parquet: seek ahead skipped push decoder row groups

Teach the row-group frontier to seek ahead over queued row groups that
can be proven unreachable before instantiating the row-group builder.

Skip queued row groups when their selection slice is empty, when
offset/limit leaves no rows to read, or when the remaining limit is
already exhausted. Keep predicate-bearing row groups conservative and
stop at the first row group that may still need data.

Add a push decoder regression covering `try_next_reader` with
offset/limit so the frontier path is exercised directly.

Signed-off-by: Hippolyte Barraud <hippolyte.barraud@datadoghq.com>

Author: HippoBaro

parquet/src/arrow/push_decoder/mod.rs

@@ -1121,6 +1121,28 @@ mod test {
         expect_finished(decoder.try_decode());
     }
 
+    #[test]
+    fn test_decoder_try_next_reader_offset_limit() {
+        let mut decoder = ParquetPushDecoderBuilder::try_new_decoder(test_file_parquet_metadata())
+            .unwrap()
+            .with_offset(225)
+            .with_limit(20)
+            .build()
+            .unwrap();
+
+        let ranges = expect_needs_data(decoder.try_next_reader());
+        push_ranges_to_decoder(&mut decoder, ranges);
+
+        let reader = expect_data(decoder.try_next_reader());
+        let batches = reader
+            .map(|batch| batch.expect("expected decoded batch"))
+            .collect::<Vec<_>>();
+        let output = concat_batches(&TEST_BATCH.schema(), &batches).unwrap();
+        assert_eq!(output, TEST_BATCH.slice(225, 20));
+
+        expect_finished(decoder.try_next_reader());
+    }
+
     #[test]
     fn test_decoder_row_group_selection() {
         // take only the second row group