Always encrypt when uniform encryption

Author: rok

parquet/src/file/metadata/writer.rs

@@ -758,17 +758,11 @@ impl MetadataObjectWriter {
         let encryptor = match column_chunk.column_crypto_metadata.as_deref() {
             None => None,
             Some(ColumnCryptoMetaData::ENCRYPTION_WITH_FOOTER_KEY) => {
-                let is_footer_encrypted = file_encryptor.properties().encrypt_footer();
-
-                // When uniform encryption is used the footer is already encrypted,
-                // so the column chunk does not need additional encryption.
-                // Except if we're in plaintext footer mode, then we need to encrypt
-                // the column metadata here.
-                if !is_footer_encrypted {
-                    Some(file_encryptor.get_footer_encryptor()?)
-                } else {
-                    None
-                }
+                // We always encrypt column metadata separately and store in
+                // encrypted_column_metadata. This allows skipping the plaintext meta_data
+                // field in the writer to reduce footer size. If encrypted_column_metadata
+                // were not set, the reader would not be able to read the column metadata.
+                Some(file_encryptor.get_footer_encryptor()?)
             }
             Some(ColumnCryptoMetaData::ENCRYPTION_WITH_COLUMN_KEY(col_key)) => {
                 let column_path = col_key.path_in_schema.join(".");