Clean up QWP recovery scaffolding

Remove the unused symbol-mirror append helper. Reuse shared wire parsing and deletion-assured temporary directory fixtures in recovery tests.

Author: glasstiger

core/src/main/java/io/questdb/client/cutlass/qwp/client/sf/cursor/CursorWebSocketSendLoop.java

@@ -43,7 +43,6 @@
 import io.questdb.client.std.CharSequenceLongHashMap;
 import io.questdb.client.std.MemoryTag;
 import io.questdb.client.std.QuietCloseable;
-import io.questdb.client.std.str.Utf8s;
 import io.questdb.client.std.Unsafe;
 import org.jetbrains.annotations.TestOnly;
 import org.slf4j.Logger;
@@ -2460,32 +2459,6 @@ private void accumulateSentDict(long payloadAddr, int payloadLen, int deltaStart
         sentDictIndexedCount = sentDictCount;
     }
 
-    /**
-     * Appends one symbol to the sent-dictionary mirror in wire form
-     * ({@code [len varint][utf8]}), advancing {@code sentDictCount}. Seeds the mirror at
-     * construction; {@link #accumulateSentDict} extends it from live frames thereafter.
-     */
-    private void appendSymbolToMirror(CharSequence symbol) {
-        if (forceMirrorSeedFailureForTest) {
-            // Simulate a native realloc OOM on the seed path (see the field).
-            throw new LineSenderException("simulated mirror seed allocation failure (test only)");
-        }
-        int utf8Len = Utf8s.utf8Bytes(symbol);
-        int wireLen = NativeBufferWriter.varintSize(utf8Len) + utf8Len;
-        ensureSentDictCapacity((long) sentDictBytesLen + wireLen);
-        ensureSentDictEntryEndsCapacity((long) sentDictCount + 1L);
-        long p = NativeBufferWriter.writeVarint(sentDictBytesAddr + sentDictBytesLen, utf8Len);
-        if (utf8Len > 0) {
-            Utf8s.strCpyUtf8(symbol, p, utf8Len);
-        }
-        sentDictBytesLen += wireLen;
-        Unsafe.getUnsafe().putInt(
-                sentDictEntryEndsAddr + (long) sentDictCount * Integer.BYTES,
-                sentDictBytesLen);
-        sentDictCount++;
-        sentDictIndexedCount = sentDictCount;
-    }
-
     private void ensureSentDictCapacity(long required) {
         if (sentDictBytesCapacity >= required) {
             return;

core/src/test/java/io/questdb/client/test/cutlass/qwp/client/DeltaDictRecoveryTest.java

@@ -35,10 +35,11 @@
 import io.questdb.client.test.cutlass.qwp.websocket.TestWebSocketServer;
 import io.questdb.client.test.tools.DelegatingFilesFacade;
 import io.questdb.client.test.tools.TestUtils;
-import org.junit.After;
 import org.junit.Assert;
 import org.junit.Before;
+import org.junit.Rule;
 import org.junit.Test;
+import org.junit.rules.TemporaryFolder;
 
 import java.io.IOException;
 import java.nio.ByteBuffer;
@@ -71,17 +72,15 @@ public class DeltaDictRecoveryTest {
 
     private static final int DISTINCT_SYMBOLS = 8;
     private static final int ROWS = 40;
+
+    @Rule
+    public final TemporaryFolder temporaryFolder = TemporaryFolder.builder().assureDeletion().build();
+
     private String sfDir;
 
     @Before
     public void setUp() {
-        sfDir = Paths.get(System.getProperty("java.io.tmpdir"),
-                "qdb-delta-recov-" + System.nanoTime()).toString();
-    }
-
-    @After
-    public void tearDown() {
-        TestUtils.removeTmpDirRec(sfDir);
+        sfDir = temporaryFolder.getRoot().toPath().resolve("qdb-delta-recovery").toString();
     }
 
     @Test