[PATCH evolve-ext] evolve: improve error message if unstable changes are disallowed

[Pierre-Yves David]

On 11/23/2016 05:19 PM, Mateusz Kwapich wrote:
> Excerpts from Pulkit Goyal's message of 2016-11-23 21:06:29 +0530:
>> # HG changeset patch
>> # User Pulkit Goyal <7895pulkit at gmail.com>
>> # Date 1479915042 -19800
>> #      Wed Nov 23 21:00:42 2016 +0530
>> # Node ID 32083f1f0c67341e5b4c22e880b70ccc4e0fc088
>> # Parent  cb2bac3253fbd52894ffcb4719a148fe6a3da38b
>> evolve: improve error message if unstable changes are disallowed
>>
>> I saw a question on stackoverflow why evolve reports something like cannot
>> fold chain not ending with head. Even I was confused the first time about the
>> behavior. The error message can be improved to avoid confusion to people who
>> are unaware about the config in future.
>
> That sounds like a very useful information. It sucks that the errors
> have newlines in them. I think we can avoid it - see my inline comments.

Yet, improving that message is a good idea. As mateuz pointed, we avoid 
new line in error message:

   https://www.mercurial-scm.org/wiki/UIGuideline#error_message

In this case pointing to some help about the config would be a good idea 
(this might involve creating such help o:-) )

Thanks for finding it and working on this.

-- 
Pierre-Yves David