Empty projection returns the wrong number of rows when column index is enabled

Discovered in Spark, when returning an empty projection from a Parquet file with filter pushdown enabled (typically when doing filter + count), Parquet-Mr returns a wrong number of rows with column index enabled. When the column index feature is disabled, the result is correct.

This happens due to the following:
1. ParquetFileReader::getFilteredRowCount() ( selects row ranges to calculate the row count when column index is enabled.
1. In ColumnIndexFilter ( we filter row ranges and pass the set of paths which in this case is empty.
1. When evaluating the filter, if the column path is not in the set, we would return an empty list of rows ([https://github.com/apache/parquet-mr/blob/0819356a9dafd2ca07c5eab68e2bffeddc3bd3d9/parquet-column/src/main/java/org/apache/parquet/internal/filter2/columnindex/ColumnIndexFilter.java#L178)](https://github.com/apache/parquet-mr/blob/0819356a9dafd2ca07c5eab68e2bffeddc3bd3d9/parquet-column/src/main/java/org/apache/parquet/internal/filter2/columnindex/ColumnIndexFilter.java#L178).) which is always the case for an empty projection.
1. This results in the incorrect number of records reported by the library.

I will provide the full repro later.

 

 

**Reporter**: [Ivan Sadikov](https://issues.apache.org/jira/secure/ViewProfile.jspa?name=ivan.sadikov)
#### Related issues:
- [Filtered parquet data frame count() and show() produce inconsistent results when spark.sql.parquet.filterPushdown is true](https://issues.apache.org/jira/browse/SPARK-39833) (is related to)

_{**Note**: *This issue was originally created as [PARQUET-2170](https://issues.apache.org/jira/browse/PARQUET-2170). Please see the [migration documentation](https://issues.apache.org/jira/browse/PARQUET-2502) for further details.*}

从 ParquetFileReader::getFilteredRowCount() 和 ColumnIndexFilter 开始，跟踪空列路径集合在行范围评估中的处理过程。完整复现用例可用后，复现 Spark 的过滤加计数场景，然后验证带有列索引和 filter pushdown 的空投影是否报告正确的行数。

由索引模型根据 Issue 内容生成。