From 136bdfe93f8830457651f88d4e423e39bc110485 Mon Sep 17 00:00:00 2001
From: Felipe Pena <felipensp@gmail.com>
Date: Sat, 19 Oct 2024 05:49:41 -0300
Subject: [PATCH] maps: use explicit map value cloning in `maps.merge_in_place`
 and `maps.merge` (fx #22564) (#22576)

---
 vlib/maps/maps.v            | 12 ++++++++++--
 vlib/maps/maps_clone_test.v | 36 ++++++++++++++++++++++++++++++++++++
 2 files changed, 46 insertions(+), 2 deletions(-)
 create mode 100644 vlib/maps/maps_clone_test.v

diff --git a/vlib/maps/maps.v b/vlib/maps/maps.v
index f28804aceac813..4d18730093b964 100644
--- a/vlib/maps/maps.v
+++ b/vlib/maps/maps.v
@@ -75,7 +75,11 @@ pub fn from_array[T](array []T) map[int]T {
 // Note that this function modifes `m1`, while `m2` will not be.
 pub fn merge_in_place[K, V](mut m1 map[K]V, m2 map[K]V) {
 	for k, v in m2 {
-		m1[k] = v
+		$if v is $map {
+			m1[k] = v.clone()
+		} $else {
+			m1[k] = v
+		}
 	}
 }
 
@@ -86,7 +90,11 @@ pub fn merge_in_place[K, V](mut m1 map[K]V, m2 map[K]V) {
 pub fn merge[K, V](m1 map[K]V, m2 map[K]V) map[K]V {
 	mut res := m1.clone()
 	for k, v in m2 {
-		res[k] = v
+		$if v is $map {
+			res[k] = v.clone()
+		} $else {
+			res[k] = v
+		}
 	}
 	return res
 }
diff --git a/vlib/maps/maps_clone_test.v b/vlib/maps/maps_clone_test.v
new file mode 100644
index 00000000000000..edc407a6b0fcc2
--- /dev/null
+++ b/vlib/maps/maps_clone_test.v
@@ -0,0 +1,36 @@
+import maps
+
+fn test_main() {
+	// mmm map declaration as mutable
+	mut mmm := map[string]map[string]int{}
+
+	// adding values to the map mmm
+	mmm['greet'] = {
+		'hello': 0
+	}
+	mmm['place'] = {
+		'world': 1
+	}
+	mmm['color']['orange'] = 2
+
+	// printing the map mmm
+	assert mmm.str() == "{'greet': {'hello': 0}, 'place': {'world': 1}, 'color': {'orange': 2}}"
+
+	// mmm2 map declaration as const
+	mmm2 := {
+		'name': {
+			'Diego': 3
+		}
+	}
+
+	// printing the map mmm2
+	assert mmm2.str() == "{'name': {'Diego': 3}}"
+
+	// Using the maps module functions
+	// use of maps.merge is commented but its behavior is the same as merge_in_place
+	// mmm = maps.merge(mmm, mmm2)
+	maps.merge_in_place(mut mmm, mmm2)
+
+	// printing again mmm to the standard output
+	assert mmm.str() == "{'greet': {'hello': 0}, 'place': {'world': 1}, 'color': {'orange': 2}, 'name': {'Diego': 3}}"
+}