[MODERATION] Block adding collaborators

- Ensure that the doer and blocked user cannot add each other as
collaborators to repositories.
- The Web UI gets an detailed message of the specific situation, the API
gets an generic Forbidden code.
- Unit tests has been added.
- Integration testing for Web and API has been added.
- This commit doesn't introduce removing each other as collaborators on
the block action, due to the complexity of database calls that needs to
be figured out. That deserves its own commit and test code.

modules/repository/collaborator.go

@@ -14,6 +14,10 @@ import (
 )
 
 func AddCollaborator(ctx context.Context, repo *repo_model.Repository, u *user_model.User) error {
+	if user_model.IsBlocked(ctx, repo.OwnerID, u.ID) || user_model.IsBlocked(ctx, u.ID, repo.OwnerID) {
+		return user_model.ErrBlockedByUser
+	}
+
 	return db.WithTx(ctx, func(ctx context.Context) error {
 		collaboration := &repo_model.Collaboration{
 			RepoID: repo.ID,

modules/repository/collaborator_test.go

@@ -33,6 +33,33 @@ func TestRepository_AddCollaborator(t *testing.T) {
 	testSuccess(3, 4)
 }
 
+func TestRepository_AddCollaborator_IsBlocked(t *testing.T) {
+	assert.NoError(t, unittest.PrepareTestDatabase())
+
+	testSuccess := func(repoID, userID int64) {
+		repo := unittest.AssertExistsAndLoadBean(t, &repo_model.Repository{ID: repoID})
+		assert.NoError(t, repo.LoadOwner(db.DefaultContext))
+		user := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: userID})
+
+		// Owner blocked user.
+		unittest.AssertSuccessfulInsert(t, &user_model.BlockedUser{UserID: repo.OwnerID, BlockID: userID})
+		assert.ErrorIs(t, AddCollaborator(db.DefaultContext, repo, user), user_model.ErrBlockedByUser)
+		unittest.CheckConsistencyFor(t, &repo_model.Repository{ID: repoID}, &user_model.User{ID: userID})
+		_, err := db.DeleteByBean(db.DefaultContext, &user_model.BlockedUser{UserID: repo.OwnerID, BlockID: userID})
+		assert.NoError(t, err)
+
+		// User has owner blocked.
+		unittest.AssertSuccessfulInsert(t, &user_model.BlockedUser{UserID: userID, BlockID: repo.OwnerID})
+		assert.ErrorIs(t, AddCollaborator(db.DefaultContext, repo, user), user_model.ErrBlockedByUser)
+		unittest.CheckConsistencyFor(t, &repo_model.Repository{ID: repoID}, &user_model.User{ID: userID})
+	}
+	// Ensure idempotency (public repository).
+	testSuccess(1, 4)
+	testSuccess(1, 4)
+	// Add collaborator to private repository.
+	testSuccess(3, 4)
+}
+
 func TestRepoPermissionPublicNonOrgRepo(t *testing.T) {
 	assert.NoError(t, unittest.PrepareTestDatabase())
 

options/locale/locale_en-US.ini

@@ -607,6 +607,7 @@ block_user = Block User
 block_user.detail = Please understand that if you block this user, other actions will be taken. Such as:
 block_user.detail_1 = You are being unfollowed from this user.
 block_user.detail_2 = This user cannot interact with your repositories, created issues and comments.
+block_user.detail_3 = This user cannot add you as a collaborator, nor can you add them as a collaborator.
 follow_blocked_user = You cannot follow this user because you have blocked this user or this user has blocked you.
 
 form.name_reserved = The username "%s" is reserved.
@@ -2080,6 +2081,8 @@ settings.add_collaborator_success = The collaborator has been added.
 settings.add_collaborator_inactive_user = Cannot add an inactive user as a collaborator.
 settings.add_collaborator_owner = Cannot add an owner as a collaborator.
 settings.add_collaborator_duplicate = The collaborator is already added to this repository.
+settings.add_collaborator_blocked_our = Cannot add the collaborator, because the repository owner has blocked them.
+settings.add_collaborator_blocked_them = Cannot add the collaborator, because they have blocked the repository owner.
 settings.delete_collaborator = Remove
 settings.collaborator_deletion = Remove Collaborator
 settings.collaborator_deletion_desc = Removing a collaborator will revoke their access to this repository. Continue?

routers/api/v1/repo/collaborators.go

@@ -156,6 +156,8 @@ func AddCollaborator(ctx *context.APIContext) {
 	//     "$ref": "#/responses/empty"
 	//   "422":
 	//     "$ref": "#/responses/validationError"
+	//   "403":
+	//     "$ref": "#/responses/forbidden"
 
 	form := web.GetForm(ctx).(*api.AddCollaboratorOption)
 
