fix(script_translator): excluded words cause crashes

Author: ksqsf

src/rime/gear/script_translator.cc

@@ -569,6 +569,7 @@ inline static bool prefer_user_phrase(
 }
 
 bool ScriptTranslation::PrepareCandidate() {
+iter_incremented:
   if (exhausted()) {
     candidate_source_ = kUninitialized;
     candidate_ = nullptr;
@@ -615,6 +616,10 @@ bool ScriptTranslation::PrepareCandidate() {
           })) {
     UserDictEntryIterator& uter = user_phrase_iter_->second;
     const auto& entry = uter.Peek();
+    if (!entry) {
+      ++user_phrase_iter_;
+      goto iter_incremented;
+    }
     DLOG(INFO) << "user phrase '" << entry->text
                << "', code length: " << user_phrase_code_length;
     candidate_source_ = kUserPhrase;
@@ -629,6 +634,10 @@ bool ScriptTranslation::PrepareCandidate() {
   } else if (phrase_code_length > 0) {
     DictEntryIterator& iter = phrase_iter_->second;
     const auto& entry = iter.Peek();
+    if (!entry) {
+      ++phrase_iter_;
+      goto iter_incremented;
+    }
     DLOG(INFO) << "phrase '" << entry->text
                << "', code length: " << phrase_code_length;
     candidate_source_ = kSysPhrase;