From e8eeb9abe096b6a979e35b70ab85b218ebdcef63 Mon Sep 17 00:00:00 2001
From: Christian Thiel <christian@hansetag.com>
Date: Sun, 22 Sep 2024 16:10:01 +0200
Subject: [PATCH 1/2] Add NamespaceIdent.parent()

---
 crates/iceberg/src/catalog/mod.rs | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/crates/iceberg/src/catalog/mod.rs b/crates/iceberg/src/catalog/mod.rs
index aa2311b4a..63be3a69c 100644
--- a/crates/iceberg/src/catalog/mod.rs
+++ b/crates/iceberg/src/catalog/mod.rs
@@ -133,6 +133,16 @@ impl NamespaceIdent {
     pub fn inner(self) -> Vec<String> {
         self.0
     }
+
+    /// Get the parent of this namespace.
+    /// Returns None if this namespace only has a single element and thus has no parent.
+    pub fn parent(&self) -> Option<Self> {
+        if self.0.len() <= 1 {
+            None
+        } else {
+            Some(Self(self.0[..self.0.len() - 1].to_vec()))
+        }
+    }
 }
 
 impl AsRef<Vec<String>> for NamespaceIdent {
@@ -480,6 +490,17 @@ mod tests {
     };
     use crate::{NamespaceIdent, TableCreation, TableIdent, TableRequirement, TableUpdate};
 
+    #[test]
+    fn test_parent_namespace() {
+        let ns1 = NamespaceIdent::from_strs(vec!["ns1"]).unwrap();
+        let ns2 = NamespaceIdent::from_strs(vec!["ns1", "ns2"]).unwrap();
+        let ns3 = NamespaceIdent::from_strs(vec!["ns1", "ns2", "ns3"]).unwrap();
+
+        assert_eq!(ns1.parent(), None);
+        assert_eq!(ns2.parent(), Some(ns1.clone()));
+        assert_eq!(ns3.parent(), Some(ns2.clone()));
+    }
+
     #[test]
     fn test_create_table_id() {
         let table_id = TableIdent {

From 0a4584575b89d37485e74e98dd72667b51ca0e4e Mon Sep 17 00:00:00 2001
From: Christian Thiel <christian@hansetag.com>
Date: Mon, 23 Sep 2024 21:55:37 +0200
Subject: [PATCH 2/2] Use split_last

---
 crates/iceberg/src/catalog/mod.rs | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/crates/iceberg/src/catalog/mod.rs b/crates/iceberg/src/catalog/mod.rs
index 63be3a69c..54abe8083 100644
--- a/crates/iceberg/src/catalog/mod.rs
+++ b/crates/iceberg/src/catalog/mod.rs
@@ -137,11 +137,13 @@ impl NamespaceIdent {
     /// Get the parent of this namespace.
     /// Returns None if this namespace only has a single element and thus has no parent.
     pub fn parent(&self) -> Option<Self> {
-        if self.0.len() <= 1 {
-            None
-        } else {
-            Some(Self(self.0[..self.0.len() - 1].to_vec()))
-        }
+        self.0.split_last().and_then(|(_, parent)| {
+            if parent.is_empty() {
+                None
+            } else {
+                Some(Self(parent.to_vec()))
+            }
+        })
     }
 }