Re: downloading a tarball

[Ludovic Courtès]

Hartmut Goebel <address@hidden> skribis:

> Am 24.03.2017 um 14:14 schrieb Tobias Geerinckx-Rice:
>>> > HTH - speaking from experience making the same mistake here..
>> I suspect most people have. The message isn't as clear as it could be.
>
> Either way round the message is hard to read: squezzed between many
> other message, no line-break and arguable wording. IMHO this should be
> improved to empower more people.

Yeah I agree.

What about this (patch below)?

--8<---------------cut here---------------start------------->8---
@ build-started 
/gnu/store/0rn80kgcbc90hfl2vl54adci7675fwb7-idutils-4.6.tar.xz.drv - 
x86_64-linux 
/var/log/guix/drvs/0r//n80kgcbc90hfl2vl54adci7675fwb7-idutils-4.6.tar.xz.drv.bz2

Starting download of 
/gnu/store/si0rm701sqmi3w69k2b2yzar4p99j66k-idutils-4.6.tar.xz
>From http://ftpmirror.gnu.org/idutils/idutils-4.6.tar.xz...
following redirection to 
`http://mirror.ibcp.fr/pub/gnu/idutils/idutils-4.6.tar.xz'...
 idutils-4.6.tar.xz  978KiB         743KiB/s 00:01 [####################] 100.0%
sha256 hash mismatch for output path 
`/gnu/store/si0rm701sqmi3w69k2b2yzar4p99j66k-idutils-4.6.tar.xz'
  expected: 1hmai3422iaqnp34kkzxdnywl7n7pvlxp11vrw66ybxn9wxg90c2
  actual:   1hmai3422iaqnp34kkzxdnywl7n7pvlxp11vrw66ybxn9wxg90c1
@ build-failed 
/gnu/store/0rn80kgcbc90hfl2vl54adci7675fwb7-idutils-4.6.tar.xz.drv - 1 sha256 
hash mismatch for output path 
`/gnu/store/si0rm701sqmi3w69k2b2yzar4p99j66k-idutils-4.6.tar.xz'
  expected: 1hmai3422iaqnp34kkzxdnywl7n7pvlxp11vrw66ybxn9wxg90c2
  actual:   1hmai3422iaqnp34kkzxdnywl7n7pvlxp11vrw66ybxn9wxg90c1
cannot build derivation 
`/gnu/store/kk172bqfx6ya7w62xm1vmr2c9iyq6cpy-idutils-4.6.tar.xz.drv': 1 
dependencies couldn't be built
guix build: error: build failed: build of 
`/gnu/store/kk172bqfx6ya7w62xm1vmr2c9iyq6cpy-idutils-4.6.tar.xz.drv' failed
--8<---------------cut here---------------end--------------->8---

(Here ‘guix build’ repeats the error message because of
#:print-build-trace, which is #true in ‘guix build’.)

Probably not optimal but hopefully an improvement.

Thanks,
Ludo’.

diff --git a/nix/libstore/build.cc b/nix/libstore/build.cc
index 9b7bb5391..a93095dd1 100644
--- a/nix/libstore/build.cc
+++ b/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));
         }