glib: collections: Change early return to assertion in collection reserve functions

On early return this would cause out of bounds writes from the caller,
and this condition should never really happen.

Author: sdroege

glib/src/collections/ptr_slice.rs

@@ -707,10 +707,7 @@ impl<T: TransparentPtrType> PtrSlice<T> {
         let new_capacity =
             usize::next_power_of_two(std::cmp::max(self.len + additional, MIN_SIZE) + 1);
         assert_ne!(new_capacity, 0);
-
-        if new_capacity <= self.capacity {
-            return;
-        }
+        assert!(new_capacity > self.capacity);
 
         unsafe {
             let ptr = if self.capacity == 0 {

glib/src/collections/slice.rs

@@ -623,10 +623,7 @@ impl<T: TransparentType> Slice<T> {
             MIN_SIZE / mem::size_of::<T>(),
         ));
         assert_ne!(new_capacity, 0);
-
-        if new_capacity <= self.capacity {
-            return;
-        }
+        assert!(new_capacity > self.capacity);
 
         unsafe {
             let ptr = if self.capacity == 0 {

glib/src/collections/strv.rs

@@ -667,10 +667,7 @@ impl StrV {
         let new_capacity =
             usize::next_power_of_two(std::cmp::max(self.len + additional, MIN_SIZE) + 1);
         assert_ne!(new_capacity, 0);
-
-        if new_capacity <= self.capacity {
-            return;
-        }
+        assert!(new_capacity > self.capacity);
 
         unsafe {
             let ptr = if self.capacity == 0 {