Add branch (headRefName) source filter

check.go

@@ -20,7 +20,7 @@ func Check(request CheckRequest, manager Github) (CheckResponse, error) {
 		filterStates = request.Source.States
 	}
 
-	pulls, err := manager.ListPullRequests(filterStates)
+	pulls, err := manager.ListPullRequests(filterStates, request.Source.Branch)
 	if err != nil {
 		return nil, fmt.Errorf("failed to get last commits: %s", err)
 	}

check_test.go

@@ -262,6 +262,21 @@ func TestCheck(t *testing.T) {
 				resource.NewVersion(testPullRequests[10]),
 			},
 		},
+
+		{
+			description: "check filters out versions from a PR which do not match the branch filter",
+			source: resource.Source{
+				Repository:  "itsdalmo/test-repository",
+				AccessToken: "oauthtoken",
+				Branch:      "pr3",
+			},
+			version:      resource.Version{},
+			pullRequests: testPullRequests,
+			files:        [][]string{},
+			expected: resource.CheckResponse{
+				resource.NewVersion(testPullRequests[2]),
+			},
+		},
 	}
 
 	for _, tc := range tests {
@@ -274,10 +289,14 @@ func TestCheck(t *testing.T) {
 			}
 			for i := range tc.pullRequests {
 				for j := range filterStates {
-					if filterStates[j] == tc.pullRequests[i].PullRequestObject.State {
-						pullRequests = append(pullRequests, tc.pullRequests[i])
-						break
+					if filterStates[j] != tc.pullRequests[i].PullRequestObject.State {
+						continue
+					}
+					if tc.source.Branch != "" && tc.source.Branch != tc.pullRequests[i].PullRequestObject.HeadRefName {
+						continue
 					}
+					pullRequests = append(pullRequests, tc.pullRequests[i])
+					break
 				}
 			}
 			github.ListPullRequestsReturns(pullRequests, nil)

e2e/e2e_test.go

@@ -90,6 +90,19 @@ func TestCheckE2E(t *testing.T) {
 			},
 		},
 
+		{
+			description: "check will only return versions that match the specified branch",
+			source: resource.Source{
+				Repository:  "itsdalmo/test-repository",
+				AccessToken: os.Getenv("GITHUB_ACCESS_TOKEN"),
+				Branch:      "my_second_pull",
+			},
+			version: resource.Version{},
+			expected: resource.CheckResponse{
+				resource.Version{PR: targetPullRequestID, Commit: targetCommitID, CommittedDate: targetDateTime},
+			},
+		},
+
 		{
 			description: "check will skip versions which only match the ignore paths",
 			source: resource.Source{

github.go

@@ -20,7 +20,7 @@ import (
 // Github for testing purposes.
 //go:generate go run github.com/maxbrunsfeld/counterfeiter/v6 -o fakes/fake_github.go . Github
 type Github interface {
-	ListPullRequests([]githubv4.PullRequestState) ([]*PullRequest, error)
+	ListPullRequests([]githubv4.PullRequestState, string) ([]*PullRequest, error)
 	ListModifiedFiles(int) ([]string, error)
 	PostComment(string, string) error
 	GetPullRequest(string, string) (*PullRequest, error)
@@ -98,7 +98,7 @@ func NewGithubClient(s *Source) (*GithubClient, error) {
 }
 
 // ListPullRequests gets the last commit on all pull requests with the matching state.
-func (m *GithubClient) ListPullRequests(prStates []githubv4.PullRequestState) ([]*PullRequest, error) {
+func (m *GithubClient) ListPullRequests(prStates []githubv4.PullRequestState, prHeadRefName string) ([]*PullRequest, error) {
 	var query struct {
 		Repository struct {
 			PullRequests struct {
@@ -128,7 +128,7 @@ func (m *GithubClient) ListPullRequests(prStates []githubv4.PullRequestState) ([
 					EndCursor   githubv4.String
 					HasNextPage bool
 				}
-			} `graphql:"pullRequests(first:$prFirst,states:$prStates,after:$prCursor)"`
+			} `graphql:"pullRequests(first:$prFirst,states:$prStates,after:$prCursor,headRefName:$prHeadRefName)"`
 		} `graphql:"repository(owner:$repositoryOwner,name:$repositoryName)"`
 	}
 
@@ -137,12 +137,17 @@ func (m *GithubClient) ListPullRequests(prStates []githubv4.PullRequestState) ([
 		"repositoryName":  githubv4.String(m.Repository),
 		"prFirst":         githubv4.Int(100),
 		"prStates":        prStates,
+		"prHeadRefName":   (*githubv4.String)(nil),
 		"prCursor":        (*githubv4.String)(nil),
 		"commitsLast":     githubv4.Int(1),
 		"prReviewStates":  []githubv4.PullRequestReviewState{githubv4.PullRequestReviewStateApproved},
 		"labelsFirst":     githubv4.Int(100),
 	}
 
+	if len(prHeadRefName) > 0 {
+		vars["prHeadRefName"] = githubv4.String(prHeadRefName)
+	}
+
 	var response []*PullRequest
 	for {
 		if err := m.V4.Query(context.TODO(), &query, vars); err != nil {

models.go

@@ -27,6 +27,7 @@ type Source struct {
 	RequiredReviewApprovals int                         `json:"required_review_approvals"`
 	Labels                  []string                    `json:"labels"`
 	States                  []githubv4.PullRequestState `json:"states"`
+	Branch                  string                      `json:"branch"`
 }
 
 // Validate the source configuration.