feat: add State::remove_entry_at_index(pos) by position.

Author: Byron

gix-index/src/access/mod.rs

@@ -518,7 +518,8 @@ impl State {
 
     /// Physically remove all entries for which `should_remove(idx, path, entry)` returns `true`, traversing them from first to last.
     ///
-    /// Note that the memory used for the removed entries paths is not freed, as it's append-only.
+    /// Note that the memory used for the removed entries paths is not freed, as it's append-only, and
+    /// that some extensions might refer to paths which are now deleted.
     ///
     /// ### Performance
     ///
@@ -534,6 +535,16 @@ impl State {
             res
         });
     }
+
+    /// Physically remove the entry at `index`, or panic if the entry didn't exist.
+    ///
+    /// This call is typically made after looking up `index`, so it's clear that it will not panic.
+    ///
+    /// Note that the memory used for the removed entries paths is not freed, as it's append-only, and
+    /// that some extensions might refer to paths which are now deleted.
+    pub fn remove_entry_at_index(&mut self, index: usize) -> Entry {
+        self.entries.remove(index)
+    }
 }
 
 /// Extensions

gix-index/tests/index/access.rs

@@ -214,6 +214,18 @@ fn remove_entries() {
     file.remove_entries(|_, _, _| unreachable!("should not be called"));
 }
 
+#[test]
+fn remove_entry_at_index() {
+    let mut file = Fixture::Loose("conflicting-file").open();
+
+    file.remove_entry_at_index(0);
+    assert_eq!(file.entries().len(), 2);
+    file.remove_entry_at_index(0);
+    assert_eq!(file.entries().len(), 1);
+    file.remove_entry_at_index(0);
+    assert_eq!(file.entries().len(), 0);
+}
+
 #[test]
 fn sort_entries() {
     let mut file = Fixture::Generated("v4_more_files_IEOT").open();