Print a more user-friendly error message when using --hotwords-file. (#344)

@@ -46,7 +46,17 @@ bool OfflineRecognizerConfig::Validate() const {
                        max_active_paths);
       return false;
     }
-    if (!lm_config.Validate()) return false;
+    if (!lm_config.Validate()) {
+      return false;
+    }
+  }
+
+  if (!hotwords_file.empty() && decoding_method != "modified_beam_search") {
+    SHERPA_ONNX_LOGE(
+        "Please use --decoding-method=modified_beam_search if you"
+        " provide --hotwords-file. Given --decoding-method=%s",
+        decoding_method.c_str());
+    return false;
   }
 
   return model_config.Validate();

@@ -156,8 +156,9 @@ class OnlineRecognizerTransducerImpl : public OnlineRecognizerImpl {
     bool has_context_graph = false;
 
     for (int32_t i = 0; i != n; ++i) {
-      if (!has_context_graph && ss[i]->GetContextGraph())
+      if (!has_context_graph && ss[i]->GetContextGraph()) {
         has_context_graph = true;
+      }
 
       const auto num_processed_frames = ss[i]->GetNumProcessedFrames();
       std::vector<float> features =

@@ -102,8 +102,20 @@ bool OnlineRecognizerConfig::Validate() const {
                        max_active_paths);
       return false;
     }
-    if (!lm_config.Validate()) return false;
+
+    if (!lm_config.Validate()) {
+      return false;
+    }
   }
+
+  if (!hotwords_file.empty() && decoding_method != "modified_beam_search") {
+    SHERPA_ONNX_LOGE(
+        "Please use --decoding-method=modified_beam_search if you"
+        " provide --hotwords-file. Given --decoding-method=%s",
+        decoding_method.c_str());
+    return false;
+  }
+
   return model_config.Validate();
 }
 

-from typing import Dict, List, Optional
-
 from _sherpa_onnx import (
     CircularBuffer,
     Display,

@@ -102,6 +102,12 @@ class OfflineRecognizer(object):
             feature_dim=feature_dim,
         )
 
+        if len(hotwords_file) > 0 and decoding_method != "modified_beam_search":
+            raise ValueError(
+                "Please use --decoding-method=modified_beam_search when using "
+                f"--hotwords-file. Currently given: {decoding_method}"
+            )
+
         recognizer_config = OfflineRecognizerConfig(
             feat_config=feat_config,
             model_config=model_config,

@@ -132,6 +132,12 @@ class OnlineRecognizer(object):
             rule3_min_utterance_length=rule3_min_utterance_length,
         )
 
+        if len(hotwords_file) > 0 and decoding_method != "modified_beam_search":
+            raise ValueError(
+                "Please use --decoding-method=modified_beam_search when using "
+                f"--hotwords-file. Currently given: {decoding_method}"
+            )
+
         recognizer_config = OnlineRecognizerConfig(
             feat_config=feat_config,
             model_config=model_config,