Re: Compilation errors when using extended GCC warnings

[Eric Blake]

On 03/29/2013 04:27 PM, Assaf Gordon wrote:
> Hello,
> 
> I'm trying to add "gnulib" to a new project.
> My project enables gcc's "-Wswitch-enum -Wswitch-default -Werror" settings.

In general, gnulib does NOT try to cater to all possible gcc warnings.
You may want to take the approach that coreutils and several other
projects have taken, of using a strong set of warnings for your own
code, and a smaller set of warnings on gnulib code, so that use of
-Werror doesn't trip over places where gnulib's coding styles aren't as
strict as what you want in your own code.

> When adding some gnulib modules, compilation fails.
> 
> When adding the "propername" module, I get the following error:
> ===
> unistr/u8-uctomb-aux.c: In function 'u8_uctomb_aux':
> unistr/u8-uctomb-aux.c:57:3: error: switch missing default case 
> [-Werror=switch-default]

Not sure if Bruno wants to adjust code to work around this.

> ===
> 
> When adding the "quote" module, I get the following errors:
> ===
> quotearg.c: In function 'quotearg_buffer_restyled':
> quotearg.c:389:11: error: enumeration value 'literal_quoting_style' not 
> handled in switch [-Werror=switch-enum]
> quotearg.c:389:11: error: enumeration value 'shell_quoting_style' not handled 
> in switch [-Werror=switch-enum]
> quotearg.c:389:11: error: enumeration value 'c_maybe_quoting_style' not 
> handled in switch [-Werror=switch-enum]
> quotearg.c:389:11: error: enumeration value 'escape_quoting_style' not 
> handled in switch [-Werror=switch-enum]
> quotearg.c:389:11: error: enumeration value 'locale_quoting_style' not 
> handled in switch [-Werror=switch-enum]
> quotearg.c:389:11: error: enumeration value 'clocale_quoting_style' not 
> handled in switch [-Werror=switch-enum]
> quotearg.c:389:11: error: enumeration value 'custom_quoting_style' not 
> handled in switch [-Werror=switch-enum]

Blah.  There's already a default label, precisely because we don't need
to do anything for all these other enum values.  I'm reluctant to add to
the code base just to silence an over-strict compiler warning.

Another option is that you can use a local patch, so that when
gnulib-tool is run on your project, you patch files locally to meet your
coding standards, even though upstream gnulib is reluctant to make those
changes.

> 
> Please advise, if this is a configuration error on my part, or a known 
> problem, or simply gnulib can't be used with GCC's extra warnings.

The latter.

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

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