From 55c8aefd55a5c385ded8f271c6e1a8b86566d68b Mon Sep 17 00:00:00 2001
From: Doug Simmons <doug@mach6.net>
Date: Mon, 17 Aug 2020 16:46:22 -0700
Subject: [PATCH] Do not ignore paginated reponse from github PR Listfiles API

Fix issue where only the first page (30 files max) was considered
---
 plugin/scm_clients/github_client.go      | 25 ++++++++-----
 plugin/scm_clients/github_client_test.go | 45 ++++++++++++++++++++++--
 2 files changed, 59 insertions(+), 11 deletions(-)

diff --git a/plugin/scm_clients/github_client.go b/plugin/scm_clients/github_client.go
index 948eadd..bcad2f4 100644
--- a/plugin/scm_clients/github_client.go
+++ b/plugin/scm_clients/github_client.go
@@ -3,6 +3,7 @@ package scm_clients
 import (
 	"context"
 	"fmt"
+
 	"github.com/drone/drone-go/drone"
 	"github.com/google/go-github/github"
 	"github.com/google/uuid"
@@ -38,13 +39,22 @@ func NewGitHubClient(ctx context.Context, uuid uuid.UUID, server string, token s
 
 func (s GithubClient) ChangedFilesInPullRequest(ctx context.Context, pullRequestID int) ([]string, error) {
 	var changedFiles []string
-	files, _, err := s.listFiles(ctx, pullRequestID)
-	if err != nil {
-		return nil, err
-	}
-	for _, file := range files {
-		changedFiles = append(changedFiles, *file.Filename)
+	opts := &github.ListOptions{}
+
+	for {
+		files, resp, err := s.listFiles(ctx, pullRequestID, opts)
+		if err != nil {
+			return nil, err
+		}
+		for _, file := range files {
+			changedFiles = append(changedFiles, *file.Filename)
+		}
+		if resp.NextPage == 0 {
+			break
+		}
+		opts.Page = resp.NextPage
 	}
+
 	return changedFiles, nil
 }
 
@@ -91,9 +101,8 @@ func (s GithubClient) GetFileListing(ctx context.Context, path string, commitRef
 	return result, err
 }
 
-func (s GithubClient) listFiles(ctx context.Context, number int) (
+func (s GithubClient) listFiles(ctx context.Context, number int, opts *github.ListOptions) (
 	[]*github.CommitFile, *github.Response, error) {
-	opts := &github.ListOptions{}
 	return s.delegate.PullRequests.ListFiles(ctx, s.repo.Namespace, s.repo.Name, number, opts)
 }
 
diff --git a/plugin/scm_clients/github_client_test.go b/plugin/scm_clients/github_client_test.go
index 97d3b37..65987ac 100644
--- a/plugin/scm_clients/github_client_test.go
+++ b/plugin/scm_clients/github_client_test.go
@@ -1,14 +1,17 @@
 package scm_clients
 
 import (
-	"github.com/drone/drone-go/drone"
-	"github.com/google/uuid"
-	"github.com/sirupsen/logrus"
+	"fmt"
 	"io"
 	"net/http"
 	"net/http/httptest"
 	"os"
+	"reflect"
 	"testing"
+
+	"github.com/drone/drone-go/drone"
+	"github.com/google/uuid"
+	"github.com/sirupsen/logrus"
 )
 
 const mockGithubToken = "7535706b694c63526c6e4f5230374243"
@@ -47,6 +50,31 @@ func TestGithubClient_ChangedFilesInPullRequest(t *testing.T) {
 	BaseTest_ChangedFilesInPullRequest(t, client)
 }
 
+func TestGithubClient_ChangedFilesInPullRequest_Paginated(t *testing.T) {
+	ts := httptest.NewServer(testMuxGithub())
+	defer ts.Close()
+	client, err := createGithubClient(ts.URL)
+	if err != nil {
+		t.Error(err)
+		return
+	}
+
+	actualFiles, err := client.ChangedFilesInPullRequest(noContext, 4)
+	if err != nil {
+		t.Error(err)
+		return
+	}
+
+	expectedFiles := []string{
+		"e/f/g/h/.drone.yml",
+		"e/f/g/h/.drone.yml",
+	}
+
+	if want, got := expectedFiles, actualFiles; !reflect.DeepEqual(want, got) {
+		t.Errorf("Test failed:\n  want %q\n   got %q", want, got)
+	}
+}
+
 func TestGithubClient_GetFileListing(t *testing.T) {
 	ts := httptest.NewServer(testMuxGithub())
 	defer ts.Close()
@@ -96,6 +124,17 @@ func testMuxGithub() *http.ServeMux {
 			f, _ := os.Open("../testdata/github/pull_3_files.json")
 			_, _ = io.Copy(w, f)
 		})
+	mux.HandleFunc("/repos/foosinn/dronetest/pulls/4/files",
+		func(w http.ResponseWriter, r *http.Request) {
+			// simulate a paginated response
+			if r.FormValue("page") == "" {
+				next := fmt.Sprintf("<%s?page=2>; rel=\"next\"", r.URL.String())
+				last := fmt.Sprintf("<%s?page=2>; rel=\"last\"", r.URL.String())
+				w.Header().Add("Link", fmt.Sprintf("%s, %s", next, last))
+			}
+			f, _ := os.Open("../testdata/github/pull_3_files.json")
+			_, _ = io.Copy(w, f)
+		})
 	mux.HandleFunc("/repos/foosinn/dronetest/contents/afolder/.drone.yml",
 		func(w http.ResponseWriter, r *http.Request) {
 			f, _ := os.Open("../testdata/github/afolder_.drone.yml.json")