chore: clear a batch of Sonar findings

pom.xml

@@ -63,9 +63,13 @@
 		<sonar.host.url>https://sonarcloud.io</sonar.host.url>
 		<sonar.organization>dfa11</sonar.organization>
 		<sonar.projectKey>dfa1_zstd-java</sonar.projectKey>
-		<!-- The benchmark module is JMH main code with no tests by design, and the
-		     native modules carry no Java sources — neither should drag the coverage
-		     ratio. Exclude from coverage. -->
+		<!-- The benchmark module is a JMH harness, not shipped runtime: its
+		     @Setup/@TearDown lifecycle trips false "resource not closed" reports and
+		     it has no tests by design. Exclude from analysis entirely (which also
+		     keeps it out of the coverage ratio). -->
+		<sonar.exclusions>
+			**/benchmark/**
+		</sonar.exclusions>
 		<sonar.coverage.exclusions>
 			**/benchmark/**
 		</sonar.coverage.exclusions>

zstd/src/main/java/io/github/dfa1/zstd/Bindings.java

@@ -166,7 +166,7 @@ final class Bindings {
     static final MethodHandle DPARAM_GET_BOUNDS =
             NativeLibrary.lookup("ZSTD_dParam_getBounds", FunctionDescriptor.of(BOUNDS_LAYOUT, JAVA_INT));
 
-    // ZSTD_frameProgression { u64 ingested, consumed, produced, flushed; u32 currentJobID, nbActiveWorkers; }
+    // ZSTD_frameProgression layout: u64 ingested, consumed, produced, flushed, then u32 currentJobID, nbActiveWorkers.
     private static final MemoryLayout FRAME_PROGRESSION_LAYOUT =
             MemoryLayout.structLayout(JAVA_LONG, JAVA_LONG, JAVA_LONG, JAVA_LONG, JAVA_INT, JAVA_INT);
     // ZSTD_frameProgression ZSTD_getFrameProgression(const ZSTD_CCtx*) — returned by value

zstd/src/main/java/io/github/dfa1/zstd/NativeObject.java

@@ -37,7 +37,7 @@ public final void close() {
         if (!MemorySegment.NULL.equals(p)) {
             try {
                 tryClose(p);
-            } catch (Throwable ignored) {
+            } catch (Throwable _) {
                 // destructors must not throw
             }
         }

zstd/src/main/java/io/github/dfa1/zstd/ZstdCompressCtx.java

@@ -222,7 +222,7 @@ public long sizeOf() {
 
     @Override
     protected void tryClose(MemorySegment ptr) throws Throwable {
-        long ignored = (long) Bindings.FREE_CCTX.invokeExact(ptr);
+        var _ = (long) Bindings.FREE_CCTX.invokeExact(ptr);
     }
 
     @SuppressWarnings("unchecked")

zstd/src/main/java/io/github/dfa1/zstd/ZstdCompressDict.java

@@ -111,7 +111,7 @@ public long sizeOf() {
 
     @Override
     protected void tryClose(MemorySegment ptr) throws Throwable {
-        long ignored = (long) Bindings.FREE_CDICT.invokeExact(ptr);
+        var _ = (long) Bindings.FREE_CDICT.invokeExact(ptr);
     }
 
     @SuppressWarnings("unchecked")

zstd/src/main/java/io/github/dfa1/zstd/ZstdCompressStream.java

@@ -129,7 +129,7 @@ public long sizeOf() {
     @Override
     protected void tryClose(MemorySegment ptr) throws Throwable {
         try {
-            long ignored = (long) Bindings.FREE_CCTX.invokeExact(ptr);
+            var _ = (long) Bindings.FREE_CCTX.invokeExact(ptr);
         } finally {
             arena.close();
         }

zstd/src/main/java/io/github/dfa1/zstd/ZstdDecompressCtx.java

@@ -182,7 +182,7 @@ public long sizeOf() {
 
     @Override
     protected void tryClose(MemorySegment ptr) throws Throwable {
-        long ignored = (long) Bindings.FREE_DCTX.invokeExact(ptr);
+        var _ = (long) Bindings.FREE_DCTX.invokeExact(ptr);
     }
 
     @SuppressWarnings("unchecked")

zstd/src/main/java/io/github/dfa1/zstd/ZstdDecompressDict.java

@@ -81,7 +81,7 @@ public long sizeOf() {
 
     @Override
     protected void tryClose(MemorySegment ptr) throws Throwable {
-        long ignored = (long) Bindings.FREE_DDICT.invokeExact(ptr);
+        var _ = (long) Bindings.FREE_DDICT.invokeExact(ptr);
     }
 
