mkSymlinkActivationScript: add overall check for existence of source

flake.nix

@@ -12,10 +12,12 @@
     ];
 
     mkSymlinkActivationScript = {target, source}: ''
-      if [ -e ${target} ]; then
-        rm -rf ${target}
+      if [ -e ${source} ]; then
+        if [ -e ${target} ]; then
+          rm -rf ${target}
+        fi
+        ln -s ${source} ${target}
       fi
-      ln -s ${source} ${target}
     '';
 
     attrByStrPath = strPath: set: nixpkgs.lib.attrByPath (nixpkgs.lib.strings.splitString "." strPath) null set;