Merge pull request 'fix: reuse existing migration pull requests' (#58) from fix/reuse-existing-migration-pr into main

Reviewed-on: #58

internal/forgejo/repo.go

@@ -419,7 +419,7 @@ func (rm *RepoManager) CreatePullRequest(repo, title, head, base string) error {
 	if err != nil {
 		return err
 	}
-	if status != http.StatusCreated && status != http.StatusUnprocessableEntity {
+	if status != http.StatusCreated && status != http.StatusUnprocessableEntity && status != http.StatusConflict {
 		return fmt.Errorf("unexpected Forgejo pull request status %d", status)
 	}
 	return nil

internal/forgejo/repo_test.go

@@ -426,6 +426,21 @@ func TestMergePullRequest(t *testing.T) {
 	}
 }
 
+func TestCreatePullRequestAcceptsExistingConflict(t *testing.T) {
+	server := httptest.NewServer(http.HandlerFunc(func(writer http.ResponseWriter, request *http.Request) {
+		if request.Method != http.MethodPost || request.URL.Path != "/api/v1/repos/owner/cluster/pulls" {
+			t.Fatalf("unexpected pull request request: %s %s", request.Method, request.URL.Path)
+		}
+		writer.WriteHeader(http.StatusConflict)
+	}))
+	defer server.Close()
+	manager := NewRepoManager(server.URL, "token", "owner", "user", "manifests", "cluster", "main", "maidn/bootstrap-test")
+	manager.HTTPClient = server.Client()
+	if err := manager.CreatePullRequest("cluster", "title", "maidn/bootstrap-test", "main"); err != nil {
+		t.Fatal(err)
+	}
+}
+
 func TestEnsurePullRequestChecksExactOpenBranchBeforeCreating(t *testing.T) {
 	requests := 0
 	server := httptest.NewServer(http.HandlerFunc(func(writer http.ResponseWriter, request *http.Request) {