Fix case label removal

src/github/issue.rs

@@ -267,11 +267,16 @@ impl Issue {
         log::info!("remove_labels from {}: {:?}", self.global_id(), labels);
 
         // Don't try to remove labels not already present on this issue.
+        // Use case-insensitive comparison to match GitHub's behavior when adding labels.
         let labels = labels
             .into_iter()
-            .filter(|l| self.labels().contains(l))
+            .filter_map(|l| {
+                self.labels()
+                    .iter()
+                    .find(|existing| existing.name.to_lowercase() == l.name.to_lowercase())
+                    .cloned()
+            })
             .collect::<Vec<_>>();
-
         log::info!(
             "remove_labels: {} filtered to {:?}",
             self.global_id(),
@@ -959,3 +964,44 @@ impl IssueRepository {
         Ok(permission)
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::Label;
+
+    #[test]
+    fn test_case_insensitive_label_matching() {
+        let issue_labels = vec![
+            Label {
+                name: "E-needs-mcve".to_string(),
+            },
+            Label {
+                name: "T-compiler".to_string(),
+            },
+        ];
+
+        // Simulate what remove_labels does with the fix
+        let to_remove = vec![
+            Label {
+                name: "e-needs-mcve".to_string(),
+            }, // lowercase version
+        ];
+
+        let matched: Vec<Label> = to_remove
+            .into_iter()
+            .filter_map(|l| {
+                issue_labels
+                    .iter()
+                    .find(|existing| existing.name.to_lowercase() == l.name.to_lowercase())
+                    .cloned()
+            })
+            .collect();
+
+        assert_eq!(
+            matched,
+            vec![Label {
+                name: "E-needs-mcve".to_string()
+            }]
+        );
+    }
+}