From 67aede4364aef515010e3220c608fcf229d5e8af Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B8rn=20Erik=20Pedersen?=
 <bjorn.erik.pedersen@gmail.com>
Date: Thu, 21 May 2026 10:36:10 +0200
Subject: [PATCH] tpl/collections: Make dict return nil when no values are
 provided

---
 common/hashing/hashing_test.go                 |  9 +++++++++
 tpl/collections/collections.go                 | 10 ++++++++++
 .../collections_integration_test.go            | 18 ++++++++++++++++++
 3 files changed, 37 insertions(+)

diff --git a/common/hashing/hashing_test.go b/common/hashing/hashing_test.go
index de2fed8f0..f98ab7d51 100644
--- a/common/hashing/hashing_test.go
+++ b/common/hashing/hashing_test.go
@@ -62,6 +62,15 @@ func TestXxHashFromString(t *testing.T) {
 	c.Assert(got, qt.Equals, uint64(7148569436472236994))
 }
 
+func TestHashNilMapVsEmptyMap(t *testing.T) {
+	c := qt.New(t)
+
+	var m1 map[string]any = nil
+	m2 := map[string]any{}
+
+	c.Assert(HashString(m1), qt.Equals, HashString(m2))
+}
+
 func TestXxHashFromStringHexEncoded(t *testing.T) {
 	c := qt.New(t)
 	s := "The quick brown fox jumps over the lazy dog"
diff --git a/tpl/collections/collections.go b/tpl/collections/collections.go
index 04840f8c4..2563a60f1 100644
--- a/tpl/collections/collections.go
+++ b/tpl/collections/collections.go
@@ -157,7 +157,17 @@ func (ns *Namespace) Delimit(ctx context.Context, l, sep any, last ...any) (stri
 // Dictionary creates a new map from the given parameters by
 // treating values as key-value pairs.  The number of values must be even.
 // The keys can be string slices, which will create the needed nested structure.
+// If no values are provided, nil will be returned.
 func (ns *Namespace) Dictionary(values ...any) (map[string]any, error) {
+	if len(values) == 0 {
+		// A common construct is to do
+		//     {{ $opts := dict }}
+		// And then conditionally assign it if some condition is set.
+		// The only difference between this and an empty map is that this cannot be written to,
+		// which is not something we do in Hugo (or: If we do, that's a bug).
+		// This saves us ~48 bytes in memory allocation on 64-bit architectures.
+		return nil, nil
+	}
 	if len(values)%2 != 0 {
 		return nil, errors.New("invalid dictionary call")
 	}
diff --git a/tpl/collections/collections_integration_test.go b/tpl/collections/collections_integration_test.go
index 6cd9639a7..59cb51640 100644
--- a/tpl/collections/collections_integration_test.go
+++ b/tpl/collections/collections_integration_test.go
@@ -653,3 +653,21 @@ All.
 		}
 	})
 }
+
+func TestEmptyDictShouldBeNil(t *testing.T) {
+	t.Parallel()
+
+	files := `
+-- hugo.toml --
+-- layouts/home.html --
+{{ $d := dict }}
+{{ printf "dict: %T %t %d" $d (eq $d nil) (len $d) }}
+{{ range $d }}FAIL{{ end }}
+index: {{ index $d "foo" }}|
+{{ $d2 := dict "foo" "bar" }}
+{{ $d3 := merge $d $d2 }}
+{{ printf "d3: %v" $d3 }}|
+`
+
+	hugolib.Test(t, files).AssertFileContent("public/index.html", "dict: map[string]interface {} true 0", "! FAIL", "index: |", "d3: map[foo:bar]|")
+}