Hello, When using ‘guix package’, upon a substitute hash mismatch, all we see is something like this:
--8<---------------cut here---------------start------------->8--- Found valid signature for /gnu/store/cpw9yca1mcqhqfq450dr3rz2jzr95l69-glib-2.48.0 >From >https://mirror.hydra.gnu.org/nar/cpw9yca1mcqhqfq450dr3rz2jzr95l69-glib-2.48.0 Downloading cpw9yc...-glib-2.48.0 (13.5MiB installed)... glib-2.48.0 744KiB/s 00:04 | 2.9MiB transferred killing process 11821 guix system: error: build failed: some substitutes for the outputs of derivation `/gnu/store/lkvlm17z8qm1v6r4n5ja5vcmsp7d860i-graphviz-2.38.0.drv' failed (usually happens due to networking issues); try `--fallback' to build derivation from source --8<---------------cut here---------------end--------------->8--- The error message from build.cc: --8<---------------cut here---------------start------------->8--- if (expectedHash != actualHash) throw SubstError(format("hash mismatch in downloaded path `%1%': expected %2%, got %3%") % storePath % printHash(expectedHash) % printHash(actualHash)); --8<---------------cut here---------------end--------------->8--- … is only visible when we set-build-options #:print-build-trace? #t (like ‘guix build’ does, but ‘guix package’ and others do not.) The message should always be displayed, regardless of #:print-build-trace?. Ludo’.