New webhook trigger for receiving Pull Request review requests (#24481)

close https://github.com/go-gitea/gitea/issues/16321

Provided a webhook trigger for requesting someone to review the Pull
Request.

Some modifications have been made to the returned `PullRequestPayload`
based on the GitHub webhook settings, including:
- add a description of the current reviewer object as
`RequestedReviewer` .
- setting the action to either **review_requested** or
**review_request_removed** based on the operation.
- adding the `RequestedReviewers` field to the issues_model.PullRequest.
This field will be loaded into the PullRequest through
`LoadRequestedReviewers()` when `ToAPIPullRequest` is called.

After the Pull Request is merged, I will supplement the relevant
documentation.

7 files changed, 130 insertions, 9 deletions

diff --git a/models/issues/pull.go b/models/issues/pull.go
index 218a265741..3f37d8d243 100644
--- a/models/issues/pull.go
+++ b/models/issues/pull.go
@@ -175,9 +175,10 @@ type PullRequest struct {
 
 	ChangedProtectedFiles []string `xorm:"TEXT JSON"`
 
-	IssueID int64  `xorm:"INDEX"`
-	Issue   *Issue `xorm:"-"`
-	Index   int64
+	IssueID            int64  `xorm:"INDEX"`
+	Issue              *Issue `xorm:"-"`
+	Index              int64
+	RequestedReviewers []*user_model.User `xorm:"-"`
 
 	HeadRepoID          int64                  `xorm:"INDEX"`
 	HeadRepo            *repo_model.Repository `xorm:"-"`
@@ -302,6 +303,29 @@ func (pr *PullRequest) LoadHeadRepo(ctx context.Context) (err error) {
 	return nil
 }
 
+// LoadRequestedReviewers loads the requested reviewers.
+func (pr *PullRequest) LoadRequestedReviewers(ctx context.Context) error {
+	if len(pr.RequestedReviewers) > 0 {
+		return nil
+	}
+
+	reviews, err := GetReviewsByIssueID(pr.Issue.ID)
+	if err != nil {
+		return err
+	}
+
+	if len(reviews) > 0 {
+		err = LoadReviewers(ctx, reviews)
+		if err != nil {
+			return err
+		}
+		for _, review := range reviews {
+			pr.RequestedReviewers = append(pr.RequestedReviewers, review.Reviewer)
+		}
+	}
+	return nil
+}
+
 // LoadBaseRepo loads the target repository. ErrRepoNotExist may be returned.
 func (pr *PullRequest) LoadBaseRepo(ctx context.Context) (err error) {
 	if pr.BaseRepo != nil {
diff --git a/models/issues/pull_test.go b/models/issues/pull_test.go
index 0b06095213..7a183ac312 100644
--- a/models/issues/pull_test.go
+++ b/models/issues/pull_test.go
@@ -9,6 +9,7 @@ import (
 	"code.gitea.io/gitea/models/db"
 	issues_model "code.gitea.io/gitea/models/issues"
 	"code.gitea.io/gitea/models/unittest"
+	user_model "code.gitea.io/gitea/models/user"
 
 	"github.com/stretchr/testify/assert"
 )
@@ -74,6 +75,34 @@ func TestPullRequestsNewest(t *testing.T) {
 	}
 }
 
