When vimdiff3 was added in 7c147b77d3 (mergetools: add vimdiff3 mode,
2014-04-20), the description made clear the intention:
It's similar to the default, except that the other windows are
hidden. This ensures that removed/added colors are still visible on
the main merge window, but the other windows not visible.
However, in 0041797449 (vimdiff: new implementation with layout support,
2022-03-30) this was broken by generating a command that never creates
windows, and therefore vim never shows the diff.
The layout support implementation broke the whole purpose of vimdiff3,
and simply shows MERGED, which is no different from simply opening the
file with vim.
In order to show the diff, the windows need to be created first, and
then when they are hidden the diff remains (if hidenoff isn't set), but
by setting the `hidden` option the initial buffers are marked as hidden
thus making the feature work.
Suggested-by: Fernando Ramos <greenfoo@u92.eu>
Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
Reviewed-by: Fernando Ramos <greenfoo@u92.eu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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