Merge pull request #13873 from Bo98/glibc-keg-only

Changes to allow keg-only glibc

Library/Homebrew/extend/os/linux/development_tools.rb

@@ -8,10 +8,15 @@ class DevelopmentTools
     sig { params(tool: String).returns(T.nilable(Pathname)) }
     def locate(tool)
       (@locate ||= {}).fetch(tool) do |key|
-        @locate[key] = if (path = HOMEBREW_PREFIX/"bin/#{tool}").executable?
+        @locate[key] = if build_system_too_old? &&
-          path
+                          (binutils_path = HOMEBREW_PREFIX/"opt/binutils/bin/#{tool}").executable?
-        elsif File.executable?(path = "/usr/bin/#{tool}")
+          binutils_path
-          Pathname.new path
+        elsif build_system_too_old? && (glibc_path = HOMEBREW_PREFIX/"opt/glibc/bin/#{tool}").executable?
+          glibc_path
+        elsif (homebrew_path = HOMEBREW_PREFIX/"bin/#{tool}").executable?
+          homebrew_path
+        elsif File.executable?(system_path = "/usr/bin/#{tool}")
+          Pathname.new system_path
         end
       end
     end
@@ -30,7 +35,7 @@ class DevelopmentTools
 
     sig { returns(T::Boolean) }
     def system_gcc_too_old?
-      gcc_version("gcc") < OS::LINUX_GCC_CI_VERSION
+      gcc_version("/usr/bin/gcc") < OS::LINUX_GCC_CI_VERSION
     end
 
     sig { returns(T::Hash[String, T.nilable(String)]) }

Library/Homebrew/extend/os/linux/install.rb

@@ -38,13 +38,13 @@ module Homebrew
     def perform_preinstall_checks(all_fatal: false, cc: nil)
       generic_perform_preinstall_checks(all_fatal: all_fatal, cc: cc)
       symlink_ld_so
-      symlink_gcc_libs
+      setup_preferred_gcc_libs
     end
 
     def global_post_install
       generic_global_post_install
       symlink_ld_so
-      symlink_gcc_libs
+      setup_preferred_gcc_libs
     end
 
     def check_cpu
@@ -64,36 +64,71 @@ module Homebrew
 
     def symlink_ld_so
       brew_ld_so = HOMEBREW_PREFIX/"lib/ld.so"
-      return if brew_ld_so.readable?
 
-      ld_so = HOMEBREW_PREFIX/"opt/glibc/lib/ld-linux-x86-64.so.2"
+      ld_so = HOMEBREW_PREFIX/"opt/glibc/bin/ld.so"
       unless ld_so.readable?
         ld_so = DYNAMIC_LINKERS.find { |s| File.executable? s }
-        raise "Unable to locate the system's dynamic linker" unless ld_so
+        if ld_so.blank?
+          raise "Unable to locate the system's dynamic linker" unless brew_ld_so.readable?
+
+          return
+        end
       end
 
+      return if brew_ld_so.readable? && (brew_ld_so.readlink == ld_so)
+
       FileUtils.mkdir_p HOMEBREW_PREFIX/"lib"
       FileUtils.ln_sf ld_so, brew_ld_so
     end
     private_class_method :symlink_ld_so
 
-    def symlink_gcc_libs
+    def setup_preferred_gcc_libs
       gcc_opt_prefix = HOMEBREW_PREFIX/"opt/#{OS::LINUX_PREFERRED_GCC_RUNTIME_FORMULA}"
+      glibc_installed = (HOMEBREW_PREFIX/"opt/glibc/bin/ld.so").readable?
+
+      return unless gcc_opt_prefix.readable?
+
+      if glibc_installed
+        ld_so_conf_d = HOMEBREW_PREFIX/"etc/ld.so.conf.d"
+        unless ld_so_conf_d.exist?
+          ld_so_conf_d.mkpath
+          FileUtils.chmod "go-w", ld_so_conf_d
+        end
+
+        # Add gcc to ld search paths
+        ld_gcc_conf = ld_so_conf_d/"50-homebrew-preferred-gcc.conf"
+        unless ld_gcc_conf.exist?
+          ld_gcc_conf.atomic_write <<~EOS
+            # This file is generated by Homebrew. Do not modify.
+            #{gcc_opt_prefix}/lib/gcc/#{PREFERRED_GCC_RUNTIME_VERSION}
+          EOS
+          FileUtils.chmod "u=rw,go-wx", ld_gcc_conf
+
+          FileUtils.rm_f HOMEBREW_PREFIX/"etc/ld.so.cache"
+          system HOMEBREW_PREFIX/"opt/glibc/sbin/ldconfig"
+        end
+      else
+        odie "#{HOMEBREW_PREFIX}/lib does not exist!" unless (HOMEBREW_PREFIX/"lib").readable?
+      end
 
       GCC_RUNTIME_LIBS.each do |library|
-        gcc_library = gcc_opt_prefix/"lib/gcc/#{PREFERRED_GCC_RUNTIME_VERSION}/#{library}"
         gcc_library_symlink = HOMEBREW_PREFIX/"lib/#{library}"
-        # Skip if the link target doesn't exist.
-        next unless gcc_library.readable?
 
-        # Also skip if the symlink already exists.
+        if glibc_installed
-        next if gcc_library_symlink.readable? && (gcc_library_symlink.readlink == gcc_library)
+          # Remove legacy symlinks
+          FileUtils.rm gcc_library_symlink if gcc_library_symlink.symlink?
+        else
+          gcc_library = gcc_opt_prefix/"lib/gcc/#{PREFERRED_GCC_RUNTIME_VERSION}/#{library}"
+          # Skip if the link target doesn't exist.
+          next unless gcc_library.readable?
 
-        odie "#{HOMEBREW_PREFIX}/lib does not exist!" unless (HOMEBREW_PREFIX/"lib").readable?
+          # Also skip if the symlink already exists.
+          next if gcc_library_symlink.readable? && (gcc_library_symlink.readlink == gcc_library)
 
-        FileUtils.ln_sf gcc_library, gcc_library_symlink
+          FileUtils.ln_sf gcc_library, gcc_library_symlink
+        end
       end
     end
-    private_class_method :symlink_gcc_libs
+    private_class_method :setup_preferred_gcc_libs
   end
 end