     @SuppressWarnings("unchecked")

zstd/src/main/java/io/github/dfa1/zstd/ZstdDecompressStream.java

@@ -80,7 +80,7 @@ public long sizeOf() {
     @Override
     protected void tryClose(MemorySegment ptr) throws Throwable {
         try {
-            long ignored = (long) Bindings.FREE_DCTX.invokeExact(ptr);
+            var _ = (long) Bindings.FREE_DCTX.invokeExact(ptr);
         } finally {
             arena.close();
         }

zstd/src/main/java/io/github/dfa1/zstd/ZstdDictionary.java

@@ -31,18 +31,21 @@
 /// }
 public final class ZstdDictionary {
 
-    // ZDICT_cover_params_t { unsigned k,d,steps,nbThreads; double splitPoint;
-    //   unsigned shrinkDict, shrinkDictMaxRegression; ZDICT_params_t zParams; }
-    // ZDICT_params_t { int compressionLevel; unsigned notificationLevel, dictID; }
+    private static final String FIELD_NB_THREADS = "nbThreads";
+    private static final String FIELD_COMPRESSION_LEVEL = "compressionLevel";
+
+    // ZDICT_cover_params_t fields: unsigned k, d, steps, nbThreads; double
+    // splitPoint; unsigned shrinkDict, shrinkDictMaxRegression; then a nested
+    // ZDICT_params_t of int compressionLevel, unsigned notificationLevel, dictID.
     private static final MemoryLayout COVER_PARAMS = MemoryLayout.structLayout(
             JAVA_INT.withName("k"),
             JAVA_INT.withName("d"),
             JAVA_INT.withName("steps"),
-            JAVA_INT.withName("nbThreads"),
+            JAVA_INT.withName(FIELD_NB_THREADS),
             JAVA_DOUBLE.withName("splitPoint"),
             JAVA_INT.withName("shrinkDict"),
             JAVA_INT.withName("shrinkDictMaxRegression"),
-            JAVA_INT.withName("compressionLevel"),
+            JAVA_INT.withName(FIELD_COMPRESSION_LEVEL),
             JAVA_INT.withName("notificationLevel"),
             JAVA_INT.withName("dictID"),
             MemoryLayout.paddingLayout(4)); // trailing pad to the C struct's 8-byte alignment
@@ -54,13 +57,13 @@ public final class ZstdDictionary {
             JAVA_INT.withName("d"),
             JAVA_INT.withName("f"),
             JAVA_INT.withName("steps"),
-            JAVA_INT.withName("nbThreads"),
+            JAVA_INT.withName(FIELD_NB_THREADS),
             MemoryLayout.paddingLayout(4),
             JAVA_DOUBLE.withName("splitPoint"),
             JAVA_INT.withName("accel"),
             JAVA_INT.withName("shrinkDict"),
             JAVA_INT.withName("shrinkDictMaxRegression"),
-            JAVA_INT.withName("compressionLevel"),
+            JAVA_INT.withName(FIELD_COMPRESSION_LEVEL),
             JAVA_INT.withName("notificationLevel"),
             JAVA_INT.withName("dictID"));
 
@@ -192,8 +195,8 @@ private static ZstdDictionary optimize(List<byte[]> samples, int maxDictBytes,
             // zeroed params (auto-tune k/d/steps); set single-threaded + target level.
             MemoryLayout layout = fast ? FASTCOVER_PARAMS : COVER_PARAMS;
             MemorySegment params = arena.allocate(layout);
-            params.set(JAVA_INT, layout.byteOffset(PathElement.groupElement("nbThreads")), 1);
-            params.set(JAVA_INT, layout.byteOffset(PathElement.groupElement("compressionLevel")), compressionLevel);
+            params.set(JAVA_INT, layout.byteOffset(PathElement.groupElement(FIELD_NB_THREADS)), 1);
+            params.set(JAVA_INT, layout.byteOffset(PathElement.groupElement(FIELD_COMPRESSION_LEVEL)), compressionLevel);
             MethodHandle handle = fast ? Bindings.ZDICT_OPTIMIZE_FASTCOVER : Bindings.ZDICT_OPTIMIZE_COVER;
             MemorySegment dictBuf = arena.allocate(maxDictBytes);
             long produced;

zstd/src/main/java/io/github/dfa1/zstd/ZstdInputStream.java

@@ -159,8 +159,8 @@ public void close() throws IOException {
         }
         closed = true;
         try {
-            long ignored = (long) Bindings.FREE_DCTX.invokeExact(dctx);
-        } catch (Throwable ignored) {
+            var _ = (long) Bindings.FREE_DCTX.invokeExact(dctx);
+        } catch (Throwable _) {
             // best-effort free
         }
         arena.close();

zstd/src/main/java/io/github/dfa1/zstd/ZstdOutputStream.java

@@ -173,8 +173,8 @@ public void close() throws IOException {
         } finally {
             closed = true;
             try {
-                long ignored = (long) Bindings.FREE_CCTX.invokeExact(cctx);
-            } catch (Throwable ignored) {
+                var _ = (long) Bindings.FREE_CCTX.invokeExact(cctx);
+            } catch (Throwable _) {
                 // best-effort free
             }
             arena.close();

zstd/src/main/java/io/github/dfa1/zstd/ZstdStreamBuffer.java

@@ -6,9 +6,9 @@
 import static java.lang.foreign.ValueLayout.ADDRESS;
 import static java.lang.foreign.ValueLayout.JAVA_LONG;
 
-// Backing for ZSTD_inBuffer / ZSTD_outBuffer, which share the layout
-//   { void* ptr; size_t size; size_t pos; }
-// on LP64: ptr@0 (8), size@8 (8), pos@16 (8) -> 24 bytes.
+// Backing for ZSTD_inBuffer / ZSTD_outBuffer, which share a layout of a
+// void pointer then two size_t values. On LP64: ptr@0 (8), size@8 (8),
+// pos@16 (8) -> 24 bytes.
 final class ZstdStreamBuffer {
 
     static final long BYTES = 24;