Return nil instead of 404 error if branch does not exist (#806)

Author: threeseed

github/data_source_github_branch.go

@@ -2,9 +2,10 @@ package github
 
 import (
 	"context"
-	"fmt"
 	"log"
+	"net/http"
 
+	"github.com/google/go-github/v35/github"
 	"github.com/hashicorp/terraform-plugin-sdk/helper/schema"
 )
 
@@ -46,13 +47,17 @@ func dataSourceGithubBranchRead(d *schema.ResourceData, meta interface{}) error
 	branchName := d.Get("branch").(string)
 	branchRefName := "refs/heads/" + branchName
 
-	log.Printf("[DEBUG] Reading GitHub branch reference %s/%s (%s)",
-		orgName, repoName, branchRefName)
-	ref, resp, err := client.Git.GetRef(
-		context.TODO(), orgName, repoName, branchRefName)
+	log.Printf("[DEBUG] Reading GitHub branch reference %s/%s (%s)", orgName, repoName, branchRefName)
+	ref, resp, err := client.Git.GetRef(context.TODO(), orgName, repoName, branchRefName)
 	if err != nil {
-		return fmt.Errorf("Error reading GitHub branch reference %s/%s (%s): %s",
-			orgName, repoName, branchRefName, err)
+		if err, ok := err.(*github.ErrorResponse); ok {
+			if err.Response.StatusCode == http.StatusNotFound {
+				log.Printf("Error reading GitHub branch reference %s/%s (%s): %s", orgName, repoName, branchRefName, err)
+				d.SetId("")
+				return nil
+			}
+		}
+		return err
 	}
 
 	d.SetId(buildTwoPartID(repoName, branchName))

github/data_source_github_branch_test.go

@@ -59,4 +59,51 @@ func TestAccGithubBranchDataSource(t *testing.T) {
 		})
 
 	})
+
+	t.Run("queries an invalid branch without error", func(t *testing.T) {
+
+		config := fmt.Sprintf(`
+			resource "github_repository" "test" {
+			  name = "tf-acc-test-%[1]s"
+				auto_init = true
+			}
+
+			data "github_branch" "test" {
+				repository = github_repository.test.id
+				branch = "xxxxxx"
+			}
+		`, randomID)
+
+		check := resource.ComposeTestCheckFunc(
+			resource.TestCheckNoResourceAttr(
+				"data.github_branch.test", "id",
+			),
+		)
+
+		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) {
+			t.Skip("anonymous account not supported for this operation")
+		})
+
+		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)
+		})
+
+	})
 }