From 5e0b786da21564011be7df165ce20a61d639de77 Mon Sep 17 00:00:00 2001
From: Carlo Cabrera <30379873+carlocab@users.noreply.github.com>
Date: Thu, 22 Jul 2021 00:43:46 +0800
Subject: [PATCH 1/6] formula: add `deuniversalize_machos` method

This method takes an optional array of `Pathnames`s or `Strings`s and
extracts the native slice from the specified universal binary. If no
parameter is supplied, this is done on all compatible universal binaries
in a formula's keg.

`deuniversalize_machos` is a no-op on Linux.

I still need to look into a) error handling, and b) whether using this
method requires codesigning on ARM.

I've also added signatures to the methods in `extend/os/linux/formula`.
---
 Library/Homebrew/extend/os/linux/formula.rb |  6 ++++++
 Library/Homebrew/formula.rb                 | 15 +++++++++++++++
 2 files changed, 21 insertions(+)

diff --git a/Library/Homebrew/extend/os/linux/formula.rb b/Library/Homebrew/extend/os/linux/formula.rb
index fde9216664..da2d162bdf 100644
--- a/Library/Homebrew/extend/os/linux/formula.rb
+++ b/Library/Homebrew/extend/os/linux/formula.rb
@@ -4,7 +4,9 @@
 class Formula
   undef shared_library
   undef rpath
+  undef deuniversalize_machos
 
+  sig { params(name: String, version: T.nilable(T.any(String, Integer))).returns(String) }
   def shared_library(name, version = nil)
     suffix = if version == "*" || (name == "*" && version.blank?)
       "{,.*}"
@@ -14,10 +16,14 @@ class Formula
     "#{name}.so#{suffix}"
   end
 
+  sig { returns(String) }
   def rpath
     "'$ORIGIN/../lib'"
   end
 
+  sig { params(targets: T.nilable(T.any(Pathname, String))).void }
+  def deuniversalize_machos(*targets); end
+
   class << self
     undef ignore_missing_libraries
 
diff --git a/Library/Homebrew/formula.rb b/Library/Homebrew/formula.rb
index a368b9a532..3ce605123b 100644
--- a/Library/Homebrew/formula.rb
+++ b/Library/Homebrew/formula.rb
@@ -1582,6 +1582,21 @@ class Formula
     end
   end
 
+  sig { params(targets: T.nilable(T.any(Pathname, String))).void }
+  def deuniversalize_machos(*targets)
+    if targets.blank?
+      targets = any_installed_keg.mach_o_files.select do |file|
+        file.arch == :universal && file.archs.include?(Hardware::CPU.arch)
+      end
+    end
+
+    targets.each do |t|
+      macho = MachO::FatFile.new(t)
+      native_slice = macho.extract(Hardware::CPU.arch)
+      native_slice.write t
+    end
+  end
+
   # an array of all core {Formula} names
   # @private
   def self.core_names

From a8527f4c16d7df419f6539fd583302635ec98a4a Mon Sep 17 00:00:00 2001
From: Carlo Cabrera <30379873+carlocab@users.noreply.github.com>
Date: Sat, 24 Jul 2021 19:39:47 +0800
Subject: [PATCH 2/6] Ensure writability, handle errors

---
 Library/Homebrew/formula.rb | 23 ++++++++++++++++++++---
 1 file changed, 20 insertions(+), 3 deletions(-)

diff --git a/Library/Homebrew/formula.rb b/Library/Homebrew/formula.rb
index 3ce605123b..5081cc20bb 100644
--- a/Library/Homebrew/formula.rb
+++ b/Library/Homebrew/formula.rb
@@ -1582,6 +1582,10 @@ class Formula
     end
   end
 
+  # Replaces a universal binary with its native slice.
+  #
+  # If called with no parameters, does this with all compatible
+  # universal binaries in a {Formula}'s {Keg}.
   sig { params(targets: T.nilable(T.any(Pathname, String))).void }
   def deuniversalize_machos(*targets)
     if targets.blank?
@@ -1590,10 +1594,23 @@ class Formula
       end
     end
 
-    targets.each do |t|
-      macho = MachO::FatFile.new(t)
+    targets.each { |t| extract_slice_from(Pathname.new(t), Hardware::CPU.arch) }
+  end
+
+  # @private
+  sig { params(file: Pathname, arch: T.nilable(Symbol)).void }
+  def extract_slice_from(file, arch = Hardware::CPU.arch)
+    odebug "Extracting #{arch} slice from #{file}"
+    file.ensure_writable do
+      macho = MachO::FatFile.new(file)
       native_slice = macho.extract(Hardware::CPU.arch)
-      native_slice.write t
+      native_slice.write file
+    rescue MachO::MachOBinaryError
+      onoe "#{file} is not a universal binary"
+      raise
+    rescue NoMethodError
+      onoe "#{file} does not contain an #{arch} slice"
+      raise
     end
   end
 

