Use shorter symlink by real paths

Author: nobu

lib/fileutils.rb

@@ -732,19 +732,31 @@ def ln_sf(src, dest, noop: nil, verbose: nil)
   #
   def ln_sr(src, dest, target_directory: true, force: nil, noop: nil, verbose: nil)
     cmd = "ln -s#{force ? 'f' : ''}#{target_directory ? '' : 'T'}" if verbose
-    unless target_directory
-      destdirs = fu_split_path(dest)
-    end
     fu_each_src_dest0(src, dest, target_directory) do |s,d|
       if target_directory
-        destdirs = fu_split_path(File.dirname(d))
-      # else d == dest
+        parent = File.dirname(d)
+        destdirs = fu_split_path(parent)
+        real_ddirs = fu_split_path(File.realpath(parent))
+      else
+        destdirs ||= fu_split_path(dest)
+        real_ddirs ||= fu_split_path(File.realpath(dest))
       end
       srcdirs = fu_split_path(s)
       i = fu_common_components(srcdirs, destdirs)
       n = destdirs.size - i
       n -= 1 unless target_directory
-      s = File.join(fu_clean_components(*Array.new(n, '..'), *srcdirs[i..-1]))
+      link1 = fu_clean_components(*Array.new([n, 0].max, '..'), *srcdirs[i..-1])
+      begin
+        real_sdirs = fu_split_path(File.realdirpath(s)) rescue nil
+      rescue
+      else
+        i = fu_common_components(real_sdirs, real_ddirs)
+        n = real_ddirs.size - i
+        n -= 1 unless target_directory
+        link2 = fu_clean_components(*Array.new([n, 0].max, '..'), *real_sdirs[i..-1])
+        link1 = link2 if link1.size > link2.size
+      end
+      s = File.join(link1)
       fu_output_message [cmd, s, d].flatten.join(' ') if verbose
       next if noop
       remove_file d, true if force

test/fileutils/test_fileutils.rb

@@ -1031,7 +1031,8 @@ def test_ln_sr
     assert_all_assertions_foreach(nil, *TARGETS) do |fname|
       lnfname = 'tmp/lnsdest'
       ln_sr fname, lnfname
-      assert FileTest.symlink?(lnfname), 'not symlink'
+      assert_file.symlink?(lnfname)
+      assert_file.identical?(lnfname, fname)
       assert_equal "../#{fname}", File.readlink(lnfname)
     ensure
       rm_f lnfname
@@ -1060,6 +1061,7 @@ def test_ln_sr
     ln_sr 'tmp/src/xxx', 'data'
     assert_file.symlink?('data/xxx')
     assert_equal 'ok', File.read('data/xxx')
+    assert_equal 'src/xxx', File.readlink('data/xxx')
   end
 
   def test_ln_sr_not_target_directory