[Mesa-dev] [PATCH 12/26] python: Fix unequality comparisons

[Dylan Baker]

Quoting Mathieu Bridon (2018-07-05 06:17:43)
> On Python 3, executing `foo != bar` will first try to call
> foo.__ne__(bar), and fallback on the opposite result of foo.__eq__(bar).
> 
> Python 2 does not do that.
> 
> As a result, those __eq__ methods were never called, when we were
> testing for inequality.
> 
> Expliclty adding the __ne__ methods fixes this issue, in a way that is
> compatible with both Python 2 and 3.
> 
> However, this means the __eq__ methods are now called when testing for
> `foo != None`, so they need to be guarded correctly.
> 
> Signed-off-by: Mathieu Bridon <bochecha at daitauha.fr>
> ---
>  src/amd/vulkan/vk_format_parse.py            | 6 ++++++
>  src/gallium/auxiliary/util/u_format_parse.py | 6 ++++++
>  src/mesa/main/format_parser.py               | 6 ++++++
>  3 files changed, 18 insertions(+)
> 
> diff --git a/src/amd/vulkan/vk_format_parse.py b/src/amd/vulkan/vk_format_parse.py
> index 00cf1adf5a..778eae61ba 100644
> --- a/src/amd/vulkan/vk_format_parse.py
> +++ b/src/amd/vulkan/vk_format_parse.py
> @@ -73,8 +73,14 @@ class Channel:
>          return s
>  
>      def __eq__(self, other):
> +        if other is None:
> +            return False
> +
>          return self.type == other.type and self.norm == other.norm and self.pure == other.pure and self.size == other.size and self.scaled == other.scaled
>  
> +    def __ne__(self, other):
> +        return not self.__eq__(other)

This can be written as "not (self == other)", right?

> +
>      def max(self):
>          '''Maximum representable number.'''
>          if self.type == FLOAT:
> diff --git a/src/gallium/auxiliary/util/u_format_parse.py b/src/gallium/auxiliary/util/u_format_parse.py
> index 315c771081..e60b317e08 100644
> --- a/src/gallium/auxiliary/util/u_format_parse.py
> +++ b/src/gallium/auxiliary/util/u_format_parse.py
> @@ -69,8 +69,14 @@ class Channel:
>          return s
>  
>      def __eq__(self, other):
> +        if other is None:
> +            return False
> +
>          return self.type == other.type and self.norm == other.norm and self.pure == other.pure and self.size == other.size
>  
> +    def __ne__(self, other):
> +        return not self.__eq__(other)
> +
>      def max(self):
>          '''Maximum representable number.'''
>          if self.type == FLOAT:
> diff --git a/src/mesa/main/format_parser.py b/src/mesa/main/format_parser.py
> index 3321ad33ff..c0d73c9d22 100644
> --- a/src/mesa/main/format_parser.py
> +++ b/src/mesa/main/format_parser.py
> @@ -61,8 +61,14 @@ class Channel:
>        return s
>  
>     def __eq__(self, other):
> +      if other is None:
> +         return False
> +
>        return self.type == other.type and self.norm == other.norm and self.size == other.size
>  
> +   def __ne__(self, other):
> +      return not self.__eq__(other)
> +
>     def max(self):
>        """Returns the maximum representable number."""
>        if self.type == FLOAT:
> -- 
> 2.17.1
> 
> _______________________________________________
> mesa-dev mailing list
> mesa-dev at lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/mesa-dev
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