Re: [PATCH] mergetool: use more conservative temporary filenames

From: Junio C Hamano <gitster@pobox.com>
Date: Oct 9, 2014, 18:36 UTC
Message-ID: <xmqq8ukp6qgf.fsf@gitster.dls.corp.google.com>
In-Reply-To: <1412758562-25402-1-git-send-email-davvid@gmail.com>

David Aguilar <davvid@gmail.com> writes:

Show 41 quoted lines

> Avoid filenames with multiple dots so that overly-picky tools do
> not misinterpret their extension.
>
> Previously, foo/bar.ext in the worktree would result in e.g.
>
> 	foo/bar.ext.BASE.1234.ext
>
> This can be improved by having only a single .ext and using
> underscore instead of dot so that the extension cannot be
> misinterpreted.  The resulting path becomes:
>
> 	foo/bar_BASE_1234.ext
>
> Suggested-by: Sergio Ferrero <sferrero@ensoftcorp.com>
> Signed-off-by: David Aguilar <davvid@gmail.com>
> ---
>  git-mergetool.sh | 14 +++++++++-----
>  1 file changed, 9 insertions(+), 5 deletions(-)
>
> diff --git a/git-mergetool.sh b/git-mergetool.sh
> index 9a046b7..1f33051 100755
> --- a/git-mergetool.sh
> +++ b/git-mergetool.sh
> @@ -228,11 +228,15 @@ merge_file () {
>  		return 1
>  	fi
>  
> -	ext="$$$(expr "$MERGED" : '.*\(\.[^/]*\)$')"
> -	BACKUP="./$MERGED.BACKUP.$ext"
> -	LOCAL="./$MERGED.LOCAL.$ext"
> -	REMOTE="./$MERGED.REMOTE.$ext"
> -	BASE="./$MERGED.BASE.$ext"
> +	ext=$(expr "$MERGED" : '.*\(\.[^/]*\)$')
> +	base=$(basename "$MERGED" "$ext")
> +	dir=$(dirname "$MERGED")
> +	suffix="$$""$ext"
> +
> +	BACKUP="$dir/$base"_BACKUP_"$suffix"
> +	BASE="$dir/$base"_BASE_"$suffix"
> +	LOCAL="$dir/$base"_LOCAL_"$suffix"
> +	REMOTE="$dir/$base"_REMOTE_"$suffix"

We used to feed "./foo/bar.ext.BASE.1234.ext"; with this patch we feed "foo/bar_BASE_1234.ext".

It does make this particular example look prettier, but is the droppage of "./" intentional and is free of unintended ill side effects?

We avoid "local" and bash-isms, so I'd prefer to see us not to introduce new temporary variables unnecessarily. I think we can at least do without basename/dirname in this case, perhaps like so:

	if BASE=$(expr "$MERGED" : '\(.*\)\.[^/]*$')
        then
        	ext=$(expr "$MERGED" : '.*\(\.[^/]*\)$')
	else
        	ext= BASE=$MERGED
	fi
        BACKUP="${BASE}_BACKUP_$$$ext"
        LOCAL="${BASE}_LOCAL_$$$ext"
        REMOTE="${BASE}_REMOTE_$$$ext"
        BASE="${BASE}_BASE_$$$ext"
        
But I do not have very strong opinion either way.  I just didn't
want to have to think about the leading "./" ;-)