@@ -175,7 +177,11 @@ func AddCollaborator(ctx *context.APIContext) {
 	}
 
 	if err := repo_module.AddCollaborator(ctx, ctx.Repo.Repository, collaborator); err != nil {
-		ctx.Error(http.StatusInternalServerError, "AddCollaborator", err)
+		if errors.Is(err, user_model.ErrBlockedByUser) {
+			ctx.Error(http.StatusForbidden, "AddCollaborator", err)
+		} else {
+			ctx.Error(http.StatusInternalServerError, "AddCollaborator", err)
+		}
 		return
 	}
 

routers/web/repo/setting/collaboration.go

@@ -4,6 +4,7 @@
 package setting
 
 import (
+	"errors"
 	"net/http"
 	"strings"
 
@@ -102,7 +103,18 @@ func CollaborationPost(ctx *context.Context) {
 	}
 
 	if err = repo_module.AddCollaborator(ctx, ctx.Repo.Repository, u); err != nil {
-		ctx.ServerError("AddCollaborator", err)
+		if !errors.Is(err, user_model.ErrBlockedByUser) {
+			ctx.ServerError("AddCollaborator", err)
+			return
+		}
+
+		// To give an good error message, be precise on who has blocked who.
+		if blockedOurs := user_model.IsBlocked(ctx, ctx.Repo.Repository.OwnerID, u.ID); blockedOurs {
+			ctx.Flash.Error(ctx.Tr("repo.settings.add_collaborator_blocked_our"))
+		} else {
+			ctx.Flash.Error(ctx.Tr("repo.settings.add_collaborator_blocked_them"))
+		}
+		ctx.Redirect(ctx.Repo.RepoLink + "/settings/collaboration")
 		return
 	}
 

routers/web/repo/setting/settings_test.go

@@ -102,13 +102,15 @@ func TestCollaborationPost(t *testing.T) {
 	ctx.Req.Form.Set("collaborator", "user4")
 
 	u := &user_model.User{
+		ID:        2,
 		LowerName: "user2",
 		Type:      user_model.UserTypeIndividual,
 	}
 
 	re := &repo_model.Repository{
-		ID:    2,
+		ID:      2,
-		Owner: u,
+		Owner:   u,
+		OwnerID: u.ID,
 	}
 
 	repo := &context.Repository{
@@ -160,13 +162,15 @@ func TestCollaborationPost_AddCollaboratorTwice(t *testing.T) {
 	ctx.Req.Form.Set("collaborator", "user4")
 
 	u := &user_model.User{
+		ID:        2,
 		LowerName: "user2",
 		Type:      user_model.UserTypeIndividual,
 	}
 
 	re := &repo_model.Repository{
-		ID:    2,
+		ID:      2,
-		Owner: u,
+		Owner:   u,
+		OwnerID: u.ID,
 	}
 
 	repo := &context.Repository{

templates/swagger/v1_json.tmpl

@@ -3948,6 +3948,9 @@
           "204": {
             "$ref": "#/responses/empty"
           },
+          "403": {
+            "$ref": "#/responses/forbidden"
+          },
           "422": {
             "$ref": "#/responses/validationError"
           }

templates/user/profile.tmpl

@@ -52,6 +52,7 @@
 		<ul>
 				<li>{{$.locale.Tr "user.block_user.detail_1"}}</li>
 				<li>{{$.locale.Tr "user.block_user.detail_2"}}</li>
+				<li>{{$.locale.Tr "user.block_user.detail_3"}}</li>
 		</ul>
 	</div>
 	{{template "base/modal_actions_confirm" .}}

tests/integration/api_block_test.go

@@ -9,6 +9,7 @@ import (
 	"testing"
 
