Re: [PATCH v2 2/3] gitweb: Link to 7-char+ SHA1s, not only 8-char+

From: Jakub Narębski <jnareb@gmail.com>
Date: Oct 14, 2016, 17:45 UTC
Message-ID: <3fa9902f-3b01-5ec6-8129-34cff4c7cac9@gmail.com>
In-Reply-To: <20161006091135.29590-3-avarab@gmail.com>

W dniu 06.10.2016 o 11:11, Ævar Arnfjörð Bjarmason pisze:

Show 12 quoted lines

> Change the minimum length of an abbreviated object identifier in the
> commit message gitweb tries to turn into link from 8 hexchars to 7.
> 
> This arbitrary minimum length of 8 was introduced in bfe2191 ("gitweb:
> SHA-1 in commit log message links to "object" view", 2006-12-10), but
> the default abbreviation length is 7, and has been for a long time.
> 
> It's still possible to reference SHA1s down to 4 characters in length,
> see v1.7.4-1-gdce9648's MINIMUM_ABBREV, but I can't see how to make
> git actually produce that, so I doubt anyone is putting that into log
> messages in practice, but people definitely do put 7 character SHA1s
> into log messages.

That's nice explanation why we want to support 7 character SHA-1 (it is the default, and was seen in the wild), but don't need to support shorter lengths.

Another reason (just for completeness; you don't need to put it in the commit message) to not go below 7 characters is that with decreasing length there is more and more chance for false positives (like 'beef' or 'caffee' for 4-char or 5-char hexstring), as I wrote previously.

s/SHA1/SHA-1/g in above paragraph (for correctness and consistency).

Show 6 quoted lines

> 
> I think it's fairly dubious to link to things matching [0-9a-fA-F]
> here as opposed to just [0-9a-f], that dates back to the initial
> version of gitweb from 161332a ("first working version",
> 2005-08-07). Git will accept all-caps SHA1s, but didn't ever produce
> them as far as I can tell.

All right. If we decide to be more strict in what we accept, we can do it in a separate commit.

> 
> Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>

Acked-by: Jakub Narębski <jnareb@gmail.com>

Show 14 quoted lines

> ---
>  gitweb/gitweb.perl | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/gitweb/gitweb.perl b/gitweb/gitweb.perl
> index cba7405..92b5e91 100755
> --- a/gitweb/gitweb.perl
> +++ b/gitweb/gitweb.perl
> @@ -2036,7 +2036,7 @@ sub format_log_line_html {
>  	my $line = shift;
>  
>  	$line = esc_html($line, -nbsp=>1);
> -	$line =~ s{\b([0-9a-fA-F]{8,40})\b}{
> +	$line =~ s{\b([0-9a-fA-F]{7,40})\b}{

By the way, it is quite long commit message for one character change. Not that it is a bad thing...

>  		$cgi->a({-href => href(action=>"object", hash=>$1),
>  					-class => "text"}, $1);
>  	}eg;
>