From 294ccdeb257203af1ba82cadf6af211b50a00738 Mon Sep 17 00:00:00 2001
From: Dan Jones <danjones@goodevilgenius.org>
Date: Tue, 30 Sep 2025 15:49:36 -0500
Subject: [PATCH 1/3] Add ErrorObject.Is method

---
 error.go      | 27 +++++++++++++++++++++++++++
 error_test.go | 14 ++++++++++++++
 2 files changed, 41 insertions(+)

diff --git a/error.go b/error.go
index e75b1de..7b675b4 100644
--- a/error.go
+++ b/error.go
@@ -112,6 +112,33 @@ func (e ErrorObject) Error() string {
 	return res.String()
 }
 
+// Is checks if this error matches the supplied error.
+// If err is not an ErrorObject, it always returns false.
+// It returns true if Code() and Message() are the same.
+// If err.Params() is non-nil, we also check that all the params match.
+// This way, we can check an error against a sentinel error, such as ErrLengthTooLong.
+func (e ErrorObject) Is(err error) bool {
+	eo, ok := err.(ErrorObject)
+	if !ok {
+		return false
+	}
+
+	if e.message != eo.message && e.code != eo.code {
+		return false
+	}
+
+	if len(eo.params) == 0 {
+		return true
+	}
+
+	for k, v := range e.params {
+		if eo.params[k] != v {
+			return false
+		}
+	}
+	return true
+}
+
 // Error returns the error string of Errors.
 func (es Errors) Error() string {
 	if len(es) == 0 {
diff --git a/error_test.go b/error_test.go
index e0985c5..cf0b2c8 100644
--- a/error_test.go
+++ b/error_test.go
@@ -115,6 +115,20 @@ func TestErrorObject_Params(t *testing.T) {
 	assert.Equal(t, err.Params(), p)
 }
 
+func TestErrorObject_Is(t *testing.T) {
+	err := ErrLengthOutOfRange.(ErrorObject)
+	err = err.SetParams(map[string]interface{}{"mix": 3, "max": 6}).(ErrorObject)
+
+	assert.True(t, err.Is(ErrLengthOutOfRange))
+	assert.True(t, errors.Is(err, ErrLengthOutOfRange))
+
+	err2 := ErrLengthOutOfRange.(ErrorObject)
+	err2 = err2.SetParams(map[string]interface{}{"min": 3, "max": 9}).(ErrorObject)
+
+	assert.False(t, err2.Is(err))
+	assert.False(t, errors.Is(err2, err))
+}
+
 func TestErrorObject_AddParam2(t *testing.T) {
 	p := map[string]interface{}{"key": "val"}
 	err := NewError("code", "A").(ErrorObject)

From 27de8ddbc472d3828eb31059f890ac54d32983a8 Mon Sep 17 00:00:00 2001
From: Dan Jones <danjones@goodevilgenius.org>
Date: Wed, 1 Oct 2025 08:14:57 -0500
Subject: [PATCH 2/3] Fix ErrorObject.Is logic

---
 error.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/error.go b/error.go
index 7b675b4..71a9a53 100644
--- a/error.go
+++ b/error.go
@@ -123,7 +123,7 @@ func (e ErrorObject) Is(err error) bool {
 		return false
 	}
 
-	if e.message != eo.message && e.code != eo.code {
+	if e.message != eo.message || e.code != eo.code {
 		return false
 	}
 

From 94ad41fe668ae115fe07daaf4ef90058fb8d2447 Mon Sep 17 00:00:00 2001
From: Dan Jones <danjones@goodevilgenius.org>
Date: Wed, 1 Oct 2025 08:15:27 -0500
Subject: [PATCH 3/3] Improve test coverage for ErrorObject.Is

---
 error_test.go | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/error_test.go b/error_test.go
index cf0b2c8..afc86e2 100644
--- a/error_test.go
+++ b/error_test.go
@@ -127,6 +127,17 @@ func TestErrorObject_Is(t *testing.T) {
 
 	assert.False(t, err2.Is(err))
 	assert.False(t, errors.Is(err2, err))
+
+	assert.False(t, err.Is(errors.New(err.message)))
+
+	err3 := ErrorObject{code: err.code, message: "hello"}
+	assert.False(t, err.Is(err3))
+
+	err4 := ErrorObject{code: "test_error", message: err.message}
+	assert.False(t, err.Is(err4))
+
+	err5 := ErrorObject{code: err.code, message: err.message, params: err.params}
+	assert.True(t, err.Is(err5))
 }
 
 func TestErrorObject_AddParam2(t *testing.T) {