ci: drop <config.h> include + collapse radix descent duplicate

* test/unit/http_request_operator_stream_test.cpp: remove the
  `#include <config.h>` I added in 203780f.  HAVE_BAUTH is forwarded
  into test compiles via -DHAVE_BAUTH on the libtool command line
  (the same mechanism every other HAVE_BAUTH-gated test uses);
  pulling in config.h directly re-defines DEBUG and conflicts with
  the -DDEBUG flag autotools sets on the debug + coverage / sanitiser
  lanes (DEBUG macro redefined -Werror). The `#ifdef HAVE_BAUTH` gate
  itself stays; only the redundant include goes.

* src/httpserver/detail/radix_tree.hpp: hoist the
  has_terminus_at / remove descent loop into a single templated
  walk_registered_pattern_ helper.  The two functions both walked
  the registered-pattern tree by exact-child-then-wildcard step and
  shared a 14-line / 101-token block (PMD CPD finding).  The helper
  is templated on Node so the mutable / const variants share one
  descent body; CCN stays inside the gate and the duplicate is gone.

Author: etr

src/httpserver/detail/radix_tree.hpp

@@ -271,20 +271,9 @@ class radix_tree {
     // prefix terminus is already registered at /admin (and vice versa)
     // — silent shadowing would corrupt the (method, path) cache key.
     bool has_terminus_at(const std::string& path, bool is_prefix) const {
-        const radix_node<T>* node = root_.get();
-        const auto segments = tokenize(path);
-        for (const std::string& seg : segments) {
-            auto it = node->children_.find(seg);
-            if (it != node->children_.end()) {
-                node = it->second.get();
-                continue;
-            }
-            if (node->wildcard_child_ && is_wildcard_segment(seg)) {
-                node = node->wildcard_child_.get();
-                continue;
-            }
-            return false;
-        }
+        const radix_node<T>* node = walk_registered_pattern_(root_.get(),
+                                                             tokenize(path));
+        if (node == nullptr) return false;
         return is_prefix ? node->prefix_terminus_.has_value()
                          : node->exact_terminus_.has_value();
     }
@@ -295,23 +284,9 @@ class radix_tree {
     // segment value (e.g. "42"), remove() receives the registered pattern
     // (e.g. "{id}") and matches wildcard nodes by the placeholder shape.
     bool remove(const std::string& path, bool is_prefix) {
-        radix_node<T>* node = root_.get();
-        const auto segments = tokenize(path);
-        for (const std::string& seg : segments) {
-            auto it = node->children_.find(seg);
-            if (it != node->children_.end()) {
-                node = it->second.get();
-                continue;
-            }
-            // Walk wildcard child if seg matches the {name} placeholder
-            // shape. We compare the exact registered key, so removal of
-            // /users/{id} requires the same {id} string.
-            if (node->wildcard_child_ && is_wildcard_segment(seg)) {
-                node = node->wildcard_child_.get();
-                continue;
-            }
-            return false;
-        }
+        radix_node<T>* node = walk_registered_pattern_(root_.get(),
+                                                       tokenize(path));
+        if (node == nullptr) return false;
         if (is_prefix) {
             if (!node->prefix_terminus_.has_value()) return false;
             node->prefix_terminus_.reset();
@@ -337,6 +312,34 @@ class radix_tree {
         return ::httpserver::http::http_utils::tokenize_url(path);
     }
 
+    // Descend from `start` along `segments`, matching exact children
+    // first and falling back to a wildcard child when the segment has
+    // the {name} placeholder shape. Returns the terminal node or
+    // nullptr if any segment failed to match.
+    //
+    // Templated on Node (radix_node<T> or const radix_node<T>) so the
+    // const-correct mutable / const variants share one descent body --
+    // collapses the previous in-place duplicate descent loops in
+    // has_terminus_at and remove (PMD CPD finding).
+    template <class Node>
+    static Node* walk_registered_pattern_(Node* start,
+            const std::vector<std::string>& segments) {
+        Node* node = start;
+        for (const std::string& seg : segments) {
+            auto it = node->children_.find(seg);
+            if (it != node->children_.end()) {
+                node = it->second.get();
+                continue;
+            }
+            if (node->wildcard_child_ && is_wildcard_segment(seg)) {
+                node = node->wildcard_child_.get();
+                continue;
+            }
+            return nullptr;
+        }
+        return node;
+    }
+
     static bool is_wildcard_segment(const std::string& seg) noexcept {
         return seg.size() >= 2 && seg.front() == '{' && seg.back() == '}';
     }

test/unit/http_request_operator_stream_test.cpp

@@ -26,15 +26,16 @@
 // through create_test_request::expose_credentials_in_logs() for unit
 // scope) restores the v1 verbose form for development.
 
-// HAVE_BAUTH (config.h via HAVE_CONFIG_H) gates the username / password
-// surfaces that operator<< streams. On HAVE_BAUTH-off builds (Windows
-// MSYS2 lane, flag-invariance-off lane) get_user() / get_pass() return
-// empty string_views by contract, so the user:"admin" / pass:"hunter2"
-// expectations below do not hold; the BAUTH-off build path is covered
-// by webserver_dauth_unavailable / webserver_features tests instead.
-#if defined(HAVE_CONFIG_H)
-#include <config.h>
-#endif
+// HAVE_BAUTH gates the username / password surfaces that operator<<
+// streams. On HAVE_BAUTH-off builds (Windows MSYS2 lane, flag-invariance-
+// off lane) get_user() / get_pass() return empty string_views by
+// contract, so the user:"admin" / pass:"hunter2" expectations below do
+// not hold; the BAUTH-off build path is covered by
+// webserver_dauth_unavailable / webserver_features tests instead.
+// HAVE_BAUTH is forwarded into the test compile via -DHAVE_BAUTH on the
+// libtool command line; no explicit <config.h> include is needed (and
+// would clash with the -DDEBUG flag autotools sets on debug lanes,
+// since config.h re-defines DEBUG).
 
 #include <sstream>
 #include <string>