From 406f831be8514c6b38f2027dfe5c88072800771e Mon Sep 17 00:00:00 2001
From: Komu Wairagu <komuw05@gmail.com>
Date: Tue, 21 Feb 2023 17:53:08 +0300
Subject: [PATCH] issues/25: zero value pointers should not panic (#37)

What:
- Zero value pointers should not panic

Why:
- Fixes: https://github.com/komuw/kama/issues/25
---
 CHANGELOG.md |  1 +
 README.md    |  8 ++++----
 kama_test.go |  6 ++++++
 vars.go      |  8 ++++++++
 vars_test.go | 12 ++++++++++++
 5 files changed, 31 insertions(+), 4 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index af1435a..9efb703 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,7 @@ Most recent version is listed first.
 # v0.0.7
 - Update to Go 1.20: https://github.com/komuw/kama/pull/34
 - Better formatting for zero-length slices and maps: https://github.com/komuw/kama/pull/36
+- Zero value pointers should not panic: https://github.com/komuw/kama/pull/37
 
 # v0.0.6
 - Update dependencies: https://github.com/komuw/kama/pull/32
diff --git a/README.md b/README.md
index 346ab41..5604ecc 100644
--- a/README.md
+++ b/README.md
@@ -166,13 +166,13 @@ SNIPPET: &Request{
   Body: io.ReadCloser nil,
   GetBody: func() (io.ReadCloser, error),
   ContentLength: int64(0),
-  TransferEncoding: []string{},
+  TransferEncoding: []string{(nil)},
   Close: false,
   Host: "example.com",
-  Form: url.Values{},
-  PostForm: url.Values{},
+  Form: url.Values{(nil)},
+  PostForm: url.Values{(nil)},
   MultipartForm: *multipart.Form(nil),
-  Trailer: http.Header{},
+  Trailer: http.Header{(nil)},
   RemoteAddr: "",
   RequestURI: "",
   TLS: *tls.ConnectionState(nil),
diff --git a/kama_test.go b/kama_test.go
index 6730efa..e0af309 100644
--- a/kama_test.go
+++ b/kama_test.go
@@ -124,12 +124,18 @@ func (h myHandler) ServeHTTP(http.ResponseWriter, *http.Request) {
 func TestStdlibTypes(t *testing.T) {
 	t.Parallel()
 
+	var req http.Request
+	var reqPtr *http.Request
+
 	tt := []interface{}{
 		errors.New,
 		reflect.Value{},
 		http.Handle,
 		http.HandleFunc,
 		http.Handler(myHandler{}),
+		req,
+		&req,
+		reqPtr,
 	}
 
 	for _, v := range tt {
diff --git a/vars.go b/vars.go
index 52659c0..d511737 100644
--- a/vars.go
+++ b/vars.go
@@ -32,6 +32,14 @@ func newVari(i interface{}) vari {
 			Val:       dump(valueOfi, hideZeroValues, indentLevel),
 		}
 	}
+	if iType.Kind() == reflect.Pointer && valueOfi.IsNil() && valueOfi.IsZero() {
+		return vari{
+			Name:      "unknown",
+			Kind:      reflect.Ptr,
+			Signature: []string{fmt.Sprintf("%v", iType)},
+			Val:       dump(valueOfi, hideZeroValues, indentLevel),
+		}
+	}
 
 	typeKind := getKind(i)
 	typeName := getName(i)
diff --git a/vars_test.go b/vars_test.go
index dac71a0..2de0c28 100644
--- a/vars_test.go
+++ b/vars_test.go
@@ -113,6 +113,8 @@ type SomeStructWIthSlice struct {
 	MyAwesome []int
 }
 
+var zeroValuePointer *http.Request
+
 func TestBasicVariables(t *testing.T) {
 	t.Parallel()
 
@@ -153,6 +155,16 @@ func TestBasicVariables(t *testing.T) {
 }`,
 			},
 		},
+		{
+			tName:    "zero value pointer",
+			variable: zeroValuePointer,
+			expected: vari{
+				Name:      "unknown",
+				Kind:      reflect.Ptr,
+				Signature: []string{"*http.Request"},
+				Val:       `*http.Request(nil)`,
+			},
+		},
 		{
 			tName:    "function",
 			variable: ThisFunction,