Ignore banlist.dat

This also allows to remove the "dirty" argument, which can now be
deduced from the return value of Read().

src/addrdb.cpp

@@ -197,16 +197,15 @@ bool CBanDB::Write(const banmap_t& banSet)
     return false;
 }
 
-bool CBanDB::Read(banmap_t& banSet, bool& dirty)
+bool CBanDB::Read(banmap_t& banSet)
 {
-    // If the JSON banlist does not exist, then try to read the non-upgraded banlist.dat.
-    if (!fs::exists(m_banlist_json)) {
-        // If this succeeds then we need to flush to disk in order to create the JSON banlist.
-        dirty = true;
-        return DeserializeFileDB(m_banlist_dat, banSet, CLIENT_VERSION);
+    if (fs::exists(m_banlist_dat)) {
+        LogPrintf("banlist.dat ignored because it can only be read by " PACKAGE_NAME " version 22.x. Remove %s to silence this warning.\n", m_banlist_dat);
+    }
+    // If the JSON banlist does not exist, then recreate it
+    if (!fs::exists(m_banlist_json)) {
+        return false;
     }
-
-    dirty = false;
 
     std::map<std::string, util::SettingsValue> settings;
     std::vector<std::string> errors;

src/addrdb.h

@@ -76,7 +76,7 @@ public:
     static bool Read(CAddrMan& addr, CDataStream& ssPeers);
 };
 
-/** Access to the banlist databases (banlist.json and banlist.dat) */
+/** Access to the banlist database (banlist.json) */
 class CBanDB
 {
 private:
@@ -95,11 +95,9 @@ public:
      * Read the banlist from disk.
      * @param[out] banSet The loaded list. Set if `true` is returned, otherwise it is left
      * in an undefined state.
-     * @param[out] dirty Indicates whether the loaded list needs flushing to disk. Set if
-     * `true` is returned, otherwise it is left in an undefined state.
      * @return true on success
      */
-    bool Read(banmap_t& banSet, bool& dirty);
+    bool Read(banmap_t& banSet);
 };
 
 /**

src/banman.cpp

@@ -18,7 +18,7 @@ BanMan::BanMan(fs::path ban_file, CClientUIInterface* client_interface, int64_t
     if (m_client_interface) m_client_interface->InitMessage(_("Loading banlist…").translated);
 
     int64_t n_start = GetTimeMillis();
-    if (m_ban_db.Read(m_banned, m_is_dirty)) {
+    if (m_ban_db.Read(m_banned)) {
         SweepBanned(); // sweep out unused entries
 
         LogPrint(BCLog::NET, "Loaded %d banned node addresses/subnets  %dms\n", m_banned.size(),

src/banman.h

@@ -88,7 +88,7 @@ private:
 
     RecursiveMutex m_cs_banned;
     banmap_t m_banned GUARDED_BY(m_cs_banned);
-    bool m_is_dirty GUARDED_BY(m_cs_banned);
+    bool m_is_dirty GUARDED_BY(m_cs_banned){false};
     CClientUIInterface* m_client_interface = nullptr;
     CBanDB m_ban_db;
     const int64_t m_default_ban_time;

src/test/fuzz/banman.cpp

@@ -52,8 +52,7 @@ FUZZ_TARGET_INIT(banman, initialize_banman)
     const bool start_with_corrupted_banlist{fuzzed_data_provider.ConsumeBool()};
     bool force_read_and_write_to_err{false};
     if (start_with_corrupted_banlist) {
-        const std::string sfx{fuzzed_data_provider.ConsumeBool() ? ".dat" : ".json"};
-        assert(WriteBinaryFile(banlist_file.string() + sfx,
+        assert(WriteBinaryFile(banlist_file.string() + ".json",
                                fuzzed_data_provider.ConsumeRandomLengthString()));
     } else {
         force_read_and_write_to_err = fuzzed_data_provider.ConsumeBool();
@@ -114,6 +113,5 @@ FUZZ_TARGET_INIT(banman, initialize_banman)
             (void)(banmap == banmap_read);
         }
     }
-    fs::remove(banlist_file.string() + ".dat");
     fs::remove(banlist_file.string() + ".json");
 }