From a575dcc9401bdad3ece02d301b8d9f90975d1159 Mon Sep 17 00:00:00 2001
From: Rein Krul <info@reinkrul.nl>
Date: Tue, 28 Nov 2023 07:19:03 +0100
Subject: [PATCH] PEX: ldp_vp with 1 VC should not index credential property

---
 vcr/pe/presentation_submission.go      | 10 +++++++
 vcr/pe/presentation_submission_test.go | 37 +++++++++++++++++++++++---
 vcr/pe/test/test_definitions.go        |  2 ++
 3 files changed, 46 insertions(+), 3 deletions(-)

diff --git a/vcr/pe/presentation_submission.go b/vcr/pe/presentation_submission.go
index fdd1bf6cdc..3ced0e08fa 100644
--- a/vcr/pe/presentation_submission.go
+++ b/vcr/pe/presentation_submission.go
@@ -147,6 +147,16 @@ func (b *PresentationSubmissionBuilder) Build(format string) (PresentationSubmis
 		}
 	}
 
+	// the verifiableCredential property in Verifiable Presentations can be a single VC or an array of VCs when represented in JSON.
+	// go-did always marshals a single VC as a single VC for JSON-LD VPs. So we might need to fix the mapping paths.
+	if format == vc.JSONLDPresentationProofFormat {
+		for _, signInstruction := range nonEmptySignInstructions {
+			if len(signInstruction.Mappings) == 1 {
+				signInstruction.Mappings[0].Path = "$.verifiableCredential"
+			}
+		}
+	}
+
 	index := 0
 	// last we create the descriptor map for the presentation submission
 	// If there's only one sign instruction the Path will be $.
diff --git a/vcr/pe/presentation_submission_test.go b/vcr/pe/presentation_submission_test.go
index 8724e2b0ee..23e8a42462 100644
--- a/vcr/pe/presentation_submission_test.go
+++ b/vcr/pe/presentation_submission_test.go
@@ -53,7 +53,38 @@ func TestPresentationSubmissionBuilder_Build(t *testing.T) {
 	vc2 := credentialToJSONLD(vc.VerifiableCredential{ID: &id2})
 	vc3 := credentialToJSONLD(vc.VerifiableCredential{ID: &id3})
 
-	t.Run("1 presentation", func(t *testing.T) {
+	t.Run("1 presentation with 1 credential", func(t *testing.T) {
+		expectedJSON := `
+		{
+		 "id": "for-test",
+		 "definition_id": "",
+		 "descriptor_map": [
+		   {
+		     "format": "ldp_vc",
+		     "id": "Match ID=1",
+		     "path": "$.verifiableCredential"
+		   }
+		 ]
+		}`
+		presentationDefinition := PresentationDefinition{}
+		_ = json.Unmarshal([]byte(test.PickOne), &presentationDefinition)
+		builder := presentationDefinition.PresentationSubmissionBuilder()
+		builder.AddWallet(holder1, []vc.VerifiableCredential{vc1, vc2})
+
+		submission, signInstructions, err := builder.Build("ldp_vp")
+
+		require.NoError(t, err)
+		require.NotNil(t, signInstructions)
+		assert.Len(t, signInstructions, 1)
+		require.Len(t, submission.DescriptorMap, 1)
+		assert.Equal(t, "$.verifiableCredential", submission.DescriptorMap[0].Path)
+
+		submission.Id = "for-test" // easier assertion
+		actualJSON, _ := json.MarshalIndent(submission, "", "  ")
+		println(string(actualJSON))
+		assert.JSONEq(t, expectedJSON, string(actualJSON))
+	})
+	t.Run("1 presentation with 2 credentials", func(t *testing.T) {
 		expectedJSON := `
 		{
 		 "id": "for-test",
@@ -101,7 +132,7 @@ func TestPresentationSubmissionBuilder_Build(t *testing.T) {
       "path_nested": {
         "format": "ldp_vc",
         "id": "Match ID=1",
-        "path": "$.verifiableCredential[0]"
+        "path": "$.verifiableCredential"
       }
     },
     {
@@ -111,7 +142,7 @@ func TestPresentationSubmissionBuilder_Build(t *testing.T) {
       "path_nested": {
         "format": "ldp_vc",
         "id": "Match ID=2",
-        "path": "$.verifiableCredential[0]"
+        "path": "$.verifiableCredential"
       }
     }
   ]
diff --git a/vcr/pe/test/test_definitions.go b/vcr/pe/test/test_definitions.go
index 3562eebb96..587a3d9e54 100644
--- a/vcr/pe/test/test_definitions.go
+++ b/vcr/pe/test/test_definitions.go
@@ -30,6 +30,7 @@ const PickOne = `
   ],
   "input_descriptors": [
 	{
+      "id": "Match ID=1",
 	  "name": "Pick 1",
       "group": ["A"],
 	  "constraints": {
@@ -47,6 +48,7 @@ const PickOne = `
 	  }
     },
     {
+      "id": "Match ID=2",
 	  "name": "Pick 2",
       "group": ["A"],
 	  "constraints": {