[GR-18163] Process.euid= should accept String (#2651)

PullRequest: truffleruby/3344

Author: eregon

CHANGELOG.md

@@ -25,6 +25,7 @@ Compatibility:
 * Implement `rb_imemo_tmpbuf` allocation for `ripper` (@aardvark179).
 * Implement `inherit` argument for `Module#class_variables` (#2653, @bjfish).
 * Fix `Float#/` when dividing by `Rational` (@bjfish).
+* `Process.euid=` should accept String (#2615, @ngtban).
 
 Performance:
 

spec/ruby/core/process/euid_spec.rb

@@ -21,6 +21,16 @@
       -> { Process.euid = Object.new }.should raise_error(TypeError)
     end
 
+    it "sets the effective user id to its own uid if given the username corresponding to its own uid" do
+      raise unless Process.uid == Process.euid
+
+      require "etc"
+      user = Etc.getpwuid(Process.uid).name
+
+      Process.euid = user
+      Process.euid.should == Process.uid
+    end
+
     as_user do
       it "raises Errno::ERPERM if run by a non superuser trying to set the superuser id" do
         -> { (Process.euid = 0)}.should raise_error(Errno::EPERM)

src/main/ruby/truffleruby/core/process.rb

@@ -403,7 +403,14 @@ def self.euid=(uid)
     # the 4 rescue clauses below are needed
     # until respond_to? can be used to query the implementation of methods attached via FFI
     # atm respond_to returns true if a method is attached but not implemented on the platform
-    uid = Truffle::Type.coerce_to uid, Integer, :to_int
+    uid =
+      if uid.kind_of?(String)
+        require 'etc'
+        Etc.getpwnam(uid).uid
+      else
+        Truffle::Type.coerce_to uid, Integer, :to_int
+      end
+
     begin
       ret = Truffle::POSIX.setresuid(-1, uid, -1)
     rescue NotImplementedError