From bcdc4570dd49ca4e1f2da368ee338a7b6ed9a2f4 Mon Sep 17 00:00:00 2001
From: Benjamin Prosnitz <bprosnitz@gmail.com>
Date: Tue, 15 Nov 2022 13:01:44 -0500
Subject: [PATCH] Fix panic when reading file with no row groups (#408)

---
 file.go                |   4 ++++
 testdata/empty.parquet | Bin 0 -> 90 bytes
 2 files changed, 4 insertions(+)
 create mode 100644 testdata/empty.parquet

diff --git a/file.go b/file.go
index 164c517..0dcbb1a 100644
--- a/file.go
+++ b/file.go
@@ -174,6 +174,10 @@ func OpenFile(r io.ReaderAt, size int64, options ...FileOption) (*File, error) {
 // this case the page index is not cached within the file, programs are expected
 // to make use of independently from the parquet package.
 func (f *File) ReadPageIndex() ([]format.ColumnIndex, []format.OffsetIndex, error) {
+	if len(f.metadata.RowGroups) == 0 {
+		return nil, nil, nil
+	}
+
 	columnIndexOffset := f.metadata.RowGroups[0].Columns[0].ColumnIndexOffset
 	offsetIndexOffset := f.metadata.RowGroups[0].Columns[0].OffsetIndexOffset
 	columnIndexLength := int64(0)
diff --git a/testdata/empty.parquet b/testdata/empty.parquet
new file mode 100644
index 0000000000000000000000000000000000000000..e36cbef74c5d4f5543f95bee1e4d2f8b223503db
GIT binary patch
literal 90
zcmWG=3^EjDlGHI}kl-&!EGjHbEs0Ohk1xv4FA-&85M>f&5M_{HElbQPO*I8FMHv{x
m7$kW#B%x|`)AJR|Qj3Z+^YavP5=&BxOBnnZ7#IS8rUC%s{T9vu

literal 0
HcmV?d00001