feat: automatically add linked files to gitignore

closes: #27

lib/hooks/link.nix

@@ -1,6 +1,8 @@
 { configFile, hookConfig }:
 let
   inherit (hookConfig) output extra;
+
+  gitignore-sentinel = "ignore-linked-files";
 in
 ''
   # Check if the link is pointing to the existing derivation result
@@ -25,4 +27,20 @@ in
     # this was an existing file
     error "refusing to overwrite ${output}"
   fi
+  # Add this output to gitignore if not already
+  if ! test -f .gitignore
+  then
+    touch .gitignore
+  fi
+  if ! grep -qF "${output}" .gitignore
+  then
+    if ! grep -qF "${gitignore-sentinel}" .gitignore
+    then
+      echo -e "\n# nixago: ${gitignore-sentinel}" >> .gitignore
+    fi
+    newgitignore="$(awk '1;/${gitignore-sentinel}/{ print "${output}"; }' .gitignore)"
+    echo -e -n "$newgitignore" > .gitignore
+    git add .gitignore
+    log "${output} added to .gitignore"
+  fi
 ''

tests/hook/default.nix

@@ -18,8 +18,10 @@ let
   linkHook = pkgs.writeShellScript "link" (lib.make linkRequest).shellHook;
   copyHook = pkgs.writeShellScript "copy" (lib.make copyRequest).shellHook;
 in
-pkgs.runCommand "test.hook" { }
+pkgs.runCommand "test.hook" { buildInputs = [ pkgs.gitMinimal ]; }
   ''
+    git init
+
     echo "Testing link hook"
     source ${linkHook}
     stat test.json
@@ -30,5 +32,7 @@ pkgs.runCommand "test.hook" { }
     stat test.json
     stat test.txt
 
+    rm -rf .git
+
     touch $out
   ''