pw_log_null: Prevent asserts being routed to pw_log_null

pw_assert_log routes asserts to pw_log. If pw_log_null is in use, those asserts do nothing, which is dangerous. Similarly, a PW_LOG(PW_LOG_LEVEL_FATAL, ...) message does nothing with pw_log_null. Prevent fatal logs or asserts from doing nothing in pw_log_null by failing to compile. This is done by checking the log level in a static_assert. Note that this also prevents pw_log_null from working with non-constant log levels. Change-Id: I87d645115f5053ebad5127bda67b088a632ed562 Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/262853 Docs-Not-Needed: Wyatt Hepler <[email protected]> Presubmit-Verified: CQ Bot Account <[email protected]> Lint: Lint 🤖 <[email protected]> Pigweed-Auto-Submit: Wyatt Hepler <[email protected]> Commit-Queue: Auto-Submit <[email protected]> Reviewed-by: Dave Roth <[email protected]>
google · Feb 13, 2025 · 04fb4db · 04fb4db
1 parent e1d73a0
commit 04fb4db
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Showing 3 changed files with 14 additions and 4 deletions.
diff --git a/pw_log_null/BUILD.gn b/pw_log_null/BUILD.gn
@@ -31,7 +31,10 @@ pw_source_set("pw_log_null") {
   public = [ "public_overrides/pw_log_backend/log_backend.h" ]
   sources = [ "public/pw_log_null/log_null.h" ]
   friend = [ ":*" ]
-  public_deps = [ dir_pw_preprocessor ]
+  public_deps = [
+    "$dir_pw_log:pw_log.facade",
+    dir_pw_preprocessor,
+  ]
 }
 
 pw_source_set("pw_log_null.impl") {

diff --git a/pw_log_null/CMakeLists.txt b/pw_log_null/CMakeLists.txt
@@ -23,6 +23,7 @@ pw_add_library(pw_log_null INTERFACE
     public_overrides
   PUBLIC_DEPS
     pw_preprocessor
+    pw_log.facade
 )
 
 pw_add_test(pw_log_null.test

diff --git a/pw_log_null/public/pw_log_null/log_null.h b/pw_log_null/public/pw_log_null/log_null.h
@@ -13,7 +13,7 @@
 // the License.
 #pragma once
 
-#include "pw_preprocessor/arguments.h"
+#include "pw_log/levels.h"
 #include "pw_preprocessor/compiler.h"
 #include "pw_preprocessor/util.h"
 
@@ -49,5 +49,11 @@ static inline void pw_log_Ignored(int level,
 
 PW_EXTERN_C_END
 
-#define PW_HANDLE_LOG(level, module, flags, message, ...) \
-  pw_log_Ignored((level), module, (flags), message PW_COMMA_ARGS(__VA_ARGS__))
+#define PW_HANDLE_LOG(level, module, flags, ...)                           \
+  do {                                                                     \
+    static_assert(                                                         \
+        (level) != PW_LOG_LEVEL_FATAL,                                     \
+        "pw_log_null does not support FATAL logs, including asserts from " \
+        "pw_assert_log; disabling FATAL logs or asserts is unsafe");       \
+    pw_log_Ignored((level), (module), (flags), __VA_ARGS__);               \
+  } while (0)