regex_remap plugin fix for no specified strategy (#12599)

Author: traeak

plugins/regex_remap/regex_remap.cc

@@ -226,6 +226,11 @@ class RemapRegex
   {
     return _lowercase_substitutions;
   }
+  inline bool
+  has_strategy() const
+  {
+    return _has_strategy;
+  }
   inline std::string const &
   strategy() const
   {
@@ -268,7 +273,8 @@ class RemapRegex
   int _connect_timeout     = -1;
   int _dns_timeout         = -1;
 
-  std::string _strategy = {};
+  bool        _has_strategy = false;
+  std::string _strategy     = {};
 
   Override *_first_override = nullptr;
   int       _sub_pos[MAX_SUBS];
@@ -317,7 +323,8 @@ RemapRegex::initialize(const std::string &reg, const std::string &sub, const std
     } else if (opt.compare(start, 23, "lowercase_substitutions") == 0) {
       _lowercase_substitutions = true;
     } else if (opt.compare(start, 8, "strategy") == 0) {
-      _strategy = opt_val;
+      _has_strategy = true;
+      _strategy     = opt_val;
     } else if (opt_val.size() <= 0) {
       // All other options have a required value
       TSError("[%s] Malformed options: %s", PLUGIN_NAME, opt.c_str());
@@ -980,17 +987,19 @@ TSRemapDoRemap(void *ih, TSHttpTxn txnp, TSRemapRequestInfo *rri)
         Dbg(dbg_ctl, "Setting DNS timeout to %d", re->dns_timeout_option());
         TSHttpTxnDNSTimeoutSet(txnp, re->dns_timeout_option());
       }
-      auto const &strat = re->strategy();
-      if (strat.empty() || "null" == strat) {
-        Dbg(dbg_ctl, "Clearing strategy (use parent.config)");
-        TSHttpTxnNextHopStrategySet(txnp, nullptr);
-      } else {
-        void const *const stratptr = TSHttpTxnNextHopNamedStrategyGet(txnp, strat.c_str());
-        if (nullptr == stratptr) {
-          Dbg(dbg_ctl, "No strategy found with name '%s'", strat.c_str());
+      if (re->has_strategy()) {
+        auto const &strat = re->strategy();
+        if (strat.empty() || "null" == strat) {
+          Dbg(dbg_ctl, "Clearing strategy (use parent.config)");
+          TSHttpTxnNextHopStrategySet(txnp, nullptr);
         } else {
-          Dbg(dbg_ctl, "Setting strategy to %s", strat.c_str());
-          TSHttpTxnNextHopStrategySet(txnp, stratptr);
+          void const *const stratptr = TSHttpTxnNextHopNamedStrategyGet(txnp, strat.c_str());
+          if (nullptr == stratptr) {
+            Dbg(dbg_ctl, "No strategy found with name '%s'", strat.c_str());
+          } else {
+            Dbg(dbg_ctl, "Setting strategy to %s", strat.c_str());
+            TSHttpTxnNextHopStrategySet(txnp, stratptr);
+          }
         }
       }
       bool lowercase_substitutions = false;