Merge pull request #1330 from Homebrew/vscode-uid

vscode_extension_installer: use UID for installs

lib/bundle/vscode_extension_installer.rb

@@ -24,13 +24,39 @@ def preinstall(name, no_upgrade: false, verbose: false)
       true
     end
 
+    def exchange_uid(&block)
+      euid = Process.euid
+      uid = Process.uid
+      return yield if euid == uid
+
+      old_euid = euid
+      process_reexchangeable = Process::UID.re_exchangeable?
+      if process_reexchangeable
+        Process::UID.re_exchange
+      else
+        Process::Sys.seteuid(uid)
+      end
+
+      return_value = with_env("HOME" => Etc.getpwuid(Process.uid).dir, &block)
+
+      if process_reexchangeable
+        Process::UID.re_exchange
+      else
+        Process::Sys.seteuid(old_euid)
+      end
+
+      return_value
+    end
+
     def install(name, preinstall: true, no_upgrade: false, verbose: false, force: false)
       return true unless preinstall
       return true if extension_installed?(name)
 
       puts "Installing #{name} VSCode extension. It is not currently installed." if verbose
 
-      return false unless Bundle.system "code", "--install-extension", name, verbose: verbose
+      return false unless exchange_uid do
+        Bundle.system("code", "--install-extension", name, verbose:)
+      end
 
       installed_extensions << name
 

spec/bundle/vscode_extension_installer_spec.rb

@@ -1,6 +1,7 @@
 # frozen_string_literal: true
 
 require "spec_helper"
+require "extend/kernel"
 
 describe Bundle::VscodeExtensionInstaller do
   context "when VSCode is not installed" do
@@ -48,6 +49,26 @@
         expect(described_class.preinstall("foo")).to be(true)
         expect(described_class.install("foo")).to be(true)
       end
+
+      it "installs extension when euid != uid and Process::UID.re_exchangeable? returns true" do
+        expect(Process).to receive(:euid).and_return(1).once
+        expect(Process::UID).to receive(:re_exchangeable?).and_return(true).once
+        expect(Process::UID).to receive(:re_exchange).twice
+
+        expect(Bundle).to receive(:system).with("code", "--install-extension", "foo", verbose: false).and_return(true)
+        expect(described_class.preinstall("foo")).to be(true)
+        expect(described_class.install("foo")).to be(true)
+      end
+
+      it "installs extension when euid != uid and Process::UID.re_exchangeable? returns false" do
+        expect(Process).to receive(:euid).and_return(1).once
+        expect(Process::UID).to receive(:re_exchangeable?).and_return(false).once
+        expect(Process::Sys).to receive(:seteuid).twice
+
+        expect(Bundle).to receive(:system).with("code", "--install-extension", "foo", verbose: false).and_return(true)
+        expect(described_class.preinstall("foo")).to be(true)
+        expect(described_class.install("foo")).to be(true)
+      end
     end
   end
 end

spec/stub/extend/kernel.rb

@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+module Kernel
+  def with_env(_hash)
+    yield if block_given?
+  end
+end