fix(relinker): report buffered output write failures

core/relinker/CMakeLists.txt

@@ -106,6 +106,19 @@ endif()
 
 
 if(BUILD_TESTING)
+    if(CMAKE_SYSTEM_NAME STREQUAL "Linux")
+        add_executable(file_writer_tests
+            ${CMAKE_CURRENT_SOURCE_DIR}/io/tests/FileWriterTests.cpp
+            ${CMAKE_CURRENT_SOURCE_DIR}/io/src/FileWriter.cpp
+        )
+        target_include_directories(file_writer_tests PRIVATE
+            ${CMAKE_CURRENT_SOURCE_DIR}/domain/include
+            ${CMAKE_CURRENT_SOURCE_DIR}/io/include
+        )
+        add_test(NAME file_writer_binary COMMAND file_writer_tests binary)
+        add_test(NAME file_writer_text COMMAND file_writer_tests text)
+    endif()
+
     add_executable(amd64_only_converter_tests
         ${CMAKE_CURRENT_SOURCE_DIR}/codegen/tests/Amd64OnlyConverterTests.cpp
         ${CMAKE_CURRENT_SOURCE_DIR}/codegen/src/Amd64OnlyConverter.cpp

core/relinker/io/src/FileWriter.cpp

@@ -9,6 +9,7 @@ void FileWriter::Write(const std::string& path, const std::vector<std::uint8_t>&
     if (!f)
         throw Domain::RelinkerException("Cannot open output file: " + path);
     f.write(reinterpret_cast<const char*>(data.data()), static_cast<std::streamsize>(data.size()));
+    f.close();
     if (!f)
         throw Domain::RelinkerException("Failed to write file: " + path);
 }
@@ -18,6 +19,7 @@ void FileWriter::Write(const std::string& path, const std::string& content) {
     if (!f)
         throw Domain::RelinkerException("Cannot open output file: " + path);
     f << content;
+    f.close();
     if (!f)
         throw Domain::RelinkerException("Failed to write file: " + path);
 }

core/relinker/io/tests/FileWriterTests.cpp

@@ -0,0 +1,43 @@
+#include <io/FileWriter.hpp>
+#include <domain/Types.hpp>
+#include <iostream>
+#include <stdexcept>
+#include <string>
+#include <vector>
+
+namespace {
+
+template<typename TValue>
+void requireWriteFailure(const TValue& data) {
+    Io::FileWriter writer;
+    writer.Write("/dev/null", data);
+    try {
+        writer.Write("/dev/full", data);
+    } catch (const Domain::RelinkerException& e) {
+        if (std::string(e.what()) != "Failed to write file: /dev/full")
+            throw std::runtime_error("Unexpected write failure: " + std::string(e.what()));
+        return;
+    }
+    throw std::runtime_error("Write to /dev/full reported success");
+}
+
+}
+
+int main(int argc, char* argv[]) {
+    try {
+        if (argc != 2) throw std::runtime_error("Expected binary or text");
+        const std::string mode = argv[1];
+        for (const std::size_t size : {std::size_t{3}, std::size_t{65536}}) {
+            if (mode == "binary")
+                requireWriteFailure(std::vector<std::uint8_t>(size, 0x41));
+            else if (mode == "text")
+                requireWriteFailure(std::string(size, 'A'));
+            else
+                throw std::runtime_error("Unknown test mode: " + mode);
+        }
+    } catch (const std::exception& e) {
+        std::cerr << e.what() << '\n';
+        return 1;
+    }
+    return 0;
+}