From fe02f4da2ca6092a801aebcc644844fc915aa187 Mon Sep 17 00:00:00 2001
From: kolaente <k@knt.li>
Date: Sun, 3 Mar 2024 11:40:30 +0100
Subject: [PATCH] fix(project): check for project nesting cycles with a single
 recursive cte instead of a loop

---
 pkg/models/project.go | 34 ++++++++++++++++++++++++++--------
 1 file changed, 26 insertions(+), 8 deletions(-)

diff --git a/pkg/models/project.go b/pkg/models/project.go
index 0e5992156..376c310c3 100644
--- a/pkg/models/project.go
+++ b/pkg/models/project.go
@@ -667,12 +667,34 @@ func checkProjectBeforeUpdateOrDelete(s *xorm.Session, project *Project) (err er
 			}
 		}
 
-		var parent *Project
-		parent, err = GetProjectSimpleByID(s, project.ParentProjectID)
+		allProjects := make(map[int64]*Project)
+		err = s.SQL(`WITH RECURSIVE all_projects AS (
+		    SELECT
+		        p.id,
+		        p.parent_project_id
+		    FROM
+		        projects p
+		    WHERE
+		        p.id = ?
+		    UNION ALL
+		    SELECT
+		        p.id,
+		        p.parent_project_id
+		    FROM
+		        Projects p
+		            INNER JOIN all_projects pc ON p.ID = pc.parent_project_id
+		)
+		SELECT
+		    *
+		FROM
+		    all_projects`, project.ParentProjectID).Find(&allProjects)
 		if err != nil {
-			return err
+			return
 		}
 
+		var parent *Project
+		parent = allProjects[project.ParentProjectID]
+
 		// Check if there's a cycle in the parent relation
 		parentsVisited := make(map[int64]bool)
 		parentsVisited[project.ID] = true
@@ -681,11 +703,7 @@ func checkProjectBeforeUpdateOrDelete(s *xorm.Session, project *Project) (err er
 				break
 			}
 
-			// FIXME: Can we do this with better performance?
-			parent, err = GetProjectSimpleByID(s, parent.ParentProjectID)
-			if err != nil {
-				return err
-			}
+			parent = allProjects[parent.ParentProjectID]
 
 			if parentsVisited[parent.ID] {
 				return &ErrProjectCannotHaveACyclicRelationship{