merge bitcoin#23104: Avoid breaking single log lines over multiple lines in the log file

Author: kwvg

src/sync.cpp

@@ -94,34 +94,36 @@ LockData& GetLockData() {
 
 static void potential_deadlock_detected(const LockPair& mismatch, const LockStack& s1, const LockStack& s2)
 {
-    std::string strOutput = "";
-    strOutput += "POTENTIAL DEADLOCK DETECTED\n";
-    strOutput += "Previous lock order was:\n";
+    std::string log_message{};
+    log_message += "POTENTIAL DEADLOCK DETECTED\n";
+    log_message += "Previous lock order was:\n";
     for (const LockStackItem& i : s1) {
+        std::string prefix{};
         if (i.first == mismatch.first) {
-            strOutput += " (1)";
+            prefix = " (1)";
         }
         if (i.first == mismatch.second) {
-            strOutput += " (2)";
+            prefix = " (2)";
         }
-        strOutput += strprintf(" %s\n", i.second.ToString());
+        log_message += strprintf("%s %s\n", prefix, i.second.ToString());
     }
 
     std::string mutex_a, mutex_b;
-    strOutput += "Current lock order is:\n";
+    log_message += "Current lock order is:\n";
     for (const LockStackItem& i : s2) {
+        std::string prefix{};
         if (i.first == mismatch.first) {
-            strOutput += " (1)";
+            prefix = " (1)";
             mutex_a = i.second.Name();
         }
         if (i.first == mismatch.second) {
-            strOutput += " (2)";
+            prefix = " (2)";
             mutex_b = i.second.Name();
         }
-        strOutput += strprintf(" %s\n", i.second.ToString());
+        log_message += strprintf("%s %s\n", prefix, i.second.ToString());
     }
 
-    LogPrintf("%s\n", strOutput);
+    LogPrintf("%s\n", log_message);
 
     if (g_debug_lockorder_abort) {
         tfm::format(std::cerr, "Assertion failed: detected inconsistent lock order for %s, details in debug log.\n", s2.back().second.ToString());

src/wallet/coinselection.cpp

@@ -340,15 +340,15 @@ bool KnapsackSolver(const CAmount& nTargetValue, std::vector<OutputGroup>& group
         util::insert(setCoinsRet, lowest_larger->m_outputs);
         nValueRet += lowest_larger->m_value;
     } else {
-        std::string s = "CWallet::SelectCoinsMinConf best subset: ";
+        std::string log_message{"Coin selection best subset: "};
         for (unsigned int i = 0; i < applicable_groups.size(); i++) {
             if (vfBest[i]) {
                 util::insert(setCoinsRet, applicable_groups[i].m_outputs);
                 nValueRet += applicable_groups[i].m_value;
-                s += FormatMoney(applicable_groups[i].m_value) + " ";
+                log_message += strprintf("%s ", FormatMoney(applicable_groups[i].m_value));
             }
         }
-        LogPrint(BCLog::SELECTCOINS, "%s - total %s\n", s, FormatMoney(nBest));
+        LogPrint(BCLog::SELECTCOINS, "%stotal %s\n", log_message, FormatMoney(nBest));
     }
 
     // There is no change in PS, so we know the fee beforehand,