Fix loading of DDFs due constants.json race (#7793)

Stupid beginner mistake. The JSON files are read in arbitrary file system order. Which is ok except for the constants.json which need to be read first in order to determine if a DDF should be loaded.

device_descriptions.cpp

@@ -1083,13 +1083,14 @@ const DeviceDescription &DeviceDescriptions::get(const Resource *resource, DDF_M
 
     if (modelidAtomIndex == 0 || mfnameAtomIndex == 0)
     {
-        return d->invalidDescription; // should not happen
+        U_ASSERT(modelidItem->toString().isEmpty());
+        U_ASSERT(mfnameItem->toString().isEmpty());
+        return d->invalidDescription; // happens when called from legacy init code addLightNode() etc.
     }
 
     U_ASSERT(modelidAtomIndex != 0);
     U_ASSERT(mfnameAtomIndex != 0);
 
-
     /*
      * Filter matching DDFs, there can be multiple entries for the same modelid and manufacturer name.
      * Further sorting for the 'best' match according to attr/ddf_policy is done afterwards.
@@ -1172,7 +1173,14 @@ const DeviceDescription &DeviceDescriptions::get(const Resource *resource, DDF_M
 
             if (ddf1.storageLocation == deCONZ::DdfLocation || ddf1.storageLocation == deCONZ::DdfUserLocation)
             {
-                rawJsonIndex = matchedIndices[i];
+                if (rawJsonIndex == invalidIndex)
+                {
+                    rawJsonIndex = matchedIndices[i];
+                }
+                else if (d->descriptions[rawJsonIndex].status == QLatin1String("Draft"))
+                {
+                    rawJsonIndex = matchedIndices[i];
+                }
                 continue;
             }
 
@@ -1997,6 +2005,35 @@ void DeviceDescriptions::readAllRawJson()
 
     std::array<deCONZ::StorageLocation, 2> locations = { deCONZ::DdfLocation, deCONZ::DdfUserLocation};
 
+    bool hasConstants = false;
+
+    // need to resolve constants first
+    for (size_t dit = 0; dit < locations.size(); dit++)
+    {
+        const QString filePath = deCONZ::getStorageLocation(locations[dit]) + "/generic/constants.json";
+
+        pctx->filePath[0] = '\0';
+        pctx->filePathLength = 0;
+        pctx->scratchPos = 0;
+
+        {
+            U_SStream ss;
+            U_sstream_init(&ss, pctx->filePath, sizeof(pctx->filePath));
+            U_sstream_put_str(&ss, filePath.toUtf8().data());
+            pctx->filePathLength = ss.pos;
+        }
+
+        if (DDF_ReadFileInMemory(pctx))
+        {
+            if (DDF_ReadConstantsJson(pctx, d->constants2))
+            {
+                hasConstants = true;
+            }
+        }
+    }
+
+    U_ASSERT(hasConstants);
+
     for (size_t dit = 0; dit < locations.size(); dit++)
     {
         const QString dirpath = deCONZ::getStorageLocation(locations[dit]);
@@ -2019,13 +2056,6 @@ void DeviceDescriptions::readAllRawJson()
 
             if (it.filePath().endsWith(QLatin1String("generic/constants.json")))
             {
-                if (DDF_ReadFileInMemory(pctx))
-                {
-                    if (DDF_ReadConstantsJson(pctx, d->constants2))
-                    {
-
-                    }
-                }
             }
             else if (it.fileName() == QLatin1String("button_maps.json"))
             {  }
@@ -2836,7 +2866,7 @@ void DeviceDescriptions::handleDDFInitRequest(const Event &event)
 
         if (result >= 0)
         {
-            DBG_Printf(DBG_INFO, "DEV found DDF for " FMT_MAC ", path: %s\n", FMT_MAC_CAST(event.deviceKey()), qPrintable(ddf.path));
+            DBG_Printf(DBG_INFO, "DEV found DDF for " FMT_MAC ", path: %s, result: %d\n", FMT_MAC_CAST(event.deviceKey()), qPrintable(ddf.path), result);
         }
 
         if (result == 0)