introduce and use the generalized node::Warnings interface

Instead of having separate warning functions (and globals) for each
different warning that can be raised, encapsulate this logic into
a single class and allow to (un)set any number of warnings.

Introduces behaviour change:
- the `-alertnotify` command is executed for all
  `KernelNotifications::warningSet` calls, which now also covers the
  `LARGE_WORK_INVALID_CHAIN` warning.
- previously, warnings were returned based on a predetermined order,
  e.g. with the "pre-release test build" warning always first. This
  is no longer the case, and Warnings::GetMessages() will return
  messages sorted by the id of the warning.

Removes warnings.cpp from kernel.

Author: stickies-v

doc/release-notes-30058.md

@@ -0,0 +1,7 @@
+- When running with -alertnotify, an alert can now be raised multiple
+times instead of just once. Previously, it was only raised when unknown
+new consensus rules were activated, whereas the scope has now been
+increased to include all kernel warnings. Specifically, alerts will now
+also be raised when an invalid chain with a large amount of work has
+been detected. Additional warnings may be added in the future.
+(#30058)

src/Makefile.am

@@ -196,6 +196,7 @@ BITCOIN_CORE_H = \
   kernel/messagestartchars.h \
   kernel/notifications_interface.h \
   kernel/validation_cache_sizes.h \
+  kernel/warning.h \
   key.h \
   key_io.h \
   logging.h \
@@ -996,8 +997,7 @@ libbitcoinkernel_la_SOURCES = \
   util/tokenpipe.cpp \
   validation.cpp \
   validationinterface.cpp \
-  versionbits.cpp \
-  warnings.cpp
+  versionbits.cpp
 
 # Required for obj/build.h to be generated first.
 # More details: https://www.gnu.org/software/automake/manual/html_node/Built-Sources-Example.html

src/Makefile.test.include

@@ -118,6 +118,7 @@ BITCOIN_TESTS =\
   test/net_peer_eviction_tests.cpp \
   test/net_tests.cpp \
   test/netbase_tests.cpp \
+  test/node_warnings_tests.cpp \
   test/orphanage_tests.cpp \
   test/peerman_tests.cpp \
   test/pmt_tests.cpp \

src/bitcoin-chainstate.cpp

@@ -16,6 +16,7 @@
 #include <kernel/checks.h>
 #include <kernel/context.h>
 #include <kernel/validation_cache_sizes.h>
+#include <kernel/warning.h>
 
 #include <consensus/validation.h>
 #include <core_io.h>
@@ -28,6 +29,7 @@
 #include <util/fs.h>
 #include <util/signalinterrupt.h>
 #include <util/task_runner.h>
+#include <util/translation.h>
 #include <validation.h>
 #include <validationinterface.h>
 
@@ -86,9 +88,13 @@ int main(int argc, char* argv[])
         {
             std::cout << "Progress: " << title.original << ", " << progress_percent << ", " << resume_possible << std::endl;
         }
-        void warning(const bilingual_str& warning) override
+        void warningSet(kernel::Warning id, const bilingual_str& message) override
         {
-            std::cout << "Warning: " << warning.original << std::endl;
+            std::cout << "Warning " << static_cast<int>(id) << " set: " << message.original << std::endl;
+        }
+        void warningUnset(kernel::Warning id) override
+        {
+            std::cout << "Warning " << static_cast<int>(id) << " unset" << std::endl;
         }
         void flushError(const bilingual_str& message) override
         {

src/kernel/notifications_interface.h

@@ -16,6 +16,8 @@ namespace kernel {
 
 //! Result type for use with std::variant to indicate that an operation should be interrupted.
 struct Interrupted{};
+enum class Warning;
+
 
 //! Simple result type for functions that need to propagate an interrupt status and don't have other return values.
 using InterruptResult = std::variant<std::monostate, Interrupted>;
@@ -38,7 +40,8 @@ class Notifications
     [[nodiscard]] virtual InterruptResult blockTip(SynchronizationState state, CBlockIndex& index) { return {}; }
     virtual void headerTip(SynchronizationState state, int64_t height, int64_t timestamp, bool presync) {}
     virtual void progress(const bilingual_str& title, int progress_percent, bool resume_possible) {}
-    virtual void warning(const bilingual_str& warning) {}
+    virtual void warningSet(Warning id, const bilingual_str& message) {}
+    virtual void warningUnset(Warning id) {}
 
