Re: [PATCH for-4.14] golang/xenlight: sort cases in switch statement

[Ian Jackson <ian.jackson@citrix.com>]

Nick Rosbrook writes ("[PATCH for-4.14] golang/xenlight: sort cases in switch statement"):
> The xenlight_golang_union_from_C function iterates over a dict to
> construct a switch statement that marshals a C keyed union into a Go
> type. Because python does not guarantee dict ordering across all
> versions, this can result in the switch statement being generated in a
> different order depending on the version of python used. For example,
> running gengotypes.py with python2.7 and python3.6 will yield different
> orderings.
> 
> Iterate over sorted(cases.items()) rather than cases.items() to fix
> this.
> 
> This patch changes the ordering from what was previously checked-in, but
> running gengotypes.py with different versions of python will now yield
> the same result.
> 
> Signed-off-by: Nick Rosbrook <rosbrookn@ainfosec.com>
> ---
> Andrew reported this in [1], so I intend this as a build fix for 4.14.
> 
> [1] https://lists.xenproject.org/archives/html/xen-devel/2020-06/msg00881.html
> ---
>  tools/golang/xenlight/gengotypes.py  |  2 +-
>  tools/golang/xenlight/helpers.gen.go | 32 ++++++++++++++--------------
>  2 files changed, 17 insertions(+), 17 deletions(-)
> 
> diff --git a/tools/golang/xenlight/gengotypes.py b/tools/golang/xenlight/gengotypes.py
> index ecca59745f..557fecd07b 100644
> --- a/tools/golang/xenlight/gengotypes.py
> +++ b/tools/golang/xenlight/gengotypes.py
> @@ -379,7 +379,7 @@ def xenlight_golang_union_from_C(ty = None, union_name = '', struct_name = ''):
>  
>      # Create switch statement to determine which 'union element'
>      # to populate in the Go struct.
> -    for case_name, case_tuple in cases.items():
> +    for case_name, case_tuple in sorted(cases.items()):
>          (case_val, case_type) = case_tuple

This part

Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>

But I don't think I have the right golang tools to verify the
autogenerated code.  George, can you check that this patch is right,
and/or do the commit and rerun the generation ?

Obviously that needs to wait for a release ack.

Ian.