[DRE-maint] Bug#859463: ruby-unf-ext FTBFS on ppc64el: unf/table.hh:13539:25: error: narrowing conversion of '-52' from 'int' to 'char' inside { } [-Wnarrowing]

[Niels Thykier]

On Mon, 03 Apr 2017 23:38:48 +0300 Adrian Bunk <bunk at debian.org> wrote:
> Source: ruby-unf-ext
> Version: 0.0.7.2-2
> Severity: serious
> 
> ruby-unf-ext FTBFS on ppc64el (originally reported by Frederic Bonnard):
> 
> ...
> unf/table.hh:13539:25: error: narrowing conversion of '-51' from 'int' to 'char' inside { } [-Wnarrowing]
> unf/table.hh:13539:25: error: narrowing conversion of '-123' from 'int' to 'char' inside { } [-Wnarrowing]
> unf/table.hh:13539:25: error: narrowing conversion of '-50' from 'int' to 'char' inside { } [-Wnarrowing]
> unf/table.hh:13539:25: error: narrowing conversion of '-105' from 'int' to 'char' inside { } [-Wnarrowing]
> unf/table.hh:13539:25: error: narrowing conversion of '-52' from 'int' to 'char' inside { } [-Wnarrowing]
> ...
> 
> 
> Complete log is attached.

This is caused by ppc64el having "char" being unsigned by default.
Beyond the table that needs to be converted/dealt with, there are about
20 -Wsign-conversion issues in the code that smells like they may cause
issues as well.

That said, a short term fix may be to revert:
https://github.com/knu/ruby-unf_ext/commit/1e2d2bc29798342ab2616eb3d74ea36c793a33e4

Thanks,
~Niels