Re: gitignore design

From: Nguyen Thai Ngoc Duy <pclouds@gmail.com>
Date: Jul 30, 2011, 03:10 UTC
Message-ID: <CACsJy8CurvKd_=hdRQyjjzWLvKF0jbWOQhbLSsmk1BqB_dK3og@mail.gmail.com>
In-Reply-To: <201107292339.51753.jnareb@gmail.com>

2011/7/30 Jakub Narebski <jnareb@gmail.com>

> True, it is *assume-unchanged*, not ignore-changes bit; though the latter
> would be also possible to implement, I think... but having some file not
> changing and marking it as such for better performance is saner use case
> than tracking some file but not really tracking it.

If you just want to ignore some files (or paths), then adding --exclude option to diff machinery may be a better option. --assume-unchanged is too low-level, and not really convenient to use.

Show 7 quoted lines

> > No code reference, sorry, because I'm just parrotting what I've read
> > elsewhere on the list, for example,
> > http://thread.gmane.org/gmane.comp.version-control.git/146082/focus=146353
>
> Well, there is hint that there might be problems, but not really says
> that they are, and where (if one is lying about assume unchanged by changing
> assume-unchanged file).

There were problems in the past. See aecda37 (do not overwrite files marked "assume unchanged" - 2010-05-01)

The only place that relies on checking files uptodate (which can be faked by assume-unchanged bit) before overwriting them is unpack-trees.c, verify_update_1(). With that fix in place, I think assume-unchanged bit is safe now. However, as long as we don't explicitly state that we will not carelessly overwrite assume-unchanged files, there are still chances that some optimizations in future may make it dangerous again. -- Duy