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.

2 files changed, 27 insertions, 21 deletions

diff --git a/modules/structs/hook.go b/modules/structs/hook.go
index df5da6790f..cd91d4bc46 100644
--- a/modules/structs/hook.go
+++ b/modules/structs/hook.go
@@ -342,6 +342,10 @@ const (
 	HookIssueDemilestoned HookIssueAction = "demilestoned"
 	// HookIssueReviewed is an issue action for when a pull request is reviewed
 	HookIssueReviewed HookIssueAction = "reviewed"
+	// HookIssueReviewRequested is an issue action for when a reviewer is requested for a pull request.
+	HookIssueReviewRequested HookIssueAction = "review_requested"
+	// HookIssueReviewRequestRemoved is an issue action for removing a review request to someone on a pull request.
+	HookIssueReviewRequestRemoved HookIssueAction = "review_request_removed"
 )
 
 // IssuePayload represents the payload information that is sent along with an issue event.
@@ -381,14 +385,15 @@ type ChangesPayload struct {
 
 // PullRequestPayload represents a payload information of pull request event.
 type PullRequestPayload struct {
-	Action      HookIssueAction `json:"action"`
-	Index       int64           `json:"number"`
-	Changes     *ChangesPayload `json:"changes,omitempty"`
-	PullRequest *PullRequest    `json:"pull_request"`
-	Repository  *Repository     `json:"repository"`
-	Sender      *User           `json:"sender"`
-	CommitID    string          `json:"commit_id"`
-	Review      *ReviewPayload  `json:"review"`
+	Action            HookIssueAction `json:"action"`
+	Index             int64           `json:"number"`
+	Changes           *ChangesPayload `json:"changes,omitempty"`
+	PullRequest       *PullRequest    `json:"pull_request"`
+	RequestedReviewer *User           `json:"requested_reviewer"`
+	Repository        *Repository     `json:"repository"`
+	Sender            *User           `json:"sender"`
+	CommitID          string          `json:"commit_id"`
+	Review            *ReviewPayload  `json:"review"`
 }
 
 // JSONPayload FIXME
diff --git a/modules/structs/pull.go b/modules/structs/pull.go
index f64bb83af9..a4a6f60b05 100644
--- a/modules/structs/pull.go
+++ b/modules/structs/pull.go
@@ -9,19 +9,20 @@ import (
 
 // PullRequest represents a pull request
 type PullRequest struct {
-	ID        int64      `json:"id"`
-	URL       string     `json:"url"`
-	Index     int64      `json:"number"`
-	Poster    *User      `json:"user"`
-	Title     string     `json:"title"`
-	Body      string     `json:"body"`
-	Labels    []*Label   `json:"labels"`
-	Milestone *Milestone `json:"milestone"`
-	Assignee  *User      `json:"assignee"`
-	Assignees []*User    `json:"assignees"`
-	State     StateType  `json:"state"`
-	IsLocked  bool       `json:"is_locked"`
-	Comments  int        `json:"comments"`
+	ID                 int64      `json:"id"`
+	URL                string     `json:"url"`
+	Index              int64      `json:"number"`
+	Poster             *User      `json:"user"`
+	Title              string     `json:"title"`
+	Body               string     `json:"body"`
+	Labels             []*Label   `json:"labels"`
+	Milestone          *Milestone `json:"milestone"`
+	Assignee           *User      `json:"assignee"`
+	Assignees          []*User    `json:"assignees"`
+	RequestedReviewers []*User    `json:"requested_reviewers"`
+	State              StateType  `json:"state"`
+	IsLocked           bool       `json:"is_locked"`
+	Comments           int        `json:"comments"`
 
 	HTMLURL  string `json:"html_url"`
 	DiffURL  string `json:"diff_url"`