Fix requirement which override

- preserve `Requirement#which` defaulting to `ORIGINAL_PATHS`
- match `Kernel#which` arity and visibility for Sorbet
- cover `which` inside `satisfy(build_env: false)` regression

Author: MikeMcQuaid

Library/Homebrew/requirement.rb

@@ -200,10 +200,11 @@ def infer_name
     ""
   end
 
-  sig { params(cmd: String).returns(T.nilable(Pathname)) }
-  def which(cmd)
-    super(cmd, PATH.new(ORIGINAL_PATHS))
+  sig { override.params(cmd: String, path: PATH::Elements).returns(T.nilable(Pathname)) }
+  def which(cmd, path = PATH.new(ORIGINAL_PATHS))
+    super
   end
+  public :which
 
   class << self
     include BuildEnvironment::DSL

Library/Homebrew/test/requirement_spec.rb

@@ -154,6 +154,20 @@
         requirement.modify_build_environment
       end
     end
+
+    describe "#satisfy with block calling #which and :build_env set to false" do
+      let(:klass) do
+        Class.new(described_class) do
+          satisfy(build_env: false) do
+            which("sh")
+          end
+        end
+      end
+
+      it "does not raise an error" do
+        expect { requirement.satisfied? }.not_to raise_error
+      end
+    end
   end
 
   describe "#build?" do