read_symlink: return missing if not symlink

Author: scivision

+stdlib/+dotnet/read_symlink.m

@@ -9,7 +9,7 @@
   % on Unix, this can be empty if the file is not a symlink
 catch e
   dotnetException(e)
-  r = string.empty;
+  r = missing;
 end
 
 end

+stdlib/+java/read_symlink.m

@@ -11,7 +11,7 @@
   r = string(javaMethod('readSymbolicLink', 'java.nio.file.Files', p));
 catch e
   javaException(e)
-  r = string.empty;
+  r = missing;
 end
 
 end

+stdlib/+native/read_symlink.m

@@ -1,12 +1,9 @@
 function r = read_symlink(file)
 
-if ~stdlib.matlabOlderThan('R2024b')
-  [ok, r] = isSymbolicLink(file);
-  if ~ok
-    r = string.empty;
-  end
+if stdlib.matlabOlderThan('R2024b')
+  r = missing;
 else
-  r = string.empty;
+  [~, r] = isSymbolicLink(file);
 end
 
 end

+stdlib/+python/read_symlink.m

@@ -1,6 +1,6 @@
 function r = read_symlink(file)
 
-r = string.empty;
+r = missing;
 
 try
   p = py.pathlib.Path(file);

+stdlib/+shell/read_symlink.m

@@ -1,6 +1,6 @@
 function [r, cmd] = read_symlink(file)
 
-r = string.empty;
+r = missing;
 
 if isunix()
   cmd = sprintf('readlink -fn "%s"', file);

+stdlib/read_symlink.m

@@ -16,7 +16,7 @@
   backend (1,:) string = ["native", "java", "python", "dotnet", "shell"]
 end
 
-r = string.empty;
+r = missing;
 
 for b = backend
   switch b
@@ -36,7 +36,7 @@
       error('stdlib:read_symlink:ValueError', 'Unknown backend: %s', b)
   end
 
-  if ~isempty(r)
+  if ~ismissing(r)
     return
   end
 end

+stdlib/toolbox_used.m

@@ -30,7 +30,7 @@
 
 if ispc()
   old = getenv('KMP_DUPLICATE_LIB_OK');
-  setenv('KMP_DUPLICATE_LIB_OK', 'TRUE');
+  setenv('KMP_DUPLICATE_LIB_OK', 'TRUE')
 
   % otherwise,
   %   matlab -batch "buildtool test"

test/TestSymlink.m

@@ -55,12 +55,12 @@ function test_read_symlink_not_symlink(tc, Pre)
 
 function test_read_symlink(tc, B_is_symlink)
 r = stdlib.read_symlink(tc.link, B_is_symlink);
-tc.verifyClass(r, 'string')
 
 if ismember(B_is_symlink, stdlib.Backend().select('read_symlink'))
+  tc.verifyClass(r, 'string')
   tc.verifyEqual(r, string(tc.target))
 else
-  tc.verifyEmpty(r)
+  tc.verifyTrue(ismissing(r))
 end
 end