686120ee4a
This caused an absolute saga which I would not like anyone else to have to experience. Let's put in a laser targeted error message that diagnoses this exact problem. Fixes: https://git.lix.systems/lix-project/lix/issues/484 Change-Id: I2a79f04aeb4a1b67c10115e5e39501d958836298
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1.2 KiB
| synopsis | issues | cls | category | credits | ||
|---|---|---|---|---|---|---|
| Build failures caused by `allowSubstitutes = false` while being the wrong system now produce a decent error |
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Fixes | jade |
Nix allows derivations to set allowSubstitutes = false in order to force them to be built locally without querying substituters for them.
This is useful for derivations that are very fast to build (especially if they produce large output).
However, this can shoot you in the foot if the derivation has to be substituted such as if the derivation is for another architecture, which is what --always-allow-substitutes is for.
Perhaps such derivations that are known to be impossible to build locally should ignore allowSubstitutes (irrespective of remote builders) in the future, but this at least reports the failure and solution directly.
$ nix build -f fail.nix
error: a 'unicornsandrainbows-linux' with features {} is required to build '/nix/store/...-meow.drv', but I am a 'x86_64-linux' with features {...}
Hint: the failing derivation has allowSubstitutes set to false, forcing it to be built rather than substituted.
Passing --always-allow-substitutes to force substitution may resolve this failure if the path is available in a substituter.