From 15a6896694bcb73570a2cd0354dd9e7dfe22d817 Mon Sep 17 00:00:00 2001
From: Ananya Saxena <ananya@tracehq.com>
Date: Sat, 17 Oct 2020 12:39:01 -0400
Subject: [PATCH] Treating pointer to a slice as a slice

---
 TESTING.md               | 4 ++--
 codegen/config/binder.go | 8 ++++++++
 codegen/type.go          | 2 +-
 codegen/type.gotpl       | 9 +++++++--
 4 files changed, 18 insertions(+), 5 deletions(-)

diff --git a/TESTING.md b/TESTING.md
index ad7e63352ac..72ba06056c6 100644
--- a/TESTING.md
+++ b/TESTING.md
@@ -5,7 +5,7 @@ Testing generated code is a little tricky, heres how its currently set up.
 
 ### Testing responses from a server
 
-There is a server in `codegen/testserver` that is generated as part 
+There is a server in `codegen/testserver` that is generated as part
 of `go generate ./...`, and tests written against it.
 
 There are also a bunch of tests in against the examples, feel free to take examples from there.
@@ -15,7 +15,7 @@ There are also a bunch of tests in against the examples, feel free to take examp
 
 These tests are **really** slow, because they need to run the whole codegen step. Use them very sparingly. If you can, find a way to unit test it instead.
 
-Take a look at `codegen/input_test.go` for an example.
+Take a look at `codegen/testserver/input_test.go` for an example.
 
 ### Testing introspection
 
diff --git a/codegen/config/binder.go b/codegen/config/binder.go
index 2be7b7bdd6b..6de7ae117a3 100644
--- a/codegen/config/binder.go
+++ b/codegen/config/binder.go
@@ -217,6 +217,14 @@ func (t *TypeReference) IsSlice() bool {
 	return t.GQL.Elem != nil && isSlice
 }
 
+func (t *TypeReference) IsPtrToSlice() bool {
+	if t.IsPtr() {
+		_, isPointerToSlice := t.GO.(*types.Pointer).Elem().(*types.Slice)
+		return isPointerToSlice
+	}
+	return false
+}
+
 func (t *TypeReference) IsNamed() bool {
 	_, isSlice := t.GO.(*types.Named)
 	return isSlice
diff --git a/codegen/type.go b/codegen/type.go
index 06b370be7f2..5a059d70131 100644
--- a/codegen/type.go
+++ b/codegen/type.go
@@ -26,7 +26,7 @@ func processType(ret map[string]*config.TypeReference, ref *config.TypeReference
 	}
 	ret[key] = ref
 
-	if ref.IsSlice() {
+	if ref.IsSlice() || ref.IsPtrToSlice() {
 		processType(ret, ref.Elem())
 	}
 }
diff --git a/codegen/type.gotpl b/codegen/type.gotpl
index bd5c8435113..e71b4bb5c8c 100644
--- a/codegen/type.gotpl
+++ b/codegen/type.gotpl
@@ -4,7 +4,10 @@
 			{{- if and $type.IsNilable (not $type.GQL.NonNull) }}
 				if v == nil { return nil, nil }
 			{{- end }}
-			{{- if $type.IsSlice }}
+			{{- if $type.IsPtrToSlice }}
+				res, err := ec.{{ $type.Elem.UnmarshalFunc }}(ctx, v)
+				return &res, graphql.ErrorOnPath(ctx, err)
+			{{- else if $type.IsSlice }}
 				var vSlice []interface{}
 				if v != nil {
 					if tmp1, ok := v.([]interface{}); ok {
@@ -66,7 +69,9 @@
 
 	{{ with $type.MarshalFunc }}
 		func (ec *executionContext) {{ . }}(ctx context.Context, sel ast.SelectionSet, v {{ $type.GO | ref }}) graphql.Marshaler {
-			{{- if $type.IsSlice }}
+			{{- if $type.IsPtrToSlice }}
+				return ec.{{ $type.Elem.MarshalFunc }}(ctx, sel, *v)
+			{{- else if $type.IsSlice }}
 				{{- if not $type.GQL.NonNull }}
 					if v == nil {
 						return graphql.Null