Running nixpkgs-update (https://nix-community.org/update-bot/) with UPDATE_INFO: completely 0.7.1 -> 0.8.0 https://github.com/DannyBen/completely/releases
attrpath: completely
Checking auto update branch...
[version] 
[version] skipping because derivation has updateScript
[rustCrateVersion] 
[rustCrateVersion] No cargoHash found
[golangModuleVersion] 
[golangModuleVersion] Not a buildGoModule package with vendorHash
[npmDepsVersion] 
[npmDepsVersion] No npmDepsHash
[updateScript] 
[updateScript] Success
[updateScript] this derivation will be built:
  /nix/store/gmh68z1si4rzwnfb9rx4awdam7r4imwl-packages.json.drv
building '/nix/store/gmh68z1si4rzwnfb9rx4awdam7r4imwl-packages.json.drv'...

Going to be running update for following packages:
 - completely-0.7.1

Press Enter key to continue...
Running update for:
Enqueuing group of 1 packages
 - completely-0.7.1: UPDATING ...
 - completely-0.7.1: DONE.

Packages updated!

Diff after rewrites:
diff --git a/pkgs/by-name/co/completely/Gemfile.lock b/pkgs/by-name/co/completely/Gemfile.lock
index 53b2f0a2d03f..df3f53b7b68b 100644
--- a/pkgs/by-name/co/completely/Gemfile.lock
+++ b/pkgs/by-name/co/completely/Gemfile.lock
@@ -1,14 +1,20 @@
 GEM
   remote: https://rubygems.org/
   specs:
-    colsole (1.0.0)
-    completely (0.7.1)
-      colsole (>= 0.8.1, < 2)
+    colsole (1.0.1)
+    completely (0.8.0)
+      colsole (~> 1.0.0)
+      erb
       mister_bin (~> 0.7)
     docopt_ng (0.7.1)
-    mister_bin (0.8.1)
-      colsole (>= 0.8.1, < 2)
-      docopt_ng (~> 0.7, >= 0.7.1)
+    erb (6.0.7)
+    io-console (0.9.2)
+    mister_bin (0.9.0)
+      colsole (~> 1.0.0)
+      docopt_ng (~> 0.7.1)
+      reline (~> 0.6)
+    reline (0.7.0)
+      io-console (~> 0.5)
 
 PLATFORMS
   ruby
@@ -17,4 +23,4 @@ DEPENDENCIES
   completely
 
 BUNDLED WITH
-   2.6.6
+   2.7.2
diff --git a/pkgs/by-name/co/completely/gemset.nix b/pkgs/by-name/co/completely/gemset.nix
index ec0d8c65df42..92247bbcac15 100644
--- a/pkgs/by-name/co/completely/gemset.nix
+++ b/pkgs/by-name/co/completely/gemset.nix
@@ -4,24 +4,25 @@
     platforms = [ ];
     source = {
       remotes = [ "https://rubygems.org" ];
-      sha256 = "1fvf6dz2wsvjk7q24z0dm8lajq3p2l6i5ywf3mxj683rmhwq49bg";
+      sha256 = "00kvcnfnqiczrrdbfr0jwhvwym29d0y43zjg09y8gnz2mh0a6ckn";
       type = "gem";
     };
-    version = "1.0.0";
+    version = "1.0.1";
   };
   completely = {
     dependencies = [
       "colsole"
+      "erb"
       "mister_bin"
     ];
     groups = [ "default" ];
     platforms = [ ];
     source = {
       remotes = [ "https://rubygems.org" ];
-      sha256 = "0129alz54h2vy7vd19i5664sasdbvrl4zgj70hl5j4rpvckr5lf8";
+      sha256 = "0pkciknwlfkxjmdbww6nprim7wz5pzn7gwj1ga8lfpw0hifwv4z4";
       type = "gem";
     };
-    version = "0.7.1";
+    version = "0.8.0";
   };
   docopt_ng = {
     groups = [ "default" ];
@@ -33,18 +34,50 @@
     };
     version = "0.7.1";
   };
+  erb = {
+    groups = [ "default" ];
+    platforms = [ ];
+    source = {
+      remotes = [ "https://rubygems.org" ];
+      sha256 = "14pfj6zn0p1hxj6s6s0r7d424wap8zl9zxf89nj79y8fbg16vjn5";
+      type = "gem";
+    };
+    version = "6.0.7";
+  };
+  io-console = {
+    groups = [ "default" ];
+    platforms = [ ];
+    source = {
+      remotes = [ "https://rubygems.org" ];
+      sha256 = "026v93kja19bfslnwi9xfq2dj4r89kkwdprim4whjg6h3n4lz9zg";
+      type = "gem";
+    };
+    version = "0.9.2";
+  };
   mister_bin = {
     dependencies = [
       "colsole"
       "docopt_ng"
+      "reline"
     ];
     groups = [ "default" ];
     platforms = [ ];
     source = {
       remotes = [ "https://rubygems.org" ];
-      sha256 = "1zz3vpy6xrgzln2dpxgcnrq1bpzz0syl60whqc9zf8j29mayw1fy";
+      sha256 = "1lz7kc3nj4h0avk4zfkc7ahrfxl242ry05scx1w1kbsgvc0y8kv2";
+      type = "gem";
+    };
+    version = "0.9.0";
+  };
+  reline = {
+    dependencies = [ "io-console" ];
+    groups = [ "default" ];
+    platforms = [ ];
+    source = {
+      remotes = [ "https://rubygems.org" ];
+      sha256 = "0gaq2lc463ap1srz7y5kh2p4dxazs7vjrpiby58d9yfvan72s0av";
       type = "gem";
     };
-    version = "0.8.1";
+    version = "0.7.0";
   };
 }

No auto update branch exists
Old version 0.7.1" not present in master derivation file with contents: {
  lib,
  bundlerApp,
  bundlerUpdateScript,
}:

bundlerApp {
  pname = "completely";

  gemdir = ./.;
  exes = [ "completely" ];

  passthru.updateScript = bundlerUpdateScript "completely";

  meta = {
    description = "Generate bash completion scripts using a simple configuration file";
    homepage = "https://github.com/DannyBen/completely";
    license = lib.licenses.mit;
    platforms = lib.platforms.unix;
    maintainers = with lib.maintainers; [ zendo ];
    mainProgram = "completely";
  };
}