diff --git a/Library/Homebrew/unpack_strategy.rb b/Library/Homebrew/unpack_strategy.rb
index b3581c8ad7..382e82533d 100644
--- a/Library/Homebrew/unpack_strategy.rb
+++ b/Library/Homebrew/unpack_strategy.rb
@@ -187,7 +187,7 @@ module UnpackStrategy
     end
   end
 
-  sig { returns(T::Array[String]) }
+  sig { returns(T.any(T::Array[Cask::Cask], T::Array[Formula])) }
   def dependencies
     []
   end
diff --git a/Library/Homebrew/unpack_strategy/air.rb b/Library/Homebrew/unpack_strategy/air.rb
index 6415995419..371fc29ae8 100644
--- a/Library/Homebrew/unpack_strategy/air.rb
+++ b/Library/Homebrew/unpack_strategy/air.rb
@@ -17,7 +17,7 @@ module UnpackStrategy
       path.magic_number.match?(/.{59}#{Regexp.escape(mime_type)}/)
     end
 
-    sig { returns(T.nilable(T::Array[Cask::Cask])) }
+    sig { returns(T::Array[Cask::Cask]) }
     def dependencies
       @dependencies ||= T.let([Cask::CaskLoader.load("adobe-air")], T.nilable(T::Array[Cask::Cask]))
     end
diff --git a/Library/Homebrew/unpack_strategy/cab.rb b/Library/Homebrew/unpack_strategy/cab.rb
index a4cc7993a6..cb3aa57ee9 100644
--- a/Library/Homebrew/unpack_strategy/cab.rb
+++ b/Library/Homebrew/unpack_strategy/cab.rb
@@ -16,6 +16,11 @@ module UnpackStrategy
       path.magic_number.match?(/\AMSCF/n)
     end
 
+    sig { returns(T::Array[Formula]) }
+    def dependencies
+      @dependencies ||= T.let([Formula["cabextract"]], T.nilable(T::Array[Formula]))
+    end
+
     sig { override.params(unpack_dir: Pathname, basename: Pathname, verbose: T::Boolean).void }
     def extract_to_dir(unpack_dir, basename:, verbose:)
       system_command! "cabextract",
@@ -23,10 +28,5 @@ module UnpackStrategy
                       env:     { "PATH" => PATH.new(Formula["cabextract"].opt_bin, ENV.fetch("PATH")) },
                       verbose:
     end
-
-    sig { returns(T.nilable(T::Array[Formula])) }
-    def dependencies
-      @dependencies ||= T.let([Formula["cabextract"]], T.nilable(T::Array[Formula]))
-    end
   end
 end
diff --git a/Library/Homebrew/unpack_strategy/generic_unar.rb b/Library/Homebrew/unpack_strategy/generic_unar.rb
index ecc6e2c256..d5ef55bf61 100644
--- a/Library/Homebrew/unpack_strategy/generic_unar.rb
+++ b/Library/Homebrew/unpack_strategy/generic_unar.rb
@@ -16,7 +16,7 @@ module UnpackStrategy
       false
     end
 
-    sig { returns(T.nilable(T::Array[Formula])) }
+    sig { returns(T::Array[Formula]) }
     def dependencies
       @dependencies ||= T.let([Formula["unar"]], T.nilable(T::Array[Formula]))
     end
diff --git a/Library/Homebrew/unpack_strategy/lha.rb b/Library/Homebrew/unpack_strategy/lha.rb
index 0fdb49ed55..c20f7e6521 100644
--- a/Library/Homebrew/unpack_strategy/lha.rb
+++ b/Library/Homebrew/unpack_strategy/lha.rb
@@ -16,7 +16,7 @@ module UnpackStrategy
       path.magic_number.match?(/\A..-(lh0|lh1|lz4|lz5|lzs|lh\\40|lhd|lh2|lh3|lh4|lh5)-/n)
     end
 
