builtin-clone does not fallback to copy when link fails

> 
> When cloning with the new builtin-clone, if the src repo is not
> on the same disk as the dest repo, cloning fails. This is because
> hard linking does not fall back to copying like the shell version
> did.
> 
> The shell version also made a distinction between defaulting to
> hard linking and an explicit request to hard link. In the latter
> case it would not fall back to copying, but would die.

> Brandon Casey wrote:
>> When cloning with the new builtin-clone, if the src repo is not
>> on the same disk as the dest repo, cloning fails. This is because
>> hard linking does not fall back to copying like the shell version
>> did.
>>
>> The shell version also made a distinction between defaulting to
>> hard linking and an explicit request to hard link. In the latter
>> case it would not fall back to copying, but would die.
> 
> Something like this (if not too ugly) might do the trick:
> 
> diff --git a/builtin-clone.c b/builtin-clone.c
> index 8713128..1062371 100644
> --- a/builtin-clone.c
> +++ b/builtin-clone.c
> @@ -208,11 +208,17 @@ static void copy_or_link_directory(char *src, char *dest)
>  		if (unlink(dest) && errno != ENOENT)
>  			die("failed to unlink %s\n", dest);
>  		if (option_no_hardlinks) {
> +FALLBACK_TO_COPY:
>  			if (copy_file(dest, src, 0666))
>  				die("failed to copy file to %s\n", dest);
>  		} else {
> -			if (link(src, dest))
> +			if (link(src, dest)) {
> +				if (errno == EXDEV && !option_local) {

> Brandon Casey wrote:
> > 
> > When cloning with the new builtin-clone, if the src repo is not
> > on the same disk as the dest repo, cloning fails. This is because
> > hard linking does not fall back to copying like the shell version
> > did.
> > 
> > The shell version also made a distinction between defaulting to
> > hard linking and an explicit request to hard link. In the latter
> > case it would not fall back to copying, but would die.

> On Tue, 20 May 2008, Brandon Casey wrote:
> 
>> Brandon Casey wrote:
>>> When cloning with the new builtin-clone, if the src repo is not
>>> on the same disk as the dest repo, cloning fails. This is because
>>> hard linking does not fall back to copying like the shell version
>>> did.
>>>
>>> The shell version also made a distinction between defaulting to
>>> hard linking and an explicit request to hard link. In the latter
>>> case it would not fall back to copying, but would die.
> 
> I think that the shell version's behavior changed at some point, too. I 
> think I tried at some point to figure out exactly what the specified 
> behavior was, and couldn't come up with anything that entirely matched.
> 
>> Something like this (if not too ugly) might do the trick:
> 
> I think that's good behavior, but it's kind of ugly. How about:
> 
> -----
> commit 83afef6a159365c1b9a7a1961cb4c95df24fbcac
> Author: Daniel Barkalow <barkalow@iabervon.org>
> Date:   Tue May 20 14:15:14 2008 -0400
> 
>     Fall back to copying if hardlinking fails
>     
>     Note that it stops trying hardlinks if any fail.
>     
>     Signed-off-by: Daniel Barkalow <barkalow@iabervon.org>
> 
> diff --git a/builtin-clone.c b/builtin-clone.c
> index 8713128..42633ae 100644
> --- a/builtin-clone.c
> +++ b/builtin-clone.c
> @@ -207,13 +207,15 @@ static void copy_or_link_directory(char *src, char *dest)
>  
>  		if (unlink(dest) && errno != ENOENT)
>  			die("failed to unlink %s\n", dest);
> -		if (option_no_hardlinks) {
> -			if (copy_file(dest, src, 0666))
> -				die("failed to copy file to %s\n", dest);
> -		} else {
> -			if (link(src, dest))
> +		if (!option_no_hardlinks) {
> +			if (!link(src, dest))
> +				continue;
> +			if (option_local)
>  				die("failed to create link %s\n", dest);
> +			option_no_hardlinks = 1;
>  		}
> +		if (copy_file(dest, src, 0666))
> +			die("failed to copy file to %s\n", dest);
>  	}
>  }

> How about:
> 
> -----
> commit 83afef6a159365c1b9a7a1961cb4c95df24fbcac
> Author: Daniel Barkalow <barkalow@iabervon.org>
> Date:   Tue May 20 14:15:14 2008 -0400
> 
>     Fall back to copying if hardlinking fails
>     
>     Note that it stops trying hardlinks if any fail.
>     
>     Signed-off-by: Daniel Barkalow <barkalow@iabervon.org>