Fix usage of numeric.

Author: ioquatix

lib/memory/usage.rb

@@ -61,7 +61,9 @@ def self.of(root)
 				size += ObjectSpace.memsize_of(object)
 
 				# Add the object's reachable objects to the queue:
-				queue.concat(ObjectSpace.reachable_objects_from(object))
+				if reachable_objects = ObjectSpace.reachable_objects_from(object)
+					queue.concat(reachable_objects)
+				end
 			end
 
 			return new(size, count)

releases.md

@@ -1,5 +1,9 @@
 # Releases
 
+## Unreleased
+
+  - Handle `Memory::Usage.of(number)` without error.
+
 ## v0.8.2
 
   - Fix several formatting issues.

test/memory/usage.rb

@@ -4,6 +4,7 @@
 # Copyright, 2022-2025, by Samuel Williams.
 
 require "memory/usage"
+require "json"
 
 describe Memory::Usage do
 	let(:usage) {subject.new}
@@ -139,6 +140,22 @@
 				size: be > 0
 			)
 		end
+		
+		it "can compute usage of nil" do
+			usage = subject.of(nil)
+			expect(usage).to have_attributes(
+				count: be == 0,
+				size: be == 0
+			)
+		end
+		
+		it "can compute usage of numbers" do
+			usage = subject.of(42)
+			expect(usage).to have_attributes(
+				count: be == 1,
+				size: be == 0
+			)
+		end
 	end
 
 	with "#to_s" do