[PATCH] Configure: introduced --without-libxslt

[Dmitry Volyntsev]

On 06.05.2023 16:12, Maxim Dounin wrote:
> Hello!
>
> On Fri, May 05, 2023 at 11:05:09PM -0700, Dmitry Volyntsev wrote:
>
>> # HG changeset patch
>> # User Dmitry Volyntsev <xeioex at nginx.com>
>> # Date 1683353037 25200
>> #      Fri May 05 23:03:57 2023 -0700
>> # Node ID 4891e0920d7c0e89def28694686e34294c69acf1
>> # Parent  b71e69247483631bd8fc79a47cc32b762625b1fb
>> Configure: introduced --without-libxslt.
>>
>> This allows to explicitly disable libxslt discovery by
>> nginx and nginx addons.
>>
>> diff --git a/auto/lib/conf b/auto/lib/conf
>> --- a/auto/lib/conf
>> +++ b/auto/lib/conf
>> @@ -29,8 +29,21 @@ if [ $USE_ZLIB = YES ]; then
>>       . auto/lib/zlib/conf
>>   fi
>>   
>> -if [ $USE_LIBXSLT != NO ]; then
>> +if [ $USE_LIBXSLT != NO -a $USE_LIBXSLT != DISABLED ]; then
>>       . auto/lib/libxslt/conf
>> +
>> +else
>> +    if [ $USE_LIBXSLT = DISABLED -a $HTTP = YES -a $HTTP_XSLT = YES ]; then
>> +
>> +cat << END
>> +
>> +$0: error: the HTTP ngx_http_xslt_module requires the libxslt library.
>> +You can either disable the module by using --without-http_xslt_module
>> +option or you have to enable the libxslt support.
>> +
>> +END
>> +        exit 1
>> +    fi
>>   fi
>>   
>>   if [ $USE_LIBGD != NO ]; then
>> diff --git a/auto/modules b/auto/modules
>> --- a/auto/modules
>> +++ b/auto/modules
>> @@ -277,7 +277,7 @@ if [ $HTTP = YES ]; then
>>           . auto/module
>>       fi
>>   
>> -    if [ $HTTP_XSLT != NO ]; then
>> +    if [ $HTTP_XSLT != NO -a $USE_LIBXSLT != DISABLED ]; then
>>           ngx_module_name=ngx_http_xslt_filter_module
>>           ngx_module_incs=
>>           ngx_module_deps=
>> diff --git a/auto/options b/auto/options
>> --- a/auto/options
>> +++ b/auto/options
>> @@ -363,6 +363,8 @@ use the \"--with-mail_ssl_module\" optio
>>           --with-openssl=*)                OPENSSL="$value"           ;;
>>           --with-openssl-opt=*)            OPENSSL_OPT="$value"       ;;
>>   
>> +        --without-libxslt)               USE_LIBXSLT=DISABLED       ;;
>> +
>>           --with-md5=*)
>>               NGX_POST_CONF_MSG="$NGX_POST_CONF_MSG
>>   $0: warning: the \"--with-md5\" option is deprecated"
> The only "without" configure option for libraries we use is
> "--without-pcre", and it is disables PCRE library usage in the
> nginx core (notably, regular expressions in server names and
> locations).
>
> In contrast, the XSLT library is only used by the xslt filter
> module, and the natural way to disable its usage is to don't
> enable the module.  Similarly, OpenSSL, zlib, GD, and GeoIP
> libraries are enabled by the corresponding modules, and not
> enabled when the modules are not enabled.
>
> It is not clear why XSLT should be different, and how this is
> expected to be used.

That is correct that XSLT library is only used for xslt filter.
Nevertheless LIBXSLT is supported in ngx_module_libs for 3rd-party
nginx modules, so for XSLT there are may be other uses outside of
nginx core. Unlike OPENSSL and ZLIB which are essential parts of any
modern nginx build, LIBXSLT is less commonly used and users
sometimes want to disable LIBXSLT altogether.

What is the suggested way for a user to build 3rd-party module when
he/she wants to specifically disable a part which needs LIBXSLT?

Alternatively there can be a way for nginx user building nginx to
somehow signal to a 3rd-party module configure script what he/she wants.


>