+func TestLoadRequestedReviewers(t *testing.T) {
+	assert.NoError(t, unittest.PrepareTestDatabase())
+
+	pull := unittest.AssertExistsAndLoadBean(t, &issues_model.PullRequest{ID: 1})
+	assert.NoError(t, pull.LoadIssue(db.DefaultContext))
+	issue := pull.Issue
+	assert.NoError(t, issue.LoadRepo(db.DefaultContext))
+	assert.Len(t, pull.RequestedReviewers, 0)
+
+	user1, err := user_model.GetUserByID(db.DefaultContext, 1)
+	assert.NoError(t, err)
+
+	comment, err := issues_model.AddReviewRequest(issue, user1, &user_model.User{})
+	assert.NoError(t, err)
+	assert.NotNil(t, comment)
+
+	assert.NoError(t, pull.LoadRequestedReviewers(db.DefaultContext))
+	assert.Len(t, pull.RequestedReviewers, 1)
+
+	comment, err = issues_model.RemoveReviewRequest(issue, user1, &user_model.User{})
+	assert.NoError(t, err)
+	assert.NotNil(t, comment)
+
+	pull.RequestedReviewers = nil
+	assert.NoError(t, pull.LoadRequestedReviewers(db.DefaultContext))
+	assert.Empty(t, pull.RequestedReviewers)
+}
+
 func TestPullRequestsOldest(t *testing.T) {
 	assert.NoError(t, unittest.PrepareTestDatabase())
 	prs, count, err := issues_model.PullRequests(1, &issues_model.PullRequestsOptions{
diff --git a/models/issues/review.go b/models/issues/review.go
index ed30bce149..06cf132a48 100644
--- a/models/issues/review.go
+++ b/models/issues/review.go
@@ -162,6 +162,27 @@ func (r *Review) LoadReviewer(ctx context.Context) (err error) {
 	return err
 }
 
+// LoadReviewers loads reviewers
+func LoadReviewers(ctx context.Context, reviews []*Review) (err error) {
+	reviewerIds := make([]int64, len(reviews))
+	for i := 0; i < len(reviews); i++ {
+		reviewerIds[i] = reviews[i].ReviewerID
+	}
+	reviewers, err := user_model.GetPossibleUserByIDs(ctx, reviewerIds)
+	if err != nil {
+		return err
+	}
+
+	userMap := make(map[int64]*user_model.User, len(reviewers))
+	for _, reviewer := range reviewers {
+		userMap[reviewer.ID] = reviewer
+	}
+	for _, review := range reviews {
+		review.Reviewer = userMap[review.ReviewerID]
+	}
+	return nil
+}
+
 // LoadReviewerTeam loads reviewer team
 func (r *Review) LoadReviewerTeam(ctx context.Context) (err error) {
 	if r.ReviewerTeamID == 0 || r.ReviewerTeam != nil {
@@ -520,8 +541,8 @@ func GetReviews(ctx context.Context, opts *GetReviewOptions) ([]*Review, error)
 	return reviews, sess.Find(&reviews)
 }
 
-// GetReviewersByIssueID gets the latest review of each reviewer for a pull request
-func GetReviewersByIssueID(issueID int64) ([]*Review, error) {
+// GetReviewsByIssueID gets the latest review of each reviewer for a pull request
+func GetReviewsByIssueID(issueID int64) ([]*Review, error) {
 	reviews := make([]*Review, 0, 10)
 
 	sess := db.GetEngine(db.DefaultContext)
diff --git a/models/issues/review_test.go b/models/issues/review_test.go
index 3221496577..0cb621812c 100644
--- a/models/issues/review_test.go
+++ b/models/issues/review_test.go
@@ -132,11 +132,22 @@ func TestGetReviewersByIssueID(t *testing.T) {
 			UpdatedUnix: 946684814,
 		})
 
-	allReviews, err := issues_model.GetReviewersByIssueID(issue.ID)
-	for _, reviewer := range allReviews {
-		assert.NoError(t, reviewer.LoadReviewer(db.DefaultContext))
+	allReviews, err := issues_model.GetReviewsByIssueID(issue.ID)
+	assert.NoError(t, err)
+	for _, review := range allReviews {
+		assert.NoError(t, review.LoadReviewer(db.DefaultContext))
 	}
+	if assert.Len(t, allReviews, 3) {
+		for i, review := range allReviews {
+			assert.Equal(t, expectedReviews[i].Reviewer, review.Reviewer)
+			assert.Equal(t, expectedReviews[i].Type, review.Type)
+			assert.Equal(t, expectedReviews[i].UpdatedUnix, review.UpdatedUnix)
+		}
+	}
+
+	allReviews, err = issues_model.GetReviewsByIssueID(issue.ID)
 	assert.NoError(t, err)
+	assert.NoError(t, issues_model.LoadReviewers(db.DefaultContext, allReviews))
 	if assert.Len(t, allReviews, 3) {
 		for i, review := range allReviews {
 			assert.Equal(t, expectedReviews[i].Reviewer, review.Reviewer)
diff --git a/models/user/user.go b/models/user/user.go
index 57b2117bb9..07d8177b6a 100644
--- a/models/user/user.go
+++ b/models/user/user.go
@@ -20,6 +20,7 @@ import (
 	"code.gitea.io/gitea/modules/auth/openid"
 	"code.gitea.io/gitea/modules/auth/password/hash"
 	"code.gitea.io/gitea/modules/base"
+	"code.gitea.io/gitea/modules/container"
 	"code.gitea.io/gitea/modules/git"
 	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/setting"
@@ -910,6 +911,15 @@ func GetUserByID(ctx context.Context, id int64) (*User, error) {
 	return u, nil
 }
 
