On 11/11/2017 at 09:05 Chris Marusich writes:
> myglc2 <myg...@gmail.com> writes:
>
>> On 11/10/2017 at 15:30 Chris Marusich writes:
>>
>>> Hi Leo,
>>>
>>> Leo Famulari <l...@famulari.name> writes:
>>>
>>>> Substition is considered to fail when Guix is expecting a substitute but
>>>> the server returns 404, 504, or some other unexpected problem occurs. It
>>>> is not considered to fail if the server initially reports that no
>>>> substitute is available.
>>
>> Hi Leo, this is a wonderful clarification of behavior that has confused
>> me for 1.5 years!
>>>
>>> Thank you for the clarification. This is what I did not understand. I
>>> read the manual and got the impression that when --fallback has not been
>>> given, if a given substitute cannot be found (regardless of whether or
>>> not a substitute server claimed to provide one), then Guix will not
>>> build it. I see now that my understanding was mistaken.
>>
>> I had this mistaken impression too.
>>>
>>> I've attached a patch which tries to clarify this in the manual. What
>>> do you think of it?
>>
>> Hey Chris,
>>
>> How about saying what Leo said right up front in the substitutes
>> section. This allows the --fallback addition to be more brief.
>>
>> Rough draft below.
>>
>> WDYT? - George
>>
>> 1 file changed, 9 insertions(+), 2 deletions(-)
>> doc/guix.texi | 11 +++++++++--
>>
>> modified doc/guix.texi
>> @@ -2120,6 +2120,13 @@ server. We call these pre-built items
>> @dfn{substitutes}---they are
>> substitutes for local build results. In many cases, downloading a
>> substitute is much faster than building things locally.
>>
>> +When substitutes are enabled (the default) and a substitute is not
>> +available the build will take place locally. If a substitute is
>> +available but substitution fails, e.g., the substitute server returns
>> +404, 504, times out, or some other unexpected problem occurs, guix stops
>> +and reports an error unless --fallback or --keep-going options are
>> +specified.
>> +
>> Substitutes can be anything resulting from a derivation build
>> (@pxref{Derivations}). Of course, in the common case, they are
>> pre-built package binaries, but source tarballs, for instance, which
>> @@ -5192,8 +5199,8 @@ derivations has failed.
>> Do not build the derivations.
>>
>> @item --fallback
>> -When substituting a pre-built binary fails, fall back to building
>> -packages locally.
>> +Attempt to build locally instead of issuing an error when substitutes
>> +are enabled and the substitution of a pre-built binary fails.
>>
>> @item --substitute-urls=@var{urls}
>> @anchor{client-substitute-urls}
>
> I think I like the way you wrote it better. I'm fine with that. I was
> hoping not to add to the already-voluminous paragraphs about Substitutes
> at the top of section 3.3, but honestly as long as this info is in the
> manual, I'm happy.
I agree w/you Substitutes is overwhelming ;-)
Meanwhile, so will you submit the patch, or do you want me to?
TIA - George
