Clear error_code on entry in win32_unicode_path constructor

include/boost/beast/core/detail/win32_unicode_path.hpp

@@ -29,6 +29,7 @@ class win32_unicode_path
 
 public:
     win32_unicode_path(const char* utf8_path, error_code& ec) {
+        ec = {};
         int ret = mb2wide(utf8_path, static_buf_.data(),
             static_buf_.size());
         if (ret == 0)

include/boost/beast/core/impl/file_posix.ipp

@@ -288,12 +288,13 @@ read(void* buffer, std::size_t n, error_code& ec) const
         if(result == 0)
         {
             // short read
-            return nread;
+            break;
         }
         n -= result;
         nread += result;
         buffer = static_cast<char*>(buffer) + result;
     }
+    ec = {};
     return nread;
 }
 
@@ -328,6 +329,7 @@ write(void const* buffer, std::size_t n, error_code& ec)
         nwritten += result;
         buffer = static_cast<char const*>(buffer) + result;
     }
+    ec = {};
     return nwritten;
 }
 

include/boost/beast/core/impl/file_stdio.ipp

@@ -300,6 +300,7 @@ read(void* buffer, std::size_t n, error_code& ec) const
         ec.assign(errno, generic_category());
         return 0;
     }
+    ec = {};
     return nread;
 }
 
@@ -318,6 +319,7 @@ write(void const* buffer, std::size_t n, error_code& ec)
         ec.assign(errno, generic_category());
         return 0;
     }
+    ec = {};
     return nwritten;
 }
 

test/beast/core/file_test.hpp

@@ -445,6 +445,80 @@ test_file()
     }
 
     BEAST_EXPECT(! fs::exists(path));
+    {
+        string_view const s = "Hello, world!";
+
+        {
+            File f;
+            error_code ec = make_error_code(errc::no_such_file_or_directory);
+            f.open(path, file_mode::write, ec);
+            BEAST_EXPECT(! ec);
+        }
+
+        {
+            File f;
+            error_code ec;
+            f.open(path, file_mode::write, ec);
+            BEAST_EXPECT(! ec);
+            ec = make_error_code(errc::no_such_file_or_directory);
+            f.write(s.data(), s.size(), ec);
+            BEAST_EXPECT(! ec);
+        }
+
+        {
+            File f;
+            error_code ec;
+            f.open(path, file_mode::read, ec);
+            BEAST_EXPECT(! ec);
+            ec = make_error_code(errc::no_such_file_or_directory);
+            f.size(ec);
+            BEAST_EXPECT(! ec);
+        }
+
+        {
+            File f;
+            error_code ec;
+            f.open(path, file_mode::read, ec);
+            BEAST_EXPECT(! ec);
+            ec = make_error_code(errc::no_such_file_or_directory);
+            f.pos(ec);
+            BEAST_EXPECT(! ec);
+        }
+
+        {
+            File f;
+            error_code ec;
+            f.open(path, file_mode::read, ec);
+            BEAST_EXPECT(! ec);
+            ec = make_error_code(errc::no_such_file_or_directory);
+            f.seek(0, ec);
+            BEAST_EXPECT(! ec);
+        }
+
+        {
+            File f;
+            error_code ec;
+            f.open(path, file_mode::read, ec);
+            BEAST_EXPECT(! ec);
+            std::string buf;
+            buf.resize(s.size());
+            ec = make_error_code(errc::no_such_file_or_directory);
+            f.read(&buf[0], buf.size(), ec);
+            BEAST_EXPECT(! ec);
+        }
+
+        {
+            File f;
+            error_code ec;
+            f.open(path, file_mode::read, ec);
+            BEAST_EXPECT(! ec);
+            ec = make_error_code(errc::no_such_file_or_directory);
+            f.close(ec);
+            BEAST_EXPECT(! ec);
+        }
+
+        remove(path);
+    }
 }
 
 } // beast

tools/get-boost.sh

@@ -82,6 +82,7 @@ git submodule update --init --depth 20 --jobs 4 \
     libs/ratio \
     libs/rational \
     libs/regex \
+    libs/static_assert \
     libs/thread \
     libs/tuple \
     libs/type_index \