Support endpoint to collect merge requests closing an issue (#421)

issues.go

@@ -362,6 +362,39 @@ func (s *IssuesService) DeleteIssue(pid interface{}, issue int, options ...Optio
 	return s.client.Do(req, nil)
 }
 
+// ListMergeRequestsClosingIssueOptions represents the available
+// ListMergeRequestsClosingIssue() options.
+//
+// GitLab API docs:
+// https://docs.gitlab.com/ce/api/issues.html#list-merge-requests-that-will-close-issue-on-merge
+type ListMergeRequestsClosingIssueOptions ListOptions
+
+// ListMergeRequestsClosingIssue gets all the merge requests that will close
+// issue when merged.
+//
+// GitLab API docs:
+// https://docs.gitlab.com/ce/api/issues.html#list-merge-requests-that-will-close-issue-on-merge
+func (s *IssuesService) ListMergeRequestsClosingIssue(pid interface{}, issue int, opt *ListMergeRequestsClosingIssueOptions, options ...OptionFunc) ([]*MergeRequest, *Response, error) {
+	project, err := parseID(pid)
+	if err != nil {
+		return nil, nil, err
+	}
+	u := fmt.Sprintf("/projects/%s/issues/%d/closed_by", url.QueryEscape(project), issue)
+
+	req, err := s.client.NewRequest("GET", u, opt, options)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	var m []*MergeRequest
+	resp, err := s.client.Do(req, &m)
+	if err != nil {
+		return nil, resp, err
+	}
+
+	return m, resp, err
+}
+
 // SetTimeEstimate sets the time estimate for a single project issue.
 //
 // GitLab API docs:

merge_requests.go

@@ -348,7 +348,7 @@ func (s *MergeRequestsService) ListMergeRequestPipelines(pid interface{}, mergeR
 	if err != nil {
 		return nil, nil, err
 	}
-	u := fmt.Sprintf("projects/%s/merge_requests/%v/pipelines", url.QueryEscape(project), mergeRequest)
+	u := fmt.Sprintf("projects/%s/merge_requests/%d/pipelines", url.QueryEscape(project), mergeRequest)
 
 	req, err := s.client.NewRequest("GET", u, nil, options)
 	if err != nil {
@@ -381,7 +381,7 @@ func (s *MergeRequestsService) GetIssuesClosedOnMerge(pid interface{}, mergeRequ
 	if err != nil {
 		return nil, nil, err
 	}
-	u := fmt.Sprintf("/projects/%s/merge_requests/%v/closes_issues", url.QueryEscape(project), mergeRequest)
+	u := fmt.Sprintf("/projects/%s/merge_requests/%d/closes_issues", url.QueryEscape(project), mergeRequest)
 
 	req, err := s.client.NewRequest("GET", u, opt, options)
 	if err != nil {