Re: [PATCH v4 02/23] read-cache.c: remove 'const' from index_has_changes()

From: Junio C Hamano <gitster@pobox.com>
Date: Sep 17, 2018, 16:25 UTC
Message-ID: <xmqqo9cw851q.fsf@gitster-ct.c.googlers.com>
In-Reply-To: <20180915161759.8272-3-pclouds@gmail.com>

Nguyễn Thái Ngọc Duy  <pclouds@gmail.com> writes:

> This function calls do_diff_cache() which eventually needs to set this
> "istate" to unpack_options->src_index (*). This is an unfortunate fact
> that unpack_trees() _will_ destroy src_index so we can't really pass a

Wasn't the whole point of introducing src_index and dst_index to unpack-trees API so that we can keep the src_index read-only by writing the result of merge to a separate in-core dst_index?

What does the above exactly mean by "will destroy src_index"? Is it now fundamental that src_index needs to lack constness, or is it something easy to fix?

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