Issue.assignees can be null

src/types/api/edit/issue.rs

@@ -34,6 +34,7 @@ impl EditIssueOption {
             assignee: issue.assignee.as_ref().map(|user| user.login_name.clone()),
             assignees: issue
                 .assignees
+                .unwrap_or_default()
                 .iter()
                 .map(|user| user.login_name.clone())
                 .collect::<Vec<_>>(),

src/types/api/issue.rs

@@ -57,7 +57,7 @@ pub struct Issue {
     /// The user assigned to the issue.
     pub assignee: Option<User>,
     /// List of assignees.
-    pub assignees: Vec<User>,
+    pub assignees: Option<Vec<User>>,
     /// The body of the issue.
     pub body: String,
     /// The date and time when the issue was closed (if closed).