From 7be6b8e6d1172b0a5a65944254c2ef4f73342ad4 Mon Sep 17 00:00:00 2001
From: Carlo Cabrera <30379873+carlocab@users.noreply.github.com>
Date: Tue, 2 Aug 2022 23:49:05 +0800
Subject: [PATCH] update-report: migrate GCC recursive dependents

When GCC 12 ships (Homebrew/homebrew-core#106755) ships, most (all?)
Linux bottles that depend on GCC will break.

Let's fix that by using the same trick for handling divergent formula
revisions when migrating formulae from linuxbrew-core (#11982). We set
the recorded `version_scheme` to -1, which spoofs the formula being
outdated. When `brew upgrade` installs GCC 12, the broken formulae will
have their bottles reinstalled too.

This works because the reinstallation will also rewrite the existing
RPATHs to point to the new version of GCC instead (#13631). This should
handle most of the breakage.
---
 Library/Homebrew/cmd/update-report.rb | 30 +++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

diff --git a/Library/Homebrew/cmd/update-report.rb b/Library/Homebrew/cmd/update-report.rb
index 89b8f50fca..b8aa5169f2 100644
--- a/Library/Homebrew/cmd/update-report.rb
+++ b/Library/Homebrew/cmd/update-report.rb
@@ -148,6 +148,8 @@ module Homebrew
     Homebrew.failed = true if ENV["HOMEBREW_UPDATE_FAILED"]
     return if Homebrew::EnvConfig.disable_load_formula?
 
+    migrate_gcc_dependents_if_needed
+
     hub = ReporterHub.new
 
     updated_taps = []
@@ -289,6 +291,34 @@ module Homebrew
         #{e}
     EOS
   end
+
+  def migrate_gcc_dependents_if_needed
+    return if OS.mac?
+
+    # TODO: Remove this block when GCC 12 ships.
+    begin
+      return if Formula["gcc"].version < 12
+    rescue FormulaUnavailableError
+      return if Homebrew::EnvConfig.install_from_api?
+    end
+
+    return if Settings.read("gcc.dependents.migrated") == "true"
+
+    Formula.installed.each do |formula|
+      next unless formula.tap.core_tap?
+      next unless formula.recursive_dependencies.map(&:name).include? "gcc"
+
+      keg = formula.installed_kegs.last
+      tab = Tab.for_keg(keg)
+      # Force reinstallation upon `brew upgrade` to fix the bottle RPATH.
+      tab.source["versions"]["version_scheme"] = -1
+      tab.write
+    rescue TapFormulaUnavailableError
+      nil
+    end
+
+    Settings.write "gcc.dependents.migrated", true
+  end
 end
 
 class Reporter