Re: git-apply{,mbox,patch} should default to --unidiff-zero

[Johannes Schindelin <Johannes.Schindelin@gmx.de>]

Hi,

On Fri, 6 Jul 2007, Adrian Bunk wrote:

> On Fri, Jul 06, 2007 at 02:18:46AM +0100, Johannes Schindelin wrote:
> 
> > On Fri, 6 Jul 2007, Adrian Bunk wrote:
> > 
> > > git-apply{,mbox,patch} should default to doing --unidiff-zero:
> > 
> > But is that not dangerous? At least now the committer has some 
> > safeguard against this kind of mistakes. Because you can easily 
> > introduce mistakes that way.
> 
> you are saying "easily".
> 
> Did you ever actually run into such a problem?

Not yet, thankfully.

> You must do something like "diff -U0" or manually editing patches for 
> creating such patches, and that's very unusual.

The point is that the _committer_ is not necessarily involved in that 
business.

And "git apply" is strict for a reason. It catches possibly unwanted 
things much earlier than patch. I _want_ to be warned that somebody is 
introducing some code at a certain position, which might, or might not be 
correct. apply has no way to tell, since there is no context to at least 
minimally verify.

> And although GNU patch (which has a much bigger userbase than git) 
> applies such patches without any warning I don't remember having ever 
> seen what you call "easily".

GNU patch is very sloppy. And I had to fix up quite a number of patches 
which were "successfully" applied, but did not do what they were supposed 
to do. The recent "GNU patch applies _indented_ _context_ diffs" fracass 
is only one example why I prefer git apply.

Unfortunately, I do not off-hand remember if I had to fix up a 
unified-zero patch that GNU patch applied, but I do know this:

	if "git am" learns to apply unified-zero by default, the first 
	thing I will do is patch it in my Git branch to _not_ do that. I 
	do _not_ want that. I want to be warned.

	I can still decide that it is probably okay, but I will make 
	_damned_ _well_ sure afterwards that it did something sensible. I 
	will _only_ apply such a scrutiny when git apply refused to apply 
	a unified-zero patch, and I decided to apply it nevertheless.

Ciao,
Dscho