Re: Bizarre missing changes (git bug?)

From: Roman Zippel <zippel@linux-m68k.org>
Date: Jul 26, 2008, 03:12 UTC
Message-ID: <200807260512.40088.zippel@linux-m68k.org>
In-Reply-To: <alpine.LFD.1.10.0807211331390.31863@woody.linux-foundation.org>

Hi,

On Monday 21. July 2008, Linus Torvalds wrote:

Show 12 quoted lines

> Read up on '--full-history'.
>
> By default, git simplifies the history for logs that have path
> simplification: only walking down the side of a merge that all the data
> came from (ie the unchanged side). So it only leaves merges around if
> there was changes from _all_ parents.
>
> So without --full-history, if any parent matches the state, it just
> removes the merge and picks that parent that contained all the state.
> Obviously, any changes to that file can be sufficiently explained by
> walking just that limited history, because they must have changed in
> _that_ history too!

Is that really a good default behaviour? Is there a way to change that default?

I'm currently looking into converting the m68k CVS repository and I'd like to properly regenerate it as two separate lines of development. The problem is if I look at the file history, I often only see one side of the changes when things got merged because of this default. What makes this worse is that graphical front ends may inherit this behaviour. I tested this with qgit and it only shows half of the history. giggle retrieves the history like --full-history, but it lacks empty merges, so it makes it harder to see what got merged when. For example a history that actually looks this:

linux -+-----import----+-----------import----+------... m68k \-commit-commit-\-merge-commit-commit-\-merge...

Without the merges it looks like this:

linux -+-----import----------------import--------------+... m68k \-commit-commit---------commit-commit \...

And without --full-history these "loose ends" aren't visible as in qgit.

When researching historical changes one wants to know when something was introduced and when it was merged, but this simplification makes it harder than it really has to be. IMO the default should be to show the complete history, so one doesn't miss something by accident that might be important or as the original example shows it might be confusing if one sees a change with "git log --stat id.." and the change disappears when one looks at "git log path".

bye, Roman