Reviewed verification allocations

- Dependency hashing reuses one read buffer per artifact
- Hash tests cover mixed entry sizes

buildSrc/src/main/java/art/arcane/iris/buildtools/GenerationBuildRevision.java

@@ -231,11 +231,11 @@ public final class GenerationBuildRevision {
                     throw new IOException("Duplicate dependency artifact entry: " + name);
                 }
             }
+            byte[] buffer = new byte[16 * 1024];
             for (Map.Entry<String, ZipEntry> entry : entries.entrySet()) {
                 update(digest, entry.getKey());
                 try (InputStream input = zip.getInputStream(entry.getValue())) {
                     MessageDigest content = digest();
-                    byte[] buffer = new byte[16 * 1024];
                     int read;
                     while ((read = input.read(buffer)) != -1) {
                         content.update(buffer, 0, read);

buildSrc/src/test/java/GenerationBuildRevisionTest.java

@@ -58,6 +58,22 @@ public class GenerationBuildRevisionTest {
                 GenerationBuildRevision.capture(fixture.options(), dependencies)));
     }
 
+    @Test
+    public void hashesLargeShortAndEmptyEntriesIndependently() throws Exception {
+        Path dependency = temporary.newFile("multiple-entries.jar").toPath();
+        Map<String, String> contents = Map.of("example/Large.class", "abc".repeat(11_000),
+                "example/Short.class", "tail", "example/Zero.class", "");
+        try (ZipOutputStream output = new ZipOutputStream(Files.newOutputStream(dependency))) {
+            for (String name : List.of("example/Zero.class", "example/Short.class", "example/Large.class")) {
+                output.putNextEntry(new ZipEntry(name));
+                output.write(contents.get(name).getBytes(StandardCharsets.UTF_8));
+                output.closeEntry();
+            }
+        }
+        assertEquals("49217af891afa3111d1f70a390acacc8bad700528b61b1ecc5637c060aeb52cd",
+                GenerationBuildRevision.artifactHash(dependency));
+    }
+
     @Test
     public void rejectsChangedAddedAndDeletedGenerationSources() throws Exception {
         Fixture fixture = fixture();