From 19a117889c2db6b817af9458c04c04f324162e75 Mon Sep 17 00:00:00 2001
From: Stefan Boberg <stefan.boberg@epicgames.com>
Date: Mon, 9 Mar 2026 10:50:47 +0100
Subject: Eliminate spdlog dependency (#773)

Removes the vendored spdlog library (~12,000 lines) and replaces it with a purpose-built logging system in zencore (~1,800 lines). The new implementation provides the same functionality with fewer abstractions, no shared_ptr overhead, and full control over the logging pipeline.

### What changed

**New logging core in zencore/logging/:**
- LogMessage, Formatter, Sink, Logger, Registry - core abstractions matching spdlog's model but simplified
- AnsiColorStdoutSink - ANSI color console output (replaces spdlog stdout_color_sink)
- MsvcSink - OutputDebugString on Windows (replaces spdlog msvc_sink)
- AsyncSink - async logging via BlockingQueue worker thread (replaces spdlog async_logger)
- NullSink, MessageOnlyFormatter - utility types
- Thread-safe timestamp caching in formatters using RwLock

**Moved to zenutil/logging/:**
- FullFormatter - full log formatting with timestamp, logger name, level, source location, multiline alignment
- JsonFormatter - structured JSON log output
- RotatingFileSink - rotating file sink with atomic size tracking

**API changes:**
- Log levels are now an enum (LogLevel) instead of int, eliminating the zen::logging::level namespace
- LoggerRef no longer wraps shared_ptr - it holds a raw pointer with the registry owning lifetime
- Logger error handler is wired through Registry and propagated to all loggers on registration
- Logger::Log() now populates ThreadId on every message

**Cleanup:**
- Deleted thirdparty/spdlog/ entirely (110+ files)
- Deleted full_test_formatter (was ~80% duplicate of FullFormatter)
- Renamed snake_case classes to PascalCase (full_formatter -> FullFormatter, json_formatter -> JsonFormatter, sentry_sink -> SentrySink)
- Removed spdlog from xmake dependency graph

### Build / test impact

- zencore no longer depends on spdlog
- zenutil and zenvfs xmake.lua updated to drop spdlog dep
- zentelemetry xmake.lua updated to drop spdlog dep
- All existing tests pass, no test changes required beyond formatter class renames
---
 thirdparty/spdlog/tests/test_macros.cpp | 53 ---------------------------------
 1 file changed, 53 deletions(-)
 delete mode 100644 thirdparty/spdlog/tests/test_macros.cpp

(limited to 'thirdparty/spdlog/tests/test_macros.cpp')

diff --git a/thirdparty/spdlog/tests/test_macros.cpp b/thirdparty/spdlog/tests/test_macros.cpp
deleted file mode 100644
index 132706f13..000000000
--- a/thirdparty/spdlog/tests/test_macros.cpp
+++ /dev/null
@@ -1,53 +0,0 @@
-/*
- * This content is released under the MIT License as specified in
- * https://raw.githubusercontent.com/gabime/spdlog/master/LICENSE
- */
-
-#include "includes.h"
-
-#if SPDLOG_ACTIVE_LEVEL != SPDLOG_LEVEL_DEBUG
-    #error "Invalid SPDLOG_ACTIVE_LEVEL in test. Should be SPDLOG_LEVEL_DEBUG"
-#endif
-
-#define TEST_FILENAME "test_logs/simple_log"
-
-TEST_CASE("debug and trace w/o format string", "[macros]") {
-    prepare_logdir();
-    spdlog::filename_t filename = SPDLOG_FILENAME_T(TEST_FILENAME);
-
-    auto logger = spdlog::create<spdlog::sinks::basic_file_sink_mt>("logger", filename);
-    logger->set_pattern("%v");
-    logger->set_level(spdlog::level::trace);
-
-    SPDLOG_LOGGER_TRACE(logger, "Test message 1");
-    SPDLOG_LOGGER_DEBUG(logger, "Test message 2");
-    logger->flush();
-
-    using spdlog::details::os::default_eol;
-    REQUIRE(ends_with(file_contents(TEST_FILENAME),
-                      spdlog::fmt_lib::format("Test message 2{}", default_eol)));
-    REQUIRE(count_lines(TEST_FILENAME) == 1);
-
-    auto orig_default_logger = spdlog::default_logger();
-    spdlog::set_default_logger(logger);
-
-    SPDLOG_TRACE("Test message 3");
-    SPDLOG_DEBUG("Test message {}", 4);
-    logger->flush();
-
-    require_message_count(TEST_FILENAME, 2);
-    REQUIRE(ends_with(file_contents(TEST_FILENAME),
-                      spdlog::fmt_lib::format("Test message 4{}", default_eol)));
-    spdlog::set_default_logger(std::move(orig_default_logger));
-}
-
-TEST_CASE("disable param evaluation", "[macros]") {
-    SPDLOG_TRACE("Test message {}", throw std::runtime_error("Should not be evaluated"));
-}
-
-TEST_CASE("pass logger pointer", "[macros]") {
-    auto logger = spdlog::create<spdlog::sinks::null_sink_mt>("refmacro");
-    auto &ref = *logger;
-    SPDLOG_LOGGER_TRACE(&ref, "Test message 1");
-    SPDLOG_LOGGER_DEBUG(&ref, "Test message 2");
-}
-- 
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