From 5128b92d3ef7616a35b7c3ad4f13ded0cfa5d683 Mon Sep 17 00:00:00 2001
From: Carlo Cabrera <30379873+carlocab@users.noreply.github.com>
Date: Sun, 25 Jul 2021 11:29:33 +0800
Subject: [PATCH 3/6] Use slightly more suggestive method name for extracting
 slices

`extract_slice_from` is still a little ambiguous, so let's try to give
it a more suggestive name.
---
 Library/Homebrew/formula.rb | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/Library/Homebrew/formula.rb b/Library/Homebrew/formula.rb
index 5081cc20bb..aa2533de0f 100644
--- a/Library/Homebrew/formula.rb
+++ b/Library/Homebrew/formula.rb
@@ -1594,12 +1594,12 @@ class Formula
       end
     end
 
-    targets.each { |t| extract_slice_from(Pathname.new(t), Hardware::CPU.arch) }
+    targets.each { |t| extract_macho_slice_from(Pathname.new(t), Hardware::CPU.arch) }
   end
 
   # @private
   sig { params(file: Pathname, arch: T.nilable(Symbol)).void }
-  def extract_slice_from(file, arch = Hardware::CPU.arch)
+  def extract_macho_slice_from(file, arch = Hardware::CPU.arch)
     odebug "Extracting #{arch} slice from #{file}"
     file.ensure_writable do
       macho = MachO::FatFile.new(file)

From 542694728ca63007430f0bfa369a941669c5351d Mon Sep 17 00:00:00 2001
From: Carlo Cabrera <30379873+carlocab@users.noreply.github.com>
Date: Sun, 25 Jul 2021 23:21:26 +0800
Subject: [PATCH 4/6] codesign binaries on ARM

---
 Library/Homebrew/formula.rb | 1 +
 1 file changed, 1 insertion(+)

diff --git a/Library/Homebrew/formula.rb b/Library/Homebrew/formula.rb
index aa2533de0f..d2f81510d4 100644
--- a/Library/Homebrew/formula.rb
+++ b/Library/Homebrew/formula.rb
@@ -1605,6 +1605,7 @@ class Formula
       macho = MachO::FatFile.new(file)
       native_slice = macho.extract(Hardware::CPU.arch)
       native_slice.write file
+      MachO.codesign! file if Hardware::CPU.arm?
     rescue MachO::MachOBinaryError
       onoe "#{file} is not a universal binary"
       raise

From fa635db8a1bd7494c355416421d52f87cdd0491c Mon Sep 17 00:00:00 2001
From: Carlo Cabrera <30379873+carlocab@users.noreply.github.com>
Date: Tue, 17 Aug 2021 22:32:52 +0800
Subject: [PATCH 5/6] Simplify re-definition of `targets`

---
 Library/Homebrew/formula.rb | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/Library/Homebrew/formula.rb b/Library/Homebrew/formula.rb
index d2f81510d4..3a0f29fc37 100644
--- a/Library/Homebrew/formula.rb
+++ b/Library/Homebrew/formula.rb
@@ -1588,10 +1588,8 @@ class Formula
   # universal binaries in a {Formula}'s {Keg}.
   sig { params(targets: T.nilable(T.any(Pathname, String))).void }
   def deuniversalize_machos(*targets)
-    if targets.blank?
-      targets = any_installed_keg.mach_o_files.select do |file|
-        file.arch == :universal && file.archs.include?(Hardware::CPU.arch)
-      end
+    targets ||= any_installed_keg.mach_o_files.select do |file|
+      file.arch == :universal && file.archs.include?(Hardware::CPU.arch)
     end
 
     targets.each { |t| extract_macho_slice_from(Pathname.new(t), Hardware::CPU.arch) }

From f20d61df9a61e9074b65f09839a2e6ba59187bd7 Mon Sep 17 00:00:00 2001
From: Carlo Cabrera <30379873+carlocab@users.noreply.github.com>
Date: Tue, 17 Aug 2021 22:47:08 +0800
Subject: [PATCH 6/6] Fix typecheck error

---
 Library/Homebrew/formula.rb | 1 +
 1 file changed, 1 insertion(+)

diff --git a/Library/Homebrew/formula.rb b/Library/Homebrew/formula.rb
index 3a0f29fc37..cc8601851f 100644
--- a/Library/Homebrew/formula.rb
+++ b/Library/Homebrew/formula.rb
@@ -1588,6 +1588,7 @@ class Formula
   # universal binaries in a {Formula}'s {Keg}.
   sig { params(targets: T.nilable(T.any(Pathname, String))).void }
   def deuniversalize_machos(*targets)
+    targets = nil if targets.blank?
     targets ||= any_installed_keg.mach_o_files.select do |file|
       file.arch == :universal && file.archs.include?(Hardware::CPU.arch)
     end