 	auth_model "code.gitea.io/gitea/models/auth"
+	repo_model "code.gitea.io/gitea/models/repo"
 	"code.gitea.io/gitea/models/unittest"
 	user_model "code.gitea.io/gitea/models/user"
 	api "code.gitea.io/gitea/modules/structs"
@@ -99,3 +100,42 @@ func TestAPIOrgBlock(t *testing.T) {
 		unittest.AssertNotExistsBean(t, &user_model.BlockedUser{UserID: 6, BlockID: 2})
 	})
 }
+
+// TestAPIBlock_AddCollaborator ensures that the doer and blocked user cannot
+// add each others as collaborators via the API.
+func TestAPIBlock_AddCollaborator(t *testing.T) {
+	defer tests.PrepareTestEnv(t)()
+
+	user1 := "user10"
+	user2 := "user2"
+	perm := "write"
+	collabOption := &api.AddCollaboratorOption{Permission: &perm}
+
+	// User1 blocks User2.
+	session := loginUser(t, user1)
+	token := getTokenForLoggedInUser(t, session, auth_model.AccessTokenScopeWriteUser, auth_model.AccessTokenScopeWriteRepository)
+
+	req := NewRequest(t, "PUT", fmt.Sprintf("/api/v1/user/block/%s?token=%s", user2, token))
+	MakeRequest(t, req, http.StatusNoContent)
+	unittest.AssertExistsAndLoadBean(t, &user_model.BlockedUser{UserID: 10, BlockID: 2})
+
+	t.Run("BlockedUser Add Doer", func(t *testing.T) {
+		defer tests.PrintCurrentTest(t)()
+		repo := unittest.AssertExistsAndLoadBean(t, &repo_model.Repository{ID: 2, OwnerID: 2})
+		session := loginUser(t, user2)
+		token := getTokenForLoggedInUser(t, session, auth_model.AccessTokenScopeWriteRepository)
+
+		req := NewRequestWithJSON(t, "PUT", fmt.Sprintf("/api/v1/repos/%s/%s/collaborators/%s?token=%s", user2, repo.Name, user1, token), collabOption)
+		session.MakeRequest(t, req, http.StatusForbidden)
+	})
+
+	t.Run("Doer Add BlockedUser", func(t *testing.T) {
+		defer tests.PrintCurrentTest(t)()
+		repo := unittest.AssertExistsAndLoadBean(t, &repo_model.Repository{ID: 7, OwnerID: 10})
+		session := loginUser(t, user1)
+		token := getTokenForLoggedInUser(t, session, auth_model.AccessTokenScopeWriteRepository)
+
+		req := NewRequestWithJSON(t, "PUT", fmt.Sprintf("/api/v1/repos/%s/%s/collaborators/%s?token=%s", user1, repo.Name, user2, token), collabOption)
+		session.MakeRequest(t, req, http.StatusForbidden)
+	})
+}

tests/integration/block_test.go

@@ -16,6 +16,7 @@ import (
 	repo_model "code.gitea.io/gitea/models/repo"
 	"code.gitea.io/gitea/models/unittest"
 	user_model "code.gitea.io/gitea/models/user"
+	forgejo_context "code.gitea.io/gitea/modules/context"
 	"code.gitea.io/gitea/modules/translation"
 	"code.gitea.io/gitea/tests"
 
@@ -210,3 +211,47 @@ func TestBlockUserFromOrganization(t *testing.T) {
 	session.MakeRequest(t, req, http.StatusSeeOther)
 	unittest.AssertNotExistsBean(t, &user_model.BlockedUser{BlockID: blockedUser.ID, UserID: org.ID})
 }
+
+// TestBlockAddCollaborator ensures that the doer and blocked user cannot add each each other as collaborators.
+func TestBlockAddCollaborator(t *testing.T) {
+	defer tests.PrepareTestEnv(t)()
+
+	user1 := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 10})
+	user2 := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 2})
+
+	BlockUser(t, user1, user2)
+
+	t.Run("BlockedUser Add Doer", func(t *testing.T) {
+		defer tests.PrintCurrentTest(t)()
+
+		repo := unittest.AssertExistsAndLoadBean(t, &repo_model.Repository{ID: 2, OwnerID: user2.ID})
+
+		session := loginUser(t, user2.Name)
+		req := NewRequestWithValues(t, "POST", path.Join(repo.Link(), "/settings/collaboration"), map[string]string{
+			"_csrf":        GetCSRF(t, session, path.Join(repo.Link(), "/settings/collaboration")),
+			"collaborator": user1.Name,
+		})
+		session.MakeRequest(t, req, http.StatusSeeOther)
+
+		flashCookie := session.GetCookie(forgejo_context.CookieNameFlash)
+		assert.NotNil(t, flashCookie)
+		assert.EqualValues(t, "error%3DCannot%2Badd%2Bthe%2Bcollaborator%252C%2Bbecause%2Bthey%2Bhave%2Bblocked%2Bthe%2Brepository%2Bowner.", flashCookie.Value)
+	})
+
+	t.Run("Doer Add BlockedUser", func(t *testing.T) {
+		defer tests.PrintCurrentTest(t)()
+
+		repo := unittest.AssertExistsAndLoadBean(t, &repo_model.Repository{ID: 7, OwnerID: user1.ID})
+
+		session := loginUser(t, user1.Name)
+		req := NewRequestWithValues(t, "POST", path.Join(repo.Link(), "/settings/collaboration"), map[string]string{
+			"_csrf":        GetCSRF(t, session, path.Join(repo.Link(), "/settings/collaboration")),
+			"collaborator": user2.Name,
+		})
+		session.MakeRequest(t, req, http.StatusSeeOther)
+
+		flashCookie := session.GetCookie(forgejo_context.CookieNameFlash)
+		assert.NotNil(t, flashCookie)
+		assert.EqualValues(t, "error%3DCannot%2Badd%2Bthe%2Bcollaborator%252C%2Bbecause%2Bthe%2Brepository%2Bowner%2Bhas%2Bblocked%2Bthem.", flashCookie.Value)
+	})
+}