HIVE-29342: Iceberg: [V3] Display initial and write defaults in describe formatted column output

Author: tanishq-chugh

iceberg/iceberg-handler/src/test/queries/positive/iceberg_defaults_in_desc_cols.q

@@ -0,0 +1,54 @@
+-- Mask random uuid
+--! qt:replace:/(\s+uuid\s+)\S+(\s*)/$1#Masked#$2/
+-- Mask a random snapshot id
+--! qt:replace:/(\s+current-snapshot-id\s+)\S+(\s*)/$1#Masked#/
+-- Mask added file size
+--! qt:replace:/(\S\"added-files-size\\\":\\\")(\d+)(\\\")/$1#Masked#$3/
+-- Mask total file size
+--! qt:replace:/(\S\"total-files-size\\\":\\\")(\d+)(\\\")/$1#Masked#$3/
+-- Mask current-snapshot-timestamp-ms
+--! qt:replace:/(\s+current-snapshot-timestamp-ms\s+)\S+(\s*)/$1#Masked#$2/
+
+CREATE TABLE ice_parq (
+  id INT)
+STORED BY ICEBERG stored as parquet
+TBLPROPERTIES ('format-version'='3');
+
+INSERT INTO ice_parq (id) VALUES (1);
+
+ALTER TABLE ice_parq ADD COLUMNS (point STRUCT<x:INT, y:INT> DEFAULT 'x:100,y:99',
+  name STRING DEFAULT 'unknown',
+  age INT DEFAULT 25);
+
+INSERT INTO ice_parq (id) VALUES (2);
+
+SELECT * FROM ice_parq ORDER BY id;
+
+DESCRIBE FORMATTED ice_parq;
+
+DESCRIBE FORMATTED ice_parq id;
+DESCRIBE FORMATTED ice_parq point;
+DESCRIBE FORMATTED ice_parq name;
+DESCRIBE FORMATTED ice_parq age;
+
+CREATE TABLE ice_orc (
+  id INT)
+STORED BY ICEBERG stored as orc
+TBLPROPERTIES ('format-version'='3');
+
+INSERT INTO ice_orc (id) VALUES (1);
+
+ALTER TABLE ice_orc ADD COLUMNS (point STRUCT<x:INT, y:INT> DEFAULT 'x:100,y:99',
+  name STRING DEFAULT 'unknown',
+  age INT DEFAULT 25);
+
+INSERT INTO ice_orc (id) VALUES (2);
+
+SELECT * FROM ice_orc ORDER BY id;
+
+DESCRIBE FORMATTED ice_orc;
+
+DESCRIBE FORMATTED ice_orc id;
+DESCRIBE FORMATTED ice_orc point;
+DESCRIBE FORMATTED ice_orc name;
+DESCRIBE FORMATTED ice_orc age;