From 182faef042b2ce1cb0dc1120748ec8fd472f04a4 Mon Sep 17 00:00:00 2001
From: Alex Dancho <alex.dancho@newsela.com>
Date: Sun, 13 Feb 2022 16:24:22 -0500
Subject: [PATCH] Allow for retrieving latest prerelease as data source.

---
 github/data_source_github_release.go      | 33 ++++++++++++++++-
 github/data_source_github_release_test.go | 44 +++++++++++++++++++++++
 github/provider_utils.go                  |  3 ++
 3 files changed, 79 insertions(+), 1 deletion(-)

diff --git a/github/data_source_github_release.go b/github/data_source_github_release.go
index 08f790b3ea..97b8db9322 100644
--- a/github/data_source_github_release.go
+++ b/github/data_source_github_release.go
@@ -30,6 +30,7 @@ func dataSourceGithubRelease() *schema.Resource {
 				Type:     schema.TypeString,
 				Required: true,
 				ValidateFunc: validation.StringInSlice([]string{
+					"latest_prerelease",
 					"latest",
 					"id",
 					"tag",
@@ -108,8 +109,38 @@ func dataSourceGithubReleaseRead(d *schema.ResourceData, meta interface{}) error
 
 	var err error
 	var release *github.RepositoryRelease
-
 	switch retrieveBy := strings.ToLower(d.Get("retrieve_by").(string)); retrieveBy {
+	case "latest_prerelease":
+		// The GitHub API doesn't specify a way to just load the most recent prerelease,
+		// so we'll load all releases and determine which one is the most recent
+		// prerelease after.
+		log.Printf("[INFO] Refreshing GitHub latest prerelease from repository %s", repository)
+		var releases []*github.RepositoryRelease
+		nextPage := 1
+		// TODO: 10 is sort of arbitrary here -- what's the best way to allow configurability
+		// for this to prevent the provider from becoming glacially slow on large repos?
+		for nextPage < 10 {
+			opt := &github.ListOptions{Page: nextPage}
+			var response *github.Response
+			releases, response, err = client.Repositories.ListReleases(ctx, owner, repository, opt)
+			for _, rel := range releases {
+				if *rel.Prerelease != true || *rel.Draft == true {
+					continue
+				}
+				if release == nil {
+					release = rel
+				} else {
+					if rel.PublishedAt.After(release.PublishedAt.Time) {
+						release = rel
+					}
+				}
+			}
+			if response.NextPage > nextPage {
+				nextPage = response.NextPage
+			} else {
+				break
+			}
+		}
 	case "latest":
 		log.Printf("[INFO] Refreshing GitHub latest release from repository %s", repository)
 		release, _, err = client.Repositories.GetLatestRelease(ctx, owner, repository)
diff --git a/github/data_source_github_release_test.go b/github/data_source_github_release_test.go
index eae10c0f0a..5179684228 100644
--- a/github/data_source_github_release_test.go
+++ b/github/data_source_github_release_test.go
@@ -13,6 +13,7 @@ func TestAccGithubReleaseDataSource(t *testing.T) {
 
 	testReleaseRepository := os.Getenv("GITHUB_TEMPLATE_REPOSITORY")
 	testReleaseID := os.Getenv("GITHUB_TEMPLATE_REPOSITORY_RELEASE_ID")
+	testPrereleaseID := os.Getenv("GITHUB_TEMPLATE_REPOSITORY_PRERELEASE_ID")
 	testReleaseOwner := testOrganizationFunc()
 
 	t.Run("queries latest release", func(t *testing.T) {
@@ -58,6 +59,49 @@ func TestAccGithubReleaseDataSource(t *testing.T) {
 
 	})
 
+	t.Run("queries latest prerelease", func(t *testing.T) {
+
+		config := fmt.Sprintf(`
+			data "github_release" "test" {
+				repository = "%s"
+				owner = "%s"
+				retrieve_by = "latest_prerelease"
+			}
+		`, testReleaseRepository, testReleaseOwner)
+
+		check := resource.ComposeTestCheckFunc(
+			resource.TestCheckResourceAttr(
+				"data.github_release.test", "id", testPrereleaseID,
+			),
+		)
+
+		testCase := func(t *testing.T, mode string) {
+			resource.Test(t, resource.TestCase{
+				PreCheck:  func() { skipUnlessMode(t, mode) },
+				Providers: testAccProviders,
+				Steps: []resource.TestStep{
+					{
+						Config: config,
+						Check:  check,
+					},
+				},
+			})
+		}
+
+		t.Run("with an anonymous account", func(t *testing.T) {
+			testCase(t, anonymous)
+		})
+
+		t.Run("with an individual account", func(t *testing.T) {
+			testCase(t, individual)
+		})
+
+		t.Run("with an organization account", func(t *testing.T) {
+			testCase(t, organization)
+		})
+
+	})
+
 	t.Run("queries release by ID or tag", func(t *testing.T) {
 
 		config := fmt.Sprintf(`
diff --git a/github/provider_utils.go b/github/provider_utils.go
index 3672c7508d..b79e46570a 100644
--- a/github/provider_utils.go
+++ b/github/provider_utils.go
@@ -33,6 +33,9 @@ func testAccPreCheck(t *testing.T) {
 	if v := os.Getenv("GITHUB_TEMPLATE_REPOSITORY_RELEASE_ID"); v == "" {
 		t.Fatal("GITHUB_TEMPLATE_REPOSITORY_RELEASE_ID must be set for acceptance tests")
 	}
+	if v := os.Getenv("GITHUB_TEMPLATE_REPOSITORY_PRERELEASE_ID"); v == "" {
+		t.Fatal("GITHUB_TEMPLATE_REPOSITORY_PRERELEASE_ID must be set for acceptance tests")
+	}
 }
 
 func skipUnlessMode(t *testing.T, providerMode string) {