Userland+Tests: Convert File::read_link() from String to ErrorOr<String>

This converts the return value of File::read_link() from String to
ErrorOr<String>.

The rest of the change is to support the potential of an Error being
returned and subsequent release of the value when no Error is returned.
Unfortunately at this stage none of the places affected can utililize
our TRY() macro.

1 files changed, 8 insertions, 2 deletions

diff --git a/Tests/LibC/TestLibCMkTemp.cpp b/Tests/LibC/TestLibCMkTemp.cpp
index 5045640a86..03d377642b 100644
--- a/Tests/LibC/TestLibCMkTemp.cpp
+++ b/Tests/LibC/TestLibCMkTemp.cpp
@@ -86,7 +86,10 @@ TEST_CASE(test_mkstemp_unique_filename)
         auto fd = mkstemp(path);
         EXPECT_NE(fd, -1);
 
-        auto temp_path = Core::File::read_link(String::formatted("/proc/{}/fd/{}", getpid(), fd));
+        auto temp_path_or_error = Core::File::read_link(String::formatted("/proc/{}/fd/{}", getpid(), fd));
+        EXPECT(!temp_path_or_error.is_error());
+
+        auto temp_path = temp_path_or_error.release_value();
         EXPECT(temp_path.characters());
 
         close(fd);
@@ -104,7 +107,10 @@ TEST_CASE(test_mkstemp_unique_filename)
         auto fd = mkstemp(path);
         EXPECT(fd != -1);
 
-        auto path2 = Core::File::read_link(String::formatted("/proc/{}/fd/{}", getpid(), fd));
+        auto path2_or_error = Core::File::read_link(String::formatted("/proc/{}/fd/{}", getpid(), fd));
+        EXPECT(!path2_or_error.is_error());
+
+        auto path2 = path2_or_error.release_value();
         EXPECT(path2.characters());
 
         close(fd);