[libcxx-commits] [libcxx] [libc++][filesystem] Applied `[[nodiscard]]` (PR #171085)

[A. Jiang via libcxx-commits]

================
@@ -6,13 +6,449 @@
 //
 //===----------------------------------------------------------------------===//
 
-// UNSUPPORTED: c++03, c++11, c++14
+// REQUIRES: std-at-least-c++17
 
-// check that <filesystem> functions are marked [[nodiscard]]
+// UNSUPPORTED: no-filesystem
+
+// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
+
+// <filesystem>
+
+// Check that functions are marked [[nodiscard]]
 
 #include <filesystem>
+#include <string>
+#include <string_view>
+
+#include "test_macros.h"
 
 void test() {
-  std::filesystem::path path;
-  path.empty(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  {
+    const auto op = std::filesystem::copy_options::none;
+
+    op & op; // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+    op | op; // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+    op ^ op; // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+    ~op;     // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  }
+
+  {
+    const std::filesystem::directory_entry de;
+    std::error_code ec;
+
+    de.path(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+    de.exists();   // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+    de.exists(ec); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+    de.is_block_file();   // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+    de.is_block_file(ec); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    de.is_character_file();
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    de.is_character_file(ec);
+
+    de.is_directory();   // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+    de.is_directory(ec); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+    de.is_fifo();   // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+    de.is_fifo(ec); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+    de.is_other();   // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+    de.is_other(ec); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    de.is_regular_file();
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    de.is_regular_file(ec);
+
+    de.is_socket();   // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+    de.is_socket(ec); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+    de.is_symlink();   // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+    de.is_symlink(ec); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+    de.file_size();   // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+    de.file_size(ec); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    de.hard_link_count();
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    de.hard_link_count(ec);
+
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    de.last_write_time();
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    de.last_write_time(ec);
+
+    de.status();   // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+    de.status(ec); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+    de.symlink_status();   // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+    de.symlink_status(ec); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  }
+
+  {
+    const std::filesystem::directory_iterator di;
+
+    *di; // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    std::filesystem::begin(di);
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    std::filesystem::end(di);
+  }
+
+  {
+    const auto op = std::filesystem::directory_options::none;
+
+    op & op; // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+    op | op; // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+    op ^ op; // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+    ~op;     // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  }
+
+  {
+    const std::filesystem::file_status fs;
+
+    fs.type();        // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+    fs.permissions(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  }
+
+  {
+    std::error_code ec;
+    const std::filesystem::filesystem_error fs("zmt", ec);
+
+    fs.path1(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+    fs.path2(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+    fs.what(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  }
+
+  {
+    const std::filesystem::path p;
+    std::error_code ec;
+    const std::filesystem::file_status fs;
+
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    std::filesystem::absolute(p);
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    std::filesystem::absolute(p, ec);
+
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    std::filesystem::canonical(p);
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    std::filesystem::canonical(p, ec);
+
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    std::filesystem::current_path();
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    std::filesystem::current_path(ec);
+
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    std::filesystem::equivalent(p, p);
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    std::filesystem::equivalent(p, p, ec);
+
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    std::filesystem::status_known(fs);
+
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    std::filesystem::exists(fs);
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    std::filesystem::exists(p);
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    std::filesystem::exists(p, ec);
+
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    std::filesystem::file_size(p);
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    std::filesystem::file_size(p, ec);
+
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    std::filesystem::hard_link_count(p);
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    std::filesystem::hard_link_count(p, ec);
+
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    std::filesystem::is_block_file(fs);
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    std::filesystem::is_block_file(p);
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    std::filesystem::is_block_file(p, ec);
+
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    std::filesystem::is_character_file(fs);
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    std::filesystem::is_character_file(p);
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    std::filesystem::is_character_file(p, ec);
+
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    std::filesystem::is_directory(fs);
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    std::filesystem::is_directory(p);
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    std::filesystem::is_directory(p, ec);
+
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    std::filesystem::is_empty(p);
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    std::filesystem::is_empty(p, ec);
+
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    std::filesystem::is_fifo(fs);
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    std::filesystem::is_fifo(p);
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    std::filesystem::is_fifo(p, ec);
+
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    std::filesystem::is_regular_file(fs);
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    std::filesystem::is_regular_file(p);
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    std::filesystem::is_regular_file(p, ec);
+
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    std::filesystem::is_symlink(fs);
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    std::filesystem::is_symlink(p);
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    std::filesystem::is_symlink(p, ec);
