Re: [PATCH] t4202 (log): add failing test for log with subtree

From: Ramkumar Ramachandra <artagnon@gmail.com>
Date: Apr 22, 2013, 18:00 UTC
Message-ID: <CALkWK0madWxOSraZw6u8U_afVeK8tyMB_+D59n1vSBmobxGqqg@mail.gmail.com>
In-Reply-To: <7vk3nupltx.fsf@alter.siamese.dyndns.org>

Junio C Hamano wrote:

Show 9 quoted lines

> [...]
>  (3) When (1) notices that the path being followed did not exist in
>      any of the parents (be it a merge or a non-merge) and finds a
>      different path with a similar looking content, it _switches_
>      the pathspec to it, but the single pathspec it uses is a global
>      state and affects traversals of other ancestry paths at the
>      same time.  Because of this, "--follow" will not work correctly
>      in a history that contains merges.  It often _appears_ to work
>      only by accident.

This explanation is all very nice, but isn't it completely tangential to the issue at hand?

Let's say I have a subtree merge M located at HEAD~4.  I ask for the
log of 'HEAD~4 -- README' with --follow.  It follows until it gets to
M: at M, M^1:README is missing, but M^2:README is present.  Should it
follow down and show the history of M^2:README?

You can reserve the discussion about --follow working in the general case for another thread. Meanwhile, you're evading the issue of assuming that all trees are read into /, and are really representing the same project's history, while this is not the case.