From 718cf8b0df5666001dce4fa73a88c70218b98252 Mon Sep 17 00:00:00 2001
From: Carlo Cabrera <30379873+carlocab@users.noreply.github.com>
Date: Mon, 22 Aug 2022 14:54:52 +0800
Subject: [PATCH] Fix Linux-only GCC dependency check.

This is based on feedback from code review.
---
 Library/Homebrew/formula_auditor.rb | 31 +++++++++++++++--------------
 1 file changed, 16 insertions(+), 15 deletions(-)

diff --git a/Library/Homebrew/formula_auditor.rb b/Library/Homebrew/formula_auditor.rb
index 9d51183606..3ecabea98f 100644
--- a/Library/Homebrew/formula_auditor.rb
+++ b/Library/Homebrew/formula_auditor.rb
@@ -333,21 +333,11 @@ module Homebrew
 
       return unless @core_tap
 
-      # Prevent formulae from declaring Linux-only dependencies on GCC,
-      # or else its dependency tree grows out of control.
-      on_linux_deps = formula.to_hash_with_variations.dig("variations", :x86_64_linux, "dependencies")
-      if on_linux_deps&.include? "gcc"
-        bad_gcc_dep = @strict || begin
-          fv = FormulaVersions.new(formula)
-          prev_on_linux_deps = fv.formula_at_revision("origin/HEAD") do |prev_f|
-            prev_f.to_hash_with_variations.dig("variations", :x86_64_linux, "dependencies")
-          end
-
-          prev_on_linux_deps&.exclude? "gcc"
-        end
-
-        problem "Formulae in homebrew/core should not have a Linux-only dependency on GCC." if bad_gcc_dep
-      end
+      bad_gcc_dep = linux_only_gcc_dep?(formula) && (@strict || begin
+        fv = FormulaVersions.new(formula)
+        fv.formula_at_revision("origin/HEAD") { |prev_f| !linux_only_gcc_dep?(prev_f) }
+      end)
+      problem "Formulae in homebrew/core should not have a Linux-only dependency on GCC." if bad_gcc_dep
 
       return if formula.tap&.audit_exception :versioned_dependencies_conflicts_allowlist, formula.name
 
@@ -865,5 +855,16 @@ module Homebrew
     def head_only?(formula)
       formula.head && formula.stable.nil?
     end
+
+    def linux_only_gcc_dep?(formula)
+      # TODO: Make this check work when running on Linux and not simulating macOS too.
+      return false unless Homebrew::SimulateSystem.simulating_or_running_on_macos?
+
+      formula_hash = formula.to_hash_with_variations
+      deps = formula_hash["dependencies"]
+      linux_deps = formula_hash.dig("variations", :x86_64_linux, "dependencies")
+
+      deps.exclude?("gcc") && linux_deps&.include?("gcc")
+    end
   end
 end