Avoid repeated channel alias parsing in constrained companions

examples/companion_radio/MyMesh.cpp

@@ -1785,7 +1785,7 @@ bool MyMesh::resolveChannelAlias(ChannelDetails& channel) const {
       })) return false;
   const auto kind = parseCompanionChannelAlias(channel.name).kind;
 #if MESH_ENABLE_MESHTEXT_CHAT
-  if (isMeshtextChannel(channel)) channel.channel.tx_radio = mesh::RADIO_TX_OFF;
+  if (kind == CompanionChannelKind::Meshtext) channel.channel.tx_radio = mesh::RADIO_TX_OFF;
 #endif
   if (isAliasRadio2Defined()
       && (kind == CompanionChannelKind::Radio2 || kind == CompanionChannelKind::Meshtext)) {

scripts/nrf52_flash_trim.py

@@ -259,7 +259,7 @@ def compile_packed_help(build_env, node):
     return build_env.Object(node, **flags)
 
 
-def _compile_shared_reply_copies(build_env, node, relative_path):
+def _compile_shared_reply_copies(build_env, node, relative_path, extra_flags=()):
     source = Path(node.srcnode().get_abspath()).resolve()
     expected = Path(build_env.subst("$PROJECT_DIR/" + relative_path)).resolve()
     if source != expected:
@@ -267,8 +267,9 @@ def _compile_shared_reply_copies(build_env, node, relative_path):
     # GCC otherwise expands many constant strcpy replies into repeated stores.
     # Use the same libc function and strings, with no parser or output changes.
     flags = list(build_env.get("CCFLAGS", ()))
-    if "-fno-builtin-strcpy" not in flags:
-        flags.append("-fno-builtin-strcpy")
+    for flag in ("-fno-builtin-strcpy", *extra_flags):
+        if flag not in flags:
+            flags.append(flag)
     return build_env.Object(node, CCFLAGS=flags)
 
 
@@ -278,7 +279,8 @@ def compile_shared_cli_replies(build_env, node):
 
 
 def compile_shared_companion_replies(build_env, node):
-    return _compile_shared_reply_copies(build_env, node, "examples/companion_radio/MyMesh.cpp")
+    return _compile_shared_reply_copies(build_env, node, "examples/companion_radio/MyMesh.cpp",
+                                       ("-fno-builtin-strncpy",))
 
 
 def companion_shared_replies_policy(platform, mcu, env_name, src_filter,

src/helpers/CompanionChannelAlias.h

@@ -34,9 +34,12 @@ inline CompanionChannelAlias parseCompanionChannelAlias(const char* name) {
 // Only exact named radio2 aliases request RF setup. Ordinary channels and
 // arbitrary r2 labels keep the operator's existing profile.
 inline const char* companionChannelRadio2Preset(const char* name) {
-  const auto alias = parseCompanionChannelAlias(name);
-  return alias.kind == CompanionChannelKind::Radio2
-      && mesh::cli::radio2PresetTuple(alias.tail) ? alias.tail : nullptr;
+  if (!name) return nullptr;
+  if (*name == '#') ++name;
+  if (strncmp(name, "r2-", 3)) return nullptr;
+  name += 3;
+  // An exact preset tail also excludes every invalid/nested alias form.
+  return mesh::cli::radio2PresetTuple(name) ? name : nullptr;
 }
 
 inline bool companionChannelCanonicalName(const char* name, char* out, size_t size) {

test/test_companion_channel_alias.py

@@ -94,6 +94,16 @@ static void grammar() {
     assert(!companionChannelRadio2Preset(name));
   }
   assert(!companionChannelRadio2Preset(nullptr));
+  for (const char* prefix : {"", "#", "r2-", "#r2-", "mt-", "#mt-", "r2-r2-", "#r2-mt-"}) {
+    for (const char* tail : {"", "r", "r2", "#", "mediamesh", "mediamesh-range",
+                             "MediaMesh", "mediamesh-extra", "mediamesh,32"}) {
+      char name[64]; snprintf(name, sizeof(name), "%s%s", prefix, tail);
+      const auto alias = parseCompanionChannelAlias(name);
+      const char* expected = alias.kind == CompanionChannelKind::Radio2
+          && mesh::cli::radio2PresetTuple(alias.tail) ? alias.tail : nullptr;
+      assert(companionChannelRadio2Preset(name) == expected);
+    }
+  }
   puts("PASS grammar");
 }
 static void canonical() {

test/test_nrf52_flash_trim.py

@@ -127,7 +127,8 @@ class Nrf52FlashTrimTest(unittest.TestCase):
         companion = Node(ROOT / "examples/companion_radio/MyMesh.cpp")
         result, flags = TRIM.compile_shared_companion_replies(env, companion)
         self.assertIs(result, companion)
-        self.assertEqual(flags["CCFLAGS"], ["-Os", "-flto", "-fno-builtin-strcpy"])
+        self.assertEqual(flags["CCFLAGS"], ["-Os", "-flto", "-fno-builtin-strcpy",
+                                          "-fno-builtin-strncpy"])
         self.assertEqual(env["CCFLAGS"], ["-Os", "-flto"])
         for path in ("examples/simple_repeater/MyMesh.cpp", "test/fixtures/MyMesh.cpp",
                      "src/helpers/CommonCLI.cpp", "src/helpers/RadioProfileCLI.cpp"):