[libc++] [P1164] Add tests for create_directories. NFC.

[curdeius]

Summary

That's a follow-up patch after D92769.

[curdeius]

Regarding https://reviews.llvm.org/D92769#inline-868480. @mstorsjo

If parent does exist, but isn't a directory, the check if (not exists(parent_st)) above won't trigger, so it won't hit the case of calling __create_directory("parent_which_is_file"), but will instead call __create_directory("parent_which_is_file/subdir"). That call doesn't return the error code corresponding to EEXIST, but gives an error corresponding to no_such_file_or_directory/ENOENT instead.

By extending the check above into if (not exists(parent_st)) { ... } else if (!is_directory(parent)) return err.report(errc::file_exists);, one would get the more expected error code here too.

MS STL has indeed a special handling of errors while creating directories. See https://github.com/microsoft/STL/blob/68b344c9dcda6ddf1a8fca112cb9033f9e50e787/stl/inc/filesystem#L3766-L3777
I think we can do something similar indeed, so that the error that pops up is the error the one would expect.
I'll take a look at the tests they do and try to improve handling in libc++.

[curdeius]

• Check exact error codes.

[mstorsjo]

libcxx/test/std/input.output/filesystems/fs.op.funcs/fs.op.create_directories/create_directories.pass.cpp

110

Btw, the filesystem tests has got a helper function, that would allow writing this as ErrorIs(ec, std::errc::file_exists) - but I verified that this form also seems to work.

The thing is, that with MS STL, the returned error codes don't use the standard std::errc values and category, but wrap the windows native error codes. The ErrorIs() helper explicitly converts them to the generic error category (via ec.default_error_condition()) before comparing error values, but it looks like operator==() does the same as well, implicitly.

[curdeius]

• Mark macosx10.15 as XFAIL.
• Use ErrorIs.

[curdeius]

libcxx/test/std/input.output/filesystems/fs.op.funcs/fs.op.create_directories/create_directories.pass.cpp

110

Ok, I use ErrorIs now, even it doesn't change much. But it may be future proof.
Do you have a scenario where the returned error code would be unintuitive?

[mstorsjo]

libcxx/test/std/input.output/filesystems/fs.op.funcs/fs.op.create_directories/create_directories.pass.cpp

110

Not in libc++ itself, but MS STL produces such error codes (and I have a setup where I run the libc++ tests against MS STL).

libcxx/test/std/input.output/filesystems/fs.op.funcs/fs.op.create_directories/create_directories.pass.cpp

 //===----------------------------------------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // UNSUPPORTED: c++03
 
+// This test requires the dylib support introduced in D92769.
+// XFAIL: with_system_cxx_lib=macosx10.15
+
 // <filesystem>
 
 // bool create_directories(const path& p);
 // bool create_directories(const path& p, error_code& ec) noexcept;
 
 #include "filesystem_include.h"
 #include <type_traits>
 #include <cassert>
TEST_CASE(create_directory_symlinks) {
   const path root = env.create_dir("dir");
   const path sym_dest_dead = env.make_env_path("dead");
   const path dead_sym = env.create_directory_symlink(sym_dest_dead, "dir/sym_dir");
   const path target = env.make_env_path("dir/sym_dir/foo");
   {
     std::error_code ec = GetTestEC();
     TEST_CHECK(create_directories(target, ec) == false);
     TEST_CHECK(ec);
+    TEST_CHECK(ErrorIs(ec, std::errc::file_exists));
     TEST_CHECK(!exists(sym_dest_dead));
     TEST_CHECK(!exists(dead_sym));
   }
 }
 
-
 TEST_CASE(create_directory_through_symlinks) {
   scoped_test_env env;
   const path root = env.create_dir("dir");
   const path sym_dir = env.create_directory_symlink(root, "sym_dir");
   const path target = env.make_env_path("sym_dir/foo");
   const path resolved_target = env.make_env_path("dir/foo");
   TEST_REQUIRE(is_directory(sym_dir));
   {
     std::error_code ec = GetTestEC();
     TEST_CHECK(create_directories(target, ec) == true);
     TEST_CHECK(!ec);
     TEST_CHECK(is_directory(target));
     TEST_CHECK(is_directory(resolved_target));
   }
 }
 
+TEST_CASE(dest_is_file)
+{
+    scoped_test_env env;
+    const path file = env.create_file("file", 42);
+    std::error_code ec = GetTestEC();
+    TEST_CHECK(fs::create_directories(file, ec) == false);
+    TEST_CHECK(ec);
+    TEST_CHECK(ErrorIs(ec, std::errc::file_exists));
+    TEST_CHECK(is_regular_file(file));
+}
+
+TEST_CASE(dest_part_is_file)
+{
+    scoped_test_env env;
+    const path file = env.create_file("file");
+    const path dir = env.make_env_path("file/dir1");
+    std::error_code ec = GetTestEC();
+    TEST_CHECK(fs::create_directories(dir, ec) == false);
+    TEST_CHECK(ec);
+    TEST_CHECK(ErrorIs(ec, std::errc::not_a_directory));
+    TEST_CHECK(is_regular_file(file));
+    TEST_CHECK(!exists(dir));
+}
+
+TEST_CASE(dest_final_part_is_file)
+{
+    scoped_test_env env;
+    env.create_dir("dir");
+    const path file = env.create_file("dir/file");
+    const path dir = env.make_env_path("dir/file/dir1");
+    std::error_code ec = GetTestEC();
+    TEST_CHECK(fs::create_directories(dir, ec) == false);
+    TEST_CHECK(ec);
+    TEST_CHECK(ErrorIs(ec, std::errc::not_a_directory));
+    TEST_CHECK(is_regular_file(file));
+    TEST_CHECK(!exists(dir));
+}
+
 TEST_SUITE_END()