read_symlink: no posix, use missing

Author: scivision

+stdlib/read_symlink.m

@@ -7,31 +7,27 @@
   p {mustBeTextScalar}
 end
 
-r = "";
 
 try
-  [ok, t] = isSymbolicLink(p);
-  if ~ok, return, end
+  [~, r] = isSymbolicLink(p);
 catch e
   switch e.identifier
-    case "Octave:undefined-function", t = readlink(p);
+    case "Octave:undefined-function", r = readlink(p);
     case "MATLAB:UndefinedFunction"
-      if ~stdlib.is_symlink(p)
-        return
+      if stdlib.is_symlink(p)
+        % must be absolute path
+        % must not be .canonical or symlink is gobbled!
+        r = stdlib.absolute(p, "", false);
+
+        % https://docs.oracle.com/en/java/javase/21/docs/api/java.base/java/nio/file/Files.html#readSymbolicLink(java.nio.file.Path)
+        r = java.nio.file.Files.readSymbolicLink(javaPathObject(r)).string;
+      else
+        r = string(missing);
       end
-
-      % must be absolute path
-      % must not be .canonical or symlink is gobbled!
-      r = stdlib.absolute(p, "", false);
-
-      % https://docs.oracle.com/en/java/javase/21/docs/api/java.base/java/nio/file/Files.html#readSymbolicLink(java.nio.file.Path)
-      t = java.nio.file.Files.readSymbolicLink(javaPathObject(r));
     otherwise, rethrow(e)
   end
 end
 
-r = stdlib.posix(t);
-
 end
 
 %!test

test/TestSymlink.m

@@ -17,9 +17,9 @@ function setup_symlink(tc)
 
 tc.tempDir = tc.createTemporaryFolder();
 
-tc.link = tc.tempDir + "/my.lnk";
+tc.link = fullfile(tc.tempDir, "my.lnk");
 
-tc.target = stdlib.posix(mfilename("fullpath") + ".m");
+tc.target = mfilename("fullpath") + ".m";
 
 tc.assumeTrue(stdlib.create_symlink(tc.target, tc.link), ...
     "failed to create test link " + tc.link)
@@ -36,10 +36,11 @@ function test_is_symlink(tc, p)
 
 
 function test_read_symlink(tc)
+import matlab.unittest.constraints.HasMissing
 
-tc.verifyEqual(stdlib.read_symlink(""), "")
-tc.verifyEqual(stdlib.read_symlink("not-exist"), "")
-tc.verifyEqual(stdlib.read_symlink(tc.target), "")
+tc.verifyThat(stdlib.read_symlink(""), HasMissing)
+tc.verifyThat(stdlib.read_symlink("not-exist"), HasMissing)
+tc.verifyThat(stdlib.read_symlink(tc.target), HasMissing)
 
 t = stdlib.read_symlink(tc.link);
 tc.verifyNotEmpty(t)