Make force only delete files when target exists

plugins/link.py

@@ -37,7 +37,8 @@ class Link(dotbot.Plugin):
             if create:
                 success &= self._create(destination)
             if force or relink:
-                success &= self._delete(path, destination, relative, force)
+                if self._exists(path):
+                    success &= self._delete(path, destination, relative, force)
             success &= self._link(path, destination, relative)
         if success:
             self._log.info('All links have been set up')

test/tests/link-force-leaves-when-nonexistent.bash

@@ -0,0 +1,24 @@
+test_description='force leaves file when target nonexistent'
+. '../test-lib.bash'
+
+test_expect_success 'setup' '
+mkdir ~/dir &&
+touch ~/file
+'
+
+test_expect_failure 'run' '
+run_dotbot <<EOF
+- link:
+    ~/dir:
+      path: dir
+      force: true
+    ~/file:
+      path: file
+      force: true
+EOF
+'
+
+test_expect_success 'test' '
+test -d ~/dir &&
+test -f ~/file
+'