From ecd5127d1efc0a3d17fba05e2fe85743132d3b7f Mon Sep 17 00:00:00 2001
From: Claudia Meadows <contact@claudiameadows.dev>
Date: Mon, 11 Aug 2025 10:55:14 -0700
Subject: [PATCH 1/2] Fix the error message selection condition

I have no idea how this eluded me when I first wrote this.
---
 render/vnode.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/render/vnode.js b/render/vnode.js
index 215980f21..696295309 100644
--- a/render/vnode.js
+++ b/render/vnode.js
@@ -19,7 +19,7 @@ Vnode.normalizeChildren = function(input) {
 		for (var i = 1; i < input.length; i++) {
 			if ((input[i] != null && input[i].key != null) !== isKeyed) {
 				throw new TypeError(
-					isKeyed && (input[i] != null || typeof input[i] === "boolean")
+					isKeyed && (input[i] != null && typeof input[i] !== "boolean")
 						? "In fragments, vnodes must either all have keys or none have keys. You may wish to consider using an explicit keyed empty fragment, m.fragment({key: ...}), instead of a hole."
 						: "In fragments, vnodes must either all have keys or none have keys."
 				)

From f396bf134b36ff25c72aa55df289ce1121cfe328 Mon Sep 17 00:00:00 2001
From: Claudia Meadows <contact@claudiameadows.dev>
Date: Mon, 11 Aug 2025 12:59:11 -0700
Subject: [PATCH 2/2] Correct the fix, add tests just to make sure behavior was
 correct from the beginning

---
 render/tests/test-normalizeChildren.js | 64 ++++++++++++++++++++++++++
 render/vnode.js                        |  2 +-
 2 files changed, 65 insertions(+), 1 deletion(-)

diff --git a/render/tests/test-normalizeChildren.js b/render/tests/test-normalizeChildren.js
index a7cd5ba5b..68fab4c60 100644
--- a/render/tests/test-normalizeChildren.js
+++ b/render/tests/test-normalizeChildren.js
@@ -53,4 +53,68 @@ o.spec("normalizeChildren", function() {
 			])
 		}).throws(TypeError)
 	})
+	o("disallows mixed keys, ending with null", function() {
+		o(function() {
+			Vnode.normalizeChildren([
+				{key: 1},
+				null,
+			])
+		}).throws(TypeError)
+	})
+	o("disallows mixed keys, starting with null", function() {
+		o(function() {
+			Vnode.normalizeChildren([
+				{data: 1},
+				null,
+			])
+		}).throws(TypeError)
+	})
+	o("disallows mixed keys, ending with undefined", function() {
+		o(function() {
+			Vnode.normalizeChildren([
+				{key: 1},
+				undefined,
+			])
+		}).throws(TypeError)
+	})
+	o("disallows mixed keys, starting with undefined", function() {
+		o(function() {
+			Vnode.normalizeChildren([
+				{data: 1},
+				undefined,
+			])
+		}).throws(TypeError)
+	})
+	o("disallows mixed keys, ending with false", function() {
+		o(function() {
+			Vnode.normalizeChildren([
+				{key: 1},
+				false,
+			])
+		}).throws(TypeError)
+	})
+	o("disallows mixed keys, starting with false", function() {
+		o(function() {
+			Vnode.normalizeChildren([
+				{data: 1},
+				false,
+			])
+		}).throws(TypeError)
+	})
+	o("disallows mixed keys, ending with true", function() {
+		o(function() {
+			Vnode.normalizeChildren([
+				{key: 1},
+				true,
+			])
+		}).throws(TypeError)
+	})
+	o("disallows mixed keys, starting with true", function() {
+		o(function() {
+			Vnode.normalizeChildren([
+				{data: 1},
+				true,
+			])
+		}).throws(TypeError)
+	})
 })
diff --git a/render/vnode.js b/render/vnode.js
index 696295309..821b21bb2 100644
--- a/render/vnode.js
+++ b/render/vnode.js
@@ -19,7 +19,7 @@ Vnode.normalizeChildren = function(input) {
 		for (var i = 1; i < input.length; i++) {
 			if ((input[i] != null && input[i].key != null) !== isKeyed) {
 				throw new TypeError(
-					isKeyed && (input[i] != null && typeof input[i] !== "boolean")
+					isKeyed && (input[i] == null || typeof input[i] === "boolean")
 						? "In fragments, vnodes must either all have keys or none have keys. You may wish to consider using an explicit keyed empty fragment, m.fragment({key: ...}), instead of a hole."
 						: "In fragments, vnodes must either all have keys or none have keys."
 				)