+
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    std::filesystem::is_other(fs);
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    std::filesystem::is_other(p);
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    std::filesystem::is_other(p, ec);
+
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    std::filesystem::is_socket(fs);
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    std::filesystem::is_socket(p);
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    std::filesystem::is_socket(p, ec);
+
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    std::filesystem::last_write_time(p);
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    std::filesystem::last_write_time(p, ec);
+
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    std::filesystem::proximate(p, p, ec);
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    std::filesystem::proximate(p, ec);
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    std::filesystem::proximate(p);
+
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    std::filesystem::read_symlink(p);
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    std::filesystem::read_symlink(p, ec);
+
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    std::filesystem::relative(p, p, ec);
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    std::filesystem::relative(p, ec);
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    std::filesystem::relative(p);
+
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    std::filesystem::space(p);
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    std::filesystem::space(p, ec);
+
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    std::filesystem::status(p);
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    std::filesystem::status(p, ec);
+
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    std::filesystem::symlink_status(p);
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    std::filesystem::symlink_status(p, ec);
+
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    std::filesystem::temp_directory_path();
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    std::filesystem::temp_directory_path(ec);
+
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    std::filesystem::weakly_canonical(p);
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    std::filesystem::weakly_canonical(p, ec);
+  }
+
+  {
+    std::filesystem::path::iterator it;
+
+    *it; // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  }
+
+  {
+    std::filesystem::path p;
+    const std::string src;
+
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    p.native();
+
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    p.c_str();
+
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    p.string();
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    p.u8string();
+#if !defined(TEST_HAS_NO_LOCALIZATION)
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    p.string<char>();
+
+#  if !defined(TEST_HAS_NO_WIDE_CHARACTERS)
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    p.wstring();
+#  endif
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    p.u16string();
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    p.u32string();
+#endif // !defined(TEST_HAS_NO_LOCALIZATION)
+
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    p.generic_string();
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    p.generic_u8string();
+#if !defined(TEST_HAS_NO_LOCALIZATION)
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    p.generic_string<char>();
+
+#  if !defined(TEST_HAS_NO_WIDE_CHARACTERS)
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    p.generic_wstring();
+#  endif
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    p.generic_u16string();
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    p.generic_u32string();
+#endif // !defined(TEST_HAS_NO_LOCALIZATION)
+
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    p.compare(p);
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    p.compare(std::string{});
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    p.compare(std::string_view{});
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    p.compare("");
+
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    p.root_name();
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    p.root_directory();
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    p.root_path();
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    p.relative_path();
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    p.parent_path();
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    p.filename();
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    p.stem();
+
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    p.empty();
+
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    p.has_root_name();
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    p.has_root_directory();
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    p.has_root_path();
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    p.has_relative_path();
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    p.has_parent_path();
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    p.has_filename();
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    p.has_stem();
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    p.has_extension();
+
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    p.is_absolute();
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    p.is_relative();
+
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    p.lexically_normal();
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    p.lexically_relative(p);
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    p.lexically_proximate(p);
+
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    p.begin();
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    p.end();
+
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    std::filesystem::hash_value(p);
+
+    std::hash<std::filesystem::path> hash;
+
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    hash(p);
+  }
+
+  {
+    const auto op = std::filesystem::perm_options::add;
+
+    op & op; // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+    op | op; // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+    op ^ op; // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+    ~op;     // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  }
+
+  {
+    const auto op = std::filesystem::perms::all;
+
+    op & op; // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+    op | op; // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+    op ^ op; // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+    ~op;     // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+  }
+
+  {
+    const std::filesystem::recursive_directory_iterator it;
+
+    *it; // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+    it.options(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+    it.depth();   // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    it.recursion_pending();
+
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    std::filesystem::begin(it);
+    // expected-warning at +1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+    std::filesystem::end(it);
+  }
+
+  {
+    const std::string str;
+
+#if !defined(TEST_HAS_NO_LOCALIZATION)
----------------
frederick-vs-ja wrote:

No change requested as fixed should be in a future PR. This is quite weird. If localization is unavailable, we should use non-transcoded strings as-is, so IMO these uses of `u8path` should be always available. 

https://github.com/llvm/llvm-project/pull/171085