Address Copilot review comments

- foreach_mapping: remove const (Trie only has const_iterator, so
  const_cast is still needed but function is now semantically correct)
- Cache.cc: document default_volumes_host_rec as intentional singleton
- CacheHosting.cc: restore tmp++ (tmp=line_end broke multi-param lines),
  remove unreachable null check after new, use char array for "volume"
  literal instead of const_cast
- ReverseProxy.cc: add acquire()/release() around rewrite_table access
  in init_remap_volume_host_records, document startup-only constraint
- Test files: remove trailing commas from ATSReplayTest calls

Author: zwoop

include/proxy/http/remap/UrlMappingPathIndex.h

@@ -40,12 +40,13 @@ class UrlMappingPathIndex
   void         Print() const;
   std::string  PrintUrlMappingPathIndex() const;
 
-  // Apply a function to each url_mapping in this index
+  // Apply a function to each url_mapping in this index.
+  // Note: Trie only exposes const_iterator, so const_cast is required.
   template <typename Func>
   void
-  foreach_mapping(Func &&f) const
+  foreach_mapping(Func &&f)
   {
-    for (const auto &trie_pair : m_tries) {
+    for (auto &trie_pair : m_tries) {
       for (auto const &mapping : *trie_pair.second) {
         f(const_cast<url_mapping &>(mapping));
       }

src/iocore/cache/Cache.cc

@@ -100,7 +100,8 @@ ClassAllocator<EvacuationBlock, false>    evacuationBlockAllocator("evacuationBl
 ClassAllocator<CacheRemoveCont, false>    cacheRemoveContAllocator("cacheRemoveCont");
 ClassAllocator<EvacuationKey, false>      evacuationKeyAllocator("evacuationKey");
 std::unordered_set<std::string>           known_bad_disks;
-CacheHostRecord                          *default_volumes_host_rec = nullptr;
+// Process-lifetime singleton: allocated during cache init and intentionally never freed.
+CacheHostRecord *default_volumes_host_rec = nullptr;
 
 namespace
 {

src/iocore/cache/CacheHosting.cc

@@ -819,7 +819,7 @@ ConfigVolumes::BuildListFromString(char *config_file_path, char *file_buf)
 
       // ends here
       if (end < line_end) {
-        tmp = line_end;
+        tmp++;
       }
     }
 
@@ -881,16 +881,12 @@ createCacheHostRecord(const char *volume_str, char *errbuf, size_t errbufsize)
 
   CacheHostRecord *host_rec = new CacheHostRecord();
 
-  if (!host_rec) {
-    snprintf(errbuf, errbufsize, "Memory allocation failed");
-    return nullptr;
-  }
-
   // Build a minimal matcher_line structure with just the volume= directive
+  char         volume_key[] = "volume";
   matcher_line ml;
   memset(&ml, 0, sizeof(ml));
 
-  ml.line[0][0] = const_cast<char *>("volume");
+  ml.line[0][0] = volume_key;
   ml.line[1][0] = const_cast<char *>(volume_str);
   ml.num_el     = 1;
   ml.dest_entry = -1;

src/proxy/ReverseProxy.cc

@@ -203,7 +203,8 @@ init_store_volume_host_records(UrlRewrite::MappingsStore &store)
   }
 }
 
-// This is called after the cache is initialized, since we may need the volume_host_records
+// This is called after the cache is initialized, since we may need the volume_host_records.
+// Must only be called during startup before any remap reload can occur.
 void
 init_remap_volume_host_records()
 {
@@ -213,6 +214,8 @@ init_remap_volume_host_records()
     return;
   }
 
+  table->acquire();
+
   Dbg(dbg_ctl_url_rewrite, "Initializing volume_host_rec for all remap rules after cache init");
 
   // Initialize for all mapping stores
@@ -221,6 +224,8 @@ init_remap_volume_host_records()
   init_store_volume_host_records(table->permanent_redirects);
   init_store_volume_host_records(table->temporary_redirects);
   init_store_volume_host_records(table->forward_mappings_with_recv_port);
+
+  table->release();
 }
 
 int

tests/gold_tests/cache/cache_volume_defaults.test.py

@@ -21,4 +21,4 @@
 - Verify that hosting.config takes priority over default_volumes
 '''
 
-Test.ATSReplayTest(replay_file="cache_volume_defaults.replay.yaml",)
+Test.ATSReplayTest(replay_file="cache_volume_defaults.replay.yaml")

tests/gold_tests/cache/cache_volume_features.test.py

@@ -21,4 +21,4 @@
 - Integration between both features
 '''
 
-Test.ATSReplayTest(replay_file="cache_volume_features.replay.yaml",)
+Test.ATSReplayTest(replay_file="cache_volume_features.replay.yaml")