From 960e339d3adb7cd3ac4b642a1c964e81074ff28d Mon Sep 17 00:00:00 2001
From: Richard Hopper <richardhopper@programmar.dev>
Date: Wed, 27 May 2026 19:51:04 +0000
Subject: [PATCH 1/2] docs: clarify Zero() is unrelated to encoding/json
 omitempty/omitzero

assert.Zero uses reflect.Zero to compare against the zero value of
a type. It does not use or check any IsZero() method, and is unrelated
to encoding/json's omitempty or omitzero struct tags.

This change adds documentation to assert.Zero() to prevent confusion
and includes a test with an IsZero()-implementing struct to verify
the behavior.

Closes #1759
---
 assert/assertions.go      |  4 ++++
 assert/assertions_test.go | 24 ++++++++++++++++++++++++
 2 files changed, 28 insertions(+)

diff --git a/assert/assertions.go b/assert/assertions.go
index 1419e4776..eff422cc4 100644
--- a/assert/assertions.go
+++ b/assert/assertions.go
@@ -1762,6 +1762,10 @@ func NotRegexp(t TestingT, rx interface{}, str interface{}, msgAndArgs ...interf
 }
 
 // Zero asserts that i is the zero value for its type.
+//
+// This is unrelated to [encoding/json]'s `omitzero` tag and does not
+// use or check the [encoding.TextMarshaler.IsZero] method. It simply
+// compares against [reflect.Zero] for the given type.
 func Zero(t TestingT, i interface{}, msgAndArgs ...interface{}) bool {
 	if h, ok := t.(tHelper); ok {
 		h.Helper()
diff --git a/assert/assertions_test.go b/assert/assertions_test.go
index 11642e096..aa9e5864e 100644
--- a/assert/assertions_test.go
+++ b/assert/assertions_test.go
@@ -2579,6 +2579,14 @@ func TestCallerInfoWithAutogeneratedFunctions(t *testing.T) {
 	})
 }
 
+// isZeroStruct demonstrates that assert.Zero uses reflect.Zero and is unrelated
+// to encoding/json's omitempty/omitzero or any IsZero() method.
+type isZeroStruct struct {
+	Value int
+}
+
+func (isZeroStruct) IsZero() bool { return false }
+
 func TestZero(t *testing.T) {
 	t.Parallel()
 
@@ -2593,6 +2601,22 @@ func TestZero(t *testing.T) {
 	}
 }
 
+func TestZeroNotIsZero(t *testing.T) {
+	t.Parallel()
+
+	// Verify that assert.Zero uses reflect.Zero and is unrelated to
+	// encoding/json's omitempty/omitzero or any IsZero() method.
+
+	mockT := new(testing.T)
+
+	// The zero value of the struct is "zero" per reflect.Zero,
+	// even though IsZero() would return false for Value==0.
+	True(t, Zero(mockT, isZeroStruct{Value: 0}))
+
+	// A non-zero struct value is "not zero"
+	False(t, Zero(mockT, isZeroStruct{Value: 42}))
+}
+
 func TestNotZero(t *testing.T) {
 	t.Parallel()
 

From f8b5a5b639b506e2000f194547498b1218caf975 Mon Sep 17 00:00:00 2001
From: Richard Hopper <richardhopper6767@gmail.com>
Date: Fri, 29 May 2026 03:23:07 +0000
Subject: [PATCH 2/2] regenerate Zerof docs to match Zero() documentation

---
 assert/assertion_format.go  | 4 ++++
 assert/assertion_forward.go | 4 ++++
 2 files changed, 8 insertions(+)

diff --git a/assert/assertion_format.go b/assert/assertion_format.go
index a19a89279..d5a7a3e63 100644
--- a/assert/assertion_format.go
+++ b/assert/assertion_format.go
@@ -870,6 +870,10 @@ func YAMLEqf(t TestingT, expected string, actual string, msg string, args ...int
 }
 
 // Zerof asserts that i is the zero value for its type.
+//
+// This is unrelated to [encoding/json]'s `omitzero` tag and does not
+// use or check the [encoding.TextMarshaler.IsZero] method. It simply
+// compares against [reflect.Zero] for the given type.
 func Zerof(t TestingT, i interface{}, msg string, args ...interface{}) bool {
 	if h, ok := t.(tHelper); ok {
 		h.Helper()
diff --git a/assert/assertion_forward.go b/assert/assertion_forward.go
index cd2a86061..a95f27755 100644
--- a/assert/assertion_forward.go
+++ b/assert/assertion_forward.go
@@ -1739,6 +1739,10 @@ func (a *Assertions) Zero(i interface{}, msgAndArgs ...interface{}) bool {
 }
 
 // Zerof asserts that i is the zero value for its type.
+//
+// This is unrelated to [encoding/json]'s `omitzero` tag and does not
+// use or check the [encoding.TextMarshaler.IsZero] method. It simply
+// compares against [reflect.Zero] for the given type.
 func (a *Assertions) Zerof(i interface{}, msg string, args ...interface{}) bool {
 	if h, ok := a.t.(tHelper); ok {
 		h.Helper()