     //! The flush error notification is sent to notify the user that an error
     //! occurred while flushing block data to disk. Kernel code may ignore flush

src/kernel/warning.h

@@ -0,0 +1,14 @@
+// Copyright (c) 2024-present The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#ifndef BITCOIN_KERNEL_WARNING_H
+#define BITCOIN_KERNEL_WARNING_H
+
+namespace kernel {
+enum class Warning {
+    UNKNOWN_NEW_RULES_ACTIVATED,
+    LARGE_WORK_INVALID_CHAIN,
+};
+} // namespace kernel
+#endif // BITCOIN_KERNEL_WARNING_H

src/node/abort.cpp

@@ -12,13 +12,12 @@
 
 #include <atomic>
 #include <cstdlib>
-#include <string>
 
 namespace node {
 
 void AbortNode(util::SignalInterrupt* shutdown, std::atomic<int>& exit_status, const bilingual_str& message)
 {
-    SetMiscWarning(message);
+    g_warnings.Set(Warning::FATAL_INTERNAL_ERROR, message);
     InitError(_("A fatal internal error occurred, see debug.log for details: ") + message);
     exit_status.store(EXIT_FAILURE);
     if (shutdown && !(*shutdown)()) {

src/node/interfaces.cpp

@@ -93,7 +93,7 @@ class NodeImpl : public Node
     explicit NodeImpl(NodeContext& context) { setContext(&context); }
     void initLogging() override { InitLogging(args()); }
     void initParameterInteraction() override { InitParameterInteraction(args()); }
-    bilingual_str getWarnings() override { return Join(GetWarnings(), Untranslated("<hr />")); }
+    bilingual_str getWarnings() override { return Join(node::g_warnings.GetMessages(), Untranslated("<hr />")); }
     int getExitStatus() override { return Assert(m_context)->exit_status.load(); }
     uint32_t getLogCategories() override { return LogInstance().GetCategoryMask(); }
     bool baseInitialize() override

src/node/kernel_notifications.cpp

@@ -10,6 +10,7 @@
 #include <common/args.h>
 #include <common/system.h>
 #include <kernel/context.h>
+#include <kernel/warning.h>
 #include <logging.h>
 #include <node/abort.h>
 #include <node/interface_ui.h>
@@ -46,16 +47,6 @@ static void AlertNotify(const std::string& strMessage)
 #endif
 }
 
-static void DoWarning(const bilingual_str& warning)
-{
-    static bool fWarned = false;
-    node::SetMiscWarning(warning);
-    if (!fWarned) {
-        AlertNotify(warning.original);
-        fWarned = true;
-    }
-}
-
 namespace node {
 
 kernel::InterruptResult KernelNotifications::blockTip(SynchronizationState state, CBlockIndex& index)
@@ -80,9 +71,16 @@ void KernelNotifications::progress(const bilingual_str& title, int progress_perc
     uiInterface.ShowProgress(title.translated, progress_percent, resume_possible);
 }
 
-void KernelNotifications::warning(const bilingual_str& warning)
+void KernelNotifications::warningSet(kernel::Warning id, const bilingual_str& message)
+{
+    if (node::g_warnings.Set(id, message)) {
+        AlertNotify(message.original);
+    }
+}
+
+void KernelNotifications::warningUnset(kernel::Warning id)
 {
-    DoWarning(warning);
+    g_warnings.Unset(id);
 }
 
 void KernelNotifications::flushError(const bilingual_str& message)

src/node/kernel_notifications.h

@@ -15,6 +15,10 @@ class CBlockIndex;
 enum class SynchronizationState;
 struct bilingual_str;
 
+namespace kernel {
+enum class Warning;
+} // namespace kernel
+
 namespace util {
 class SignalInterrupt;
 } // namespace util
@@ -34,7 +38,9 @@ class KernelNotifications : public kernel::Notifications
 
     void progress(const bilingual_str& title, int progress_percent, bool resume_possible) override;
 
-    void warning(const bilingual_str& warning) override;
+    void warningSet(kernel::Warning id, const bilingual_str& message) override;
+
+    void warningUnset(kernel::Warning id) override;
 
     void flushError(const bilingual_str& message) override;