Always keep PtNodes that represent non-word info during GC.

Bug: 14119293
Change-Id: Ie50b341a512be6a6efe3e05b60e1d09560b01d1f

native/jni/src/suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_gc_event_listeners.cpp

@@ -29,10 +29,10 @@ bool DynamicPtGcEventListeners
     // PtNode is useless when the PtNode is not a terminal and doesn't have any not useless
     // children.
     bool isUselessPtNode = !ptNodeParams->isTerminal();
-    if (ptNodeParams->isTerminal()) {
+    if (ptNodeParams->isTerminal() && !ptNodeParams->representsNonWordInfo()) {
         bool needsToKeepPtNode = true;
-        if (!mPtNodeWriter->updatePtNodeProbabilityAndGetNeedsToKeepPtNodeAfterGC(ptNodeParams,
-                &needsToKeepPtNode)) {
+        if (!mPtNodeWriter->updatePtNodeProbabilityAndGetNeedsToKeepPtNodeAfterGC(
+                ptNodeParams, &needsToKeepPtNode)) {
             AKLOGE("Cannot update PtNode probability or get needs to keep PtNode after GC.");
             return false;
         }

native/jni/src/suggest/policyimpl/dictionary/structure/pt_common/pt_node_params.h

@@ -160,7 +160,8 @@ class PtNodeParams {
     }
 
     AK_FORCE_INLINE bool representsNonWordInfo() const {
-        return getCodePointCount() > 0 && CharUtils::isInUnicodeSpace(getCodePoints()[0]);
+        return getCodePointCount() > 0 && CharUtils::isInUnicodeSpace(getCodePoints()[0])
+                && isNotAWord();
     }
 
     // Parent node position

native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_writing_helper.cpp

@@ -213,13 +213,16 @@ bool Ver4PatriciaTrieWritingHelper::truncateUnigrams(
     // Delete unigrams.
     while (static_cast<int>(priorityQueue.size()) > maxUnigramCount) {
         const int ptNodePos = priorityQueue.top().getDictPos();
+        priorityQueue.pop();
         const PtNodeParams ptNodeParams =
                 ptNodeReader->fetchNodeInfoInBufferFromPtNodePos(ptNodePos);
+        if (ptNodeParams.representsNonWordInfo()) {
+            continue;
+        }
         if (!ptNodeWriter->markPtNodeAsWillBecomeNonTerminal(&ptNodeParams)) {
             AKLOGE("Cannot mark PtNode as willBecomeNonterminal. PtNode pos: %d", ptNodePos);
             return false;
         }
-        priorityQueue.pop();
     }
     return true;
 }