René Scharfe <l.s.r@xxxxxx> writes:
>> /*
>> * NEEDSWORK:
>> * There is absolutely no reason to write this as a blob object
>> - * and create a phony cache entry just to leak. This hack is
>> - * primarily to get to the write_entry() machinery that massages
>> - * the contents to work-tree format and writes out which only
>> - * allows it for a cache entry. The code in write_entry() needs
>> - * to be refactored to allow us to feed a <buffer, size, mode>
>> - * instead of a cache entry. Such a refactoring would help
>> - * merge_recursive as well (it also writes the merge result to the
>> - * object database even when it may contain conflicts).
>> + * and create a phony cache entry. This hack is primarily to get
>> + * to the write_entry() machinery that massages the contents to
>> + * work-tree format and writes out which only allows it for a
>> + * cache entry. The code in write_entry() needs to be refactored
>> + * to allow us to feed a <buffer, size, mode> instead of a cache
>> + * entry. Such a refactoring would help merge_recursive as well
>> + * (it also writes the merge result to the object database even
>> + * when it may contain conflicts).
>> */
>> if (write_sha1_file(result_buf.ptr, result_buf.size,
>> blob_type, oid.hash))
>
> Random observation: Using pretend_sha1_file here would at least avoid
> writing the blob.
Yup, you should have told that to me back in Aug 2008 ;-) when I did
0cf8581e ("checkout -m: recreate merge when checking out of unmerged
index", 2008-08-30); pretend_sha1_file() was available since early
2007, and there is no excuse that this codepath did not use it.
>
>> @@ -251,6 +251,7 @@ static int checkout_merged(int pos, const struct checkout *state)
>> if (!ce)
>> die(_("make_cache_entry failed for path '%s'"), path);
>> status = checkout_entry(ce, state, NULL);
>> + free(ce);
>> return status;
>> }
>
> I wonder if that's safe. Why document a leak when it could have been
> plugged this easily instead?
>
> A leak is better than a use after free, so
> let's be extra careful here. Would it leave the index inconsistent? Or
> perhaps freeing it has become safe in the meantime?
>
> @Junio: Do you remember the reason for the leaks in 0cf8581e330
> (checkout -m: recreate merge when checking out of unmerged index).
Yes.
In the very old days it was not allowed to free(3) contents of
active_cache[] and this was an old brain fart that came out of
inertia. We are manufacturing a brand new ce, only to feed it to
checkout_entry() without even registering it to the active_cache[]
array, and the ancient rule doesn't even apply to such a case.
So I think it was safe to free(3) even back then.
> And result_buf is still leaked here, right?
Good spotting. It typically would make a larger leak than a single
ce, I would suppose ;-)