Re: [PATCH v3] fast-export: fix regression skipping some merge-commits

> 7199203937 (object_array: add and use `object_array_pop()`, 2017-09-23)
> noted that the pattern `object = array.objects[--array.nr].item` could
> be abstracted as `object = object_array_pop(&array)`.
>
> Unfortunately, one of the conversions was horribly wrong. Between
> grabbing the last object (i.e., peeking at it) and decreasing the object
> count, the original code would sometimes return early. The updated code
> on the other hand, will always pop the last element, then maybe do the
> early return without doing anything with the object.
>
> The end result is that merge commits where all the parents have still
> not been exported will simply be dropped, meaning that they will be
> completely missing from the exported data.
>
> Re-add a commit when it is not yet time to handle it. An alternative
> that was considered was to peek-then-pop. That carries some risk with it
> since the peeking and poping need to act on the same object, in a

> concerted fashion.
>
> Add a test that would have caught this.
>
> Reported-by: Isaac Chou <Isaac.Chou@microfocus.com>
> Analyzed-by: Isaac Chou <Isaac.Chou@microfocus.com>
> Helped-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
> Signed-off-by: Martin Ågren <martin.agren@gmail.com>