From 5ea0bbcfe0c30d68a59a5846dd4f5b3bcc83154e Mon Sep 17 00:00:00 2001
From: Eugen Sumin <eugen.sumin@kasten.io>
Date: Tue, 19 Mar 2024 10:43:52 +0100
Subject: [PATCH 1/2] fix: consistent handling of nil passed to any wrapping
 function

---
 errors.go      |  4 ++++
 errors_test.go | 10 ++++++++++
 2 files changed, 14 insertions(+)

diff --git a/errors.go b/errors.go
index 4edc764..a2b9d0f 100644
--- a/errors.go
+++ b/errors.go
@@ -44,6 +44,10 @@ func New(message string, details ...any) error {
 
 // Wrap returns a new errkitError that has the given message and err as the cause.
 func Wrap(err error, message string, details ...any) error {
+	if err == nil {
+		return nil
+	}
+
 	e := newError(errors.New(message), 2, details...)
 	e.cause = err
 	return e
diff --git a/errors_test.go b/errors_test.go
index 5d6a736..c6d851a 100644
--- a/errors_test.go
+++ b/errors_test.go
@@ -286,6 +286,16 @@ func TestErrorsWrapping(t *testing.T) {
 		if wrappedErr != nil {
 			t.Errorf("nil expected to be returned")
 		}
+
+		wrappedErr = errkit.Wrap(nil, "Some message")
+		if wrappedErr != nil {
+			t.Errorf("nil expected to be returned")
+		}
+
+		wrappedErr = errkit.WithStack(nil)
+		if wrappedErr != nil {
+			t.Errorf("nil expected to be returned")
+		}
 	})
 }
 

From e8dc80ea9553902b28aa2e6fa8e501a36e4aa712 Mon Sep 17 00:00:00 2001
From: Eugen Sumin <eugen.sumin@kasten.io>
Date: Wed, 20 Mar 2024 11:47:49 +0100
Subject: [PATCH 2/2] Document nil handling in `Wrap`, `WithStack` and
 `WithCause`

---
 README.md | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/README.md b/README.md
index a5b6b95..882bd60 100644
--- a/README.md
+++ b/README.md
@@ -28,6 +28,8 @@ func Foo() error {
 
 ### Adding stack trace
 If you are interested in adding information about the line and filename where the sentinel error happened, you can do the following:
+
+**NOTE**: While the `WithStack` will return `nil` if passed `err` equals `nil`, we do not consider this good practice and recommend checking the `err` value before invocation.
 ```go
 func Foo() error {
     ...
@@ -47,6 +49,8 @@ func Bar() error {
 
 ### Adding error cause information
 Sometimes you might be interested in returning a sentinel error, but also add some cause error to it, in such cases you can do the following:
+
+**NOTE**: While the `WithCause` will return `nil` if passed `err` equals `nil`, we do not consider this good practice and recommend checking the `err` value before invocation.
 ```go
 func FetchSomething(ID string) error {
     err := doSomething() // Here we have an error 
@@ -74,6 +78,8 @@ func FooBar() error {
 
 ### Wrapping an error with a high-level message
 Sometimes you might want to add some high-level information to an error before passing it up to the invoker.
+
+**NOTE**: While the `Wrap` will return `nil` if passed `err` equals `nil`, we do not consider this good practice and recommend checking the `err` value before invocation. 
 ```go
 func LoadProfile() error {
     err := makeAnApiCall()