api: fix nil pointer dereference when listing user repos (#8069)

Co-authored-by: Joe Chen <jc@unknwon.io>

CHANGELOG.md

@@ -21,6 +21,7 @@ All notable changes to Gogs are documented in this file.
 
 - Submodules using `ssh://` protocol and a port number are not rendered correctly. [#4941](https://github.com/gogs/gogs/issues/4941)
 - Missing link to user profile on the first commit in commits history page. [#7404](https://github.com/gogs/gogs/issues/7404)
+- Route `GET /api/v1/user/repos` responses 500 when accessible repositories contain forks. [#8069](https://github.com/gogs/gogs/pull/8069)
 
 ## 0.13.3
 

internal/route/api/v1/repo/repo.go

@@ -112,19 +112,28 @@ func listUserRepositories(c *context.APIContext, username string) {
 		return
 	}
 
-	accessibleRepos, err := database.Handle.Repositories().GetByCollaboratorIDWithAccessMode(c.Req.Context(), user.ID)
+	accessibleReposWithAccessMode, err := database.Handle.Repositories().GetByCollaboratorIDWithAccessMode(c.Req.Context(), user.ID)
 	if err != nil {
 		c.Error(err, "get repositories accesses by collaborator")
 		return
 	}
 
+	accessibleRepos := make([]*database.Repository, 0, len(accessibleReposWithAccessMode))
+	for repo := range accessibleReposWithAccessMode {
+		accessibleRepos = append(accessibleRepos, repo)
+	}
+	if err = database.RepositoryList(accessibleRepos).LoadAttributes(); err != nil {
+		c.Error(err, "load attributes for accessible repositories")
+		return
+	}
+
 	numOwnRepos := len(ownRepos)
-	repos := make([]*api.Repository, 0, numOwnRepos+len(accessibleRepos))
+	repos := make([]*api.Repository, 0, numOwnRepos+len(accessibleReposWithAccessMode))
 	for _, r := range ownRepos {
 		repos = append(repos, r.APIFormatLegacy(&api.Permission{Admin: true, Push: true, Pull: true}))
 	}
 
-	for repo, access := range accessibleRepos {
+	for repo, access := range accessibleReposWithAccessMode {
 		repos = append(repos,
 			repo.APIFormatLegacy(&api.Permission{
 				Admin: access >= database.AccessModeAdmin,