-    sig { returns(T.nilable(T::Array[Formula])) }
+    sig { returns(T::Array[Formula]) }
     def dependencies
       @dependencies ||= T.let([Formula["lha"]], T.nilable(T::Array[Formula]))
     end
diff --git a/Library/Homebrew/unpack_strategy/lzip.rb b/Library/Homebrew/unpack_strategy/lzip.rb
index 710f3684db..732897a922 100644
--- a/Library/Homebrew/unpack_strategy/lzip.rb
+++ b/Library/Homebrew/unpack_strategy/lzip.rb
@@ -16,7 +16,7 @@ module UnpackStrategy
       path.magic_number.match?(/\ALZIP/n)
     end
 
-    sig { returns(T.nilable(T::Array[Formula])) }
+    sig { returns(T::Array[Formula]) }
     def dependencies
       @dependencies ||= T.let([Formula["lzip"]], T.nilable(T::Array[Formula]))
     end
diff --git a/Library/Homebrew/unpack_strategy/lzma.rb b/Library/Homebrew/unpack_strategy/lzma.rb
index d1b6710c42..a4ff75ac0b 100644
--- a/Library/Homebrew/unpack_strategy/lzma.rb
+++ b/Library/Homebrew/unpack_strategy/lzma.rb
@@ -16,7 +16,7 @@ module UnpackStrategy
       path.magic_number.match?(/\A\]\000\000\200\000/n)
     end
 
-    sig { returns(T.nilable(T::Array[Formula])) }
+    sig { returns(T::Array[Formula]) }
     def dependencies
       @dependencies ||= T.let([Formula["xz"]], T.nilable(T::Array[Formula]))
     end
diff --git a/Library/Homebrew/unpack_strategy/p7zip.rb b/Library/Homebrew/unpack_strategy/p7zip.rb
index 44a8c4b986..c1e10cfb92 100644
--- a/Library/Homebrew/unpack_strategy/p7zip.rb
+++ b/Library/Homebrew/unpack_strategy/p7zip.rb
@@ -16,7 +16,7 @@ module UnpackStrategy
       path.magic_number.match?(/\A7z\xBC\xAF\x27\x1C/n)
     end
 
-    sig { returns(T.nilable(T::Array[Formula])) }
+    sig { returns(T::Array[Formula]) }
     def dependencies
       @dependencies ||= T.let([Formula["p7zip"]], T.nilable(T::Array[Formula]))
     end
diff --git a/Library/Homebrew/unpack_strategy/rar.rb b/Library/Homebrew/unpack_strategy/rar.rb
index 7d8109d654..8336d99b08 100644
--- a/Library/Homebrew/unpack_strategy/rar.rb
+++ b/Library/Homebrew/unpack_strategy/rar.rb
@@ -16,7 +16,7 @@ module UnpackStrategy
       path.magic_number.match?(/\ARar!/n)
     end
 
-    sig { returns(T.nilable(T::Array[Formula])) }
+    sig { returns(T::Array[Formula]) }
     def dependencies
       @dependencies ||= T.let([Formula["libarchive"]], T.nilable(T::Array[Formula]))
     end
diff --git a/Library/Homebrew/unpack_strategy/xz.rb b/Library/Homebrew/unpack_strategy/xz.rb
index 2e155c687b..55b6d289de 100644
--- a/Library/Homebrew/unpack_strategy/xz.rb
+++ b/Library/Homebrew/unpack_strategy/xz.rb
@@ -16,7 +16,7 @@ module UnpackStrategy
       path.magic_number.match?(/\A\xFD7zXZ\x00/n)
     end
 
-    sig { returns(T.nilable(T::Array[Formula])) }
+    sig { returns(T::Array[Formula]) }
     def dependencies
       @dependencies ||= T.let([Formula["xz"]], T.nilable(T::Array[Formula]))
     end
diff --git a/Library/Homebrew/unpack_strategy/zstd.rb b/Library/Homebrew/unpack_strategy/zstd.rb
index 475b0ca518..38a3328f32 100644
--- a/Library/Homebrew/unpack_strategy/zstd.rb
+++ b/Library/Homebrew/unpack_strategy/zstd.rb
@@ -16,7 +16,7 @@ module UnpackStrategy
       path.magic_number.match?(/\x28\xB5\x2F\xFD/n)
     end
 
-    sig { returns(T.nilable(T::Array[Formula])) }
+    sig { returns(T::Array[Formula]) }
     def dependencies
       @dependencies ||= T.let([Formula["zstd"]], T.nilable(T::Array[Formula]))
     end