Merge pull request #15778 from Bo98/dep-source-fix

formula_installer: use cached fetched formula instance when available

Library/Homebrew/formula_installer.rb

@@ -96,6 +96,9 @@ def initialize(
     @requirement_messages = []
     @poured_bottle = false
     @start_time = nil
+
+    # Take the original formula instance, which might have been swapped from an API instance to a source instance
+    @formula = previously_fetched_formula if previously_fetched_formula
   end
 
   def self.attempted
@@ -1182,9 +1185,17 @@ def fetch_dependencies
     deps.each { |dep, _options| fetch_dependency(dep) }
   end
 
+  sig { returns(T.nilable(Formula)) }
+  def previously_fetched_formula
+    # We intentionally don't compare classes here.
+    self.class.fetched.find do |fetched_formula|
+      fetched_formula.full_name == formula.full_name && fetched_formula.active_spec_sym == formula.active_spec_sym
+    end
+  end
+
   sig { void }
   def fetch
-    return if self.class.fetched.include?(formula)
+    return if previously_fetched_formula
 
     fetch_dependencies