Subject: Re: gitweb: local configuration not found

From: Ævar Arnfjörð Bjarmason <[email-masked]>
Date: Wed, 05 Dec 2018 20:11:17 +0100

On Wed, Dec 05 2018, Jonathan Nieder wrote:

> Martin Mares wrote[1]:
>
>> After upgrade to Stretch, gitweb no longer finds the configuration file
>> "gitweb_config.perl" in the current directory. However, "man gitweb" still
>> mentions this as one of the possible locations of the config file (and
>> indeed a useful one when using multiple instances of gitweb).
>>
>> It was probably broken by Perl dropping "." from the default search path
>> for security reasons.
>
> Indeed, perldelta(1) tells me that in 5.24.1 (and 5.26, etc),
>
>   Core modules and tools no longer search "." for optional modules
>
> gitweb.perl contains
>
>  sub read_config_file {
>          my $filename = shift;
>          return unless defined $filename;
>          # die if there are errors parsing config file
>          if (-e $filename) {
>                  do $filename;
>
> which implies an @INC search but it is silly --- as the "-e" test
> illustrates, this never intended to search @INC.
>
> Documentation says "If you are absolutely certain that you want your
> script to load and execute a file from the current directory, then use
> a ./ prefix".  We can do that, like so:
>
> diff --git i/gitweb/Makefile w/gitweb/Makefile
> index cd194d057f..3160b6cc5d 100644
> --- i/gitweb/Makefile
> +++ w/gitweb/Makefile
> @@ -18,7 +18,7 @@ RM ?= rm -f
>  INSTALL ?= install
>
>  # default configuration for gitweb
> -GITWEB_CONFIG = gitweb_config.perl
> +GITWEB_CONFIG = ./gitweb_config.perl
>  GITWEB_CONFIG_SYSTEM = /etc/gitweb.conf
>  GITWEB_CONFIG_COMMON = /etc/gitweb-common.conf
>  GITWEB_HOME_LINK_STR = projects
>
> but that does not help if someone overrides GITWEB_CONFIG, and besides,
> it would be nicer to avoid the possibility of an @INC search altogether.
> Another alternative would be to use
>
> 	local @INC = ('.');
>
> Would that be better?
>
> Advice from someone more versed than I am in perl would be very welcome
> (hence the cc to Ævar).

It seems most sensible to follow the ./FILE.pl advice per
https://metacpan.org/pod/distribution/perl/pod/perl5260delta.pod#Removal-of-the-current-directory-(%22.%22)-from-@INC

Just:

    local @INC = '.';
    do 'FILE.pl';

Would do the same thing, but seems like a more indirect way to do it if
all we want is ./ anyway. FWIW to be pedantically bug-compatible with
the old version (we should not do this) it's:

    local @INC = (@INC, ".");
    do 'FILE.pl';

I.e. before our behavior was implicitly to check whether we had a local
FILE.pl, then loop through all of @INC to see if we found it there, and
finally come back to the file we did the -e check for.