_dir)
+                os.symlink(source, destination)
             except OSError:
                 self._log.warning('Linking failed %s -> %s' % (link_name, source))
             else:

test/tests/link-relative.bash

@@ -0,0 +1,36 @@
+test_description='relative linking works'
+. '../test-lib.bash'
+
+test_expect_success 'setup' '
+echo "apple" > ${DOTFILES}/f &&
+mkdir ${DOTFILES}/d &&
+echo "grape" > ${DOTFILES}/d/e
+'
+
+test_expect_success 'run' '
+run_dotbot <<EOF
+- link:
+    ~/.f:
+      path: f
+    ~/.frel:
+      path: f
+      relative: true
+    ~/nested/.frel:
+      path: f
+      create: true
+      relative: true
+    ~/.d:
+      path: d
+      relative: true
+EOF
+'
+
+test_expect_success 'test' '
+grep "apple" ~/.f &&
+grep "apple" ~/.frel &&
+[[ "$(readlink ~/.f)" == "$(readlink -f dotfiles/f)" ]] &&
+[[ "$(readlink ~/.frel)" == "dotfiles/f" ]] &&
+[[ "$(readlink ~/nested/.frel)" == "../dotfiles/f" ]] &&
+grep "grape" ~/.d/e &&
+[[ "$(readlink ~/.d)" == "dotfiles/d" ]]
+'