+// GetUserByIDs returns the user objects by given IDs if exists.
+func GetUserByIDs(ctx context.Context, ids []int64) ([]*User, error) {
+	users := make([]*User, 0, len(ids))
+	err := db.GetEngine(ctx).In("id", ids).
+		Table("user").
+		Find(&users)
+	return users, err
+}
+
 // GetPossibleUserByID returns the user if id > 0 or return system usrs if id < 0
 func GetPossibleUserByID(ctx context.Context, id int64) (*User, error) {
 	switch id {
@@ -924,6 +934,25 @@ func GetPossibleUserByID(ctx context.Context, id int64) (*User, error) {
 	}
 }
 
+// GetPossibleUserByIDs returns the users if id > 0 or return system users if id < 0
+func GetPossibleUserByIDs(ctx context.Context, ids []int64) ([]*User, error) {
+	uniqueIDs := container.SetOf(ids...)
+	users := make([]*User, 0, len(ids))
+	_ = uniqueIDs.Remove(0)
+	if uniqueIDs.Remove(-1) {
+		users = append(users, NewGhostUser())
+	}
+	if uniqueIDs.Remove(ActionsUserID) {
+		users = append(users, NewActionsUser())
+	}
+	res, err := GetUserByIDs(ctx, uniqueIDs.Values())
+	if err != nil {
+		return nil, err
+	}
+	users = append(users, res...)
+	return users, nil
+}
+
 // GetUserByNameCtx returns user by given name.
 func GetUserByName(ctx context.Context, name string) (*User, error) {
 	if len(name) == 0 {
diff --git a/models/webhook/webhook.go b/models/webhook/webhook.go
index e3f6b593d9..fc2bbed083 100644
--- a/models/webhook/webhook.go
+++ b/models/webhook/webhook.go
@@ -298,6 +298,12 @@ func (w *Webhook) HasPackageEvent() bool {
 		(w.ChooseEvents && w.HookEvents.Package)
 }
 
+// HasPullRequestReviewRequestEvent returns true if hook enabled pull request review request event.
+func (w *Webhook) HasPullRequestReviewRequestEvent() bool {
+	return w.SendEverything ||
+		(w.ChooseEvents && w.HookEvents.PullRequestReviewRequest)
+}
+
 // EventCheckers returns event checkers
 func (w *Webhook) EventCheckers() []struct {
 	Has  func() bool
@@ -329,6 +335,7 @@ func (w *Webhook) EventCheckers() []struct {
 		{w.HasRepositoryEvent, webhook_module.HookEventRepository},
 		{w.HasReleaseEvent, webhook_module.HookEventRelease},
 		{w.HasPackageEvent, webhook_module.HookEventPackage},
+		{w.HasPullRequestReviewRequestEvent, webhook_module.HookEventPullRequestReviewRequest},
 	}
 }
 
diff --git a/models/webhook/webhook_test.go b/models/webhook/webhook_test.go
index e05dcaba01..de6568c321 100644
--- a/models/webhook/webhook_test.go
+++ b/models/webhook/webhook_test.go
@@ -73,7 +73,7 @@ func TestWebhook_EventsArray(t *testing.T) {
 		"pull_request", "pull_request_assign", "pull_request_label", "pull_request_milestone",
 		"pull_request_comment", "pull_request_review_approved", "pull_request_review_rejected",
 		"pull_request_review_comment", "pull_request_sync", "wiki", "repository", "release",
-		"package",
+		"package", "pull_request_review_request",
 	},
 		(&Webhook{
 			HookEvent: &webhook_module.HookEvent{SendEverything: true},