Re: What’s next?

[Ludovic Courtès]

Ricardo Wurmus <address@hidden> skribis:

> Ludovic Courtès <address@hidden> writes:
>
>> Hello!
>>
>> Ricardo Wurmus <address@hidden> skribis:
>>
>>> Here are some other annoyances:
>>>
>>> * the verbosity of reporting hash mismatches.  You posted a neat little
>>>   change for that some time ago, but I cannot find it any more.
>>
>> Oh right, see attached.
>
> I think you forgot to attach it.

Oops.  Here we go:

modified   nix/libstore/build.cc
@@ -2449,8 +2449,11 @@ void DerivationGoal::registerOutputs()
             Hash h2 = recursive ? hashPath(ht, actualPath).first : 
hashFile(ht, actualPath);
             if (h != h2)
                 throw BuildError(
-                    format("output path `%1%' should have %2% hash `%3%', 
instead has `%4%'")
-                    % path % i->second.hashAlgo % printHash16or32(h) % 
printHash16or32(h2));
+                    format("%1% hash mismatch for output path `%2%'\n"
+                          "  expected: %3%\n"
+                          "  actual:   %4%")
+                    % i->second.hashAlgo % path
+                   % printHash16or32(h) % printHash16or32(h2));
         }
 
         /* Get rid of all weird permissions.  This also checks that
@@ -3096,7 +3099,9 @@ void SubstitutionGoal::finished()
             Hash expectedHash = parseHash16or32(hashType, 
string(expectedHashStr, n + 1));
             Hash actualHash = hashType == htSHA256 ? hash.first : 
hashPath(hashType, destPath).first;
             if (expectedHash != actualHash)
-                throw SubstError(format("hash mismatch in downloaded path 
`%1%': expected %2%, got %3%")
+                throw SubstError(format("hash mismatch in downloaded path 
`%1%'\n"
+                                       "  expected: %2%\n"
+                                       "  actual:   %3%")
                     % storePath % printHash(expectedHash) % 
printHash(actualHash));
         }

Should we apply it?

>> I agree with this direction, but we’ll have to work on concrete cases
>> here.  Bug reports of the form “when I do this I get a stack trace
>> instead of an error message” are welcome!
>
> Danny submitted bug #27100 for this with two examples.

Great.

Thanks,
Ludo’.