test: pin the chunk-size boundary, and say only what the narrowing does

The "4g" case re-entered the same comparison as "2g", so it pinned nothing;
mutating the guard from > to >= went undetected. Assert the boundary itself
instead.

The comment also claimed more than the code does. Chunk size 0 is a supported
mode (ChunkedDictionaryTest builds one deliberately) and 1g is a value the
guard accepts, so neither "4g" nor "5g" produces a wrong index: narrowing
substitutes a different size than the one configured, and only the negative
case fails.

Co-Authored-By: Claude Code <noreply@anthropic.com>

Author: LuciferYang

paimon-common/src/main/java/org/apache/paimon/fileindex/rangebitmap/RangeBitmapFileIndex.java

@@ -73,10 +73,9 @@ public Writer(DataType dataType, Options options) {
             KeyFactory factory = KeyFactory.create(dataType);
             String chunkSize = options.getString(CHUNK_SIZE, factory.defaultChunkSize());
             long bytes = MemorySize.parse(chunkSize).getBytes();
-            // the chunk size becomes an eagerly allocated per-chunk buffer, so anything beyond
-            // int range cannot work. Truncating is worse than rejecting: "2g" narrows to a
-            // negative int and crashes deep inside the writer, while "4g" narrows to 0 and
-            // "5g" to 1g, which build a silently wrong index instead of failing at all.
+            // the chunk size becomes an eagerly allocated per-chunk buffer, so it has to fit an
+            // int. Narrowing it silently substitutes a different size: "2g" becomes negative and
+            // fails only once the writer allocates, "4g" becomes 0 and "5g" becomes 1g.
             if (bytes > Integer.MAX_VALUE) {
                 throw new IllegalArgumentException(
                         String.format(

paimon-common/src/test/java/org/apache/paimon/fileindex/rangebitmap/RangeBitmapFileIndexTest.java

@@ -62,28 +62,22 @@ public class RangeBitmapFileIndexTest {
     public void testChunkSizeBeyondIntRangeRejected() {
         VarCharType varCharType = new VarCharType();
 
-        // "2g" narrows to a negative int, which crashes on the writer's first chunk allocation
-        Options negativeAfterNarrowing = new Options();
-        negativeAfterNarrowing.setString(RangeBitmapFileIndex.CHUNK_SIZE, "2g");
+        // the boundary is the whole guard: one byte past int range is rejected, int range itself
+        // is accepted. "2g" and "4g" would both only re-test the same comparison
+        Options justPastIntRange = new Options();
+        justPastIntRange.setString(RangeBitmapFileIndex.CHUNK_SIZE, "2147483648 bytes");
         assertThatThrownBy(
                         () ->
-                                new RangeBitmapFileIndex(varCharType, negativeAfterNarrowing)
+                                new RangeBitmapFileIndex(varCharType, justPastIntRange)
                                         .createWriter())
                 .isInstanceOf(IllegalArgumentException.class)
                 .hasMessageContaining("chunk-size");
 
-        // "4g" narrows to 0, which is the case worth guarding: it does not crash at all, it
-        // gives every key its own chunk and builds a silently bloated index
-        Options zeroAfterNarrowing = new Options();
-        zeroAfterNarrowing.setString(RangeBitmapFileIndex.CHUNK_SIZE, "4g");
-        assertThatThrownBy(
-                        () ->
-                                new RangeBitmapFileIndex(varCharType, zeroAfterNarrowing)
-                                        .createWriter())
-                .isInstanceOf(IllegalArgumentException.class)
-                .hasMessageContaining("chunk-size");
+        Options atIntRange = new Options();
+        atIntRange.setString(RangeBitmapFileIndex.CHUNK_SIZE, "2147483647 bytes");
+        assertThat(new RangeBitmapFileIndex(varCharType, atIntRange).createWriter()).isNotNull();
 
-        // a large but in-range chunk size still works
+        // a large but in-range chunk size still writes and serializes
         Options valid = new Options();
         valid.setString(RangeBitmapFileIndex.CHUNK_SIZE, "16mb");
         FileIndexWriter writer = new RangeBitmapFileIndex(varCharType, valid).createWriter();