Unhelpfull error message on corrupted derivation "expected string 'D'" #447

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opened 2024-07-13 11:36:37 +00:00 by pr2502 · 1 comment

pr2502 commented

2024-07-13 11:36:37 +00:00

Describe the bug

When the nix store is corrupted in such a way that a derivation file (.drv) is empty the parsing fails with broken looking and not very helpful error message:

fetching path input 'path:/nix/store/dk2rpyb6ndvfbf19bkb2plcz5y3k8i5v-source'
error:
       … while evaluating 'strict' to select 'drvPath' on it
         at /builtin/derivation.nix:1:552:
       … while calling the 'derivationStrict' builtin
         at /builtin/derivation.nix:1:208:
       (stack trace truncated; use '--show-trace' to show the full trace)

       error: error parsing derivation '/nix/store/qw0v3wzkvbipjbvbba36f7i3zjqg7n3f-source.drv': error: expected string 'D'

Steps To Reproduce

create any derivation like

nix-repl> derivation { name = "expected-d-repro"; system = builtins.currentSystem; builder = "builder"; }
«derivation /nix/store/s1fiwaika47si98h0297sldnqqalyrx2-expected-d-repro.drv»

corrupt the derivation

$ sudo mount -o remount,rw /nix/store
$ sudo truncate -s0 /nix/store/s1fiwaika47si98h0297sldnqqalyrx2-expected-d-repro.drv

attempt to build the corrupted derivation

$ nix-build /nix/store/s1fiwaika47si98h0297sldnqqalyrx2-expected-d-repro.drv
error: error parsing derivation '/nix/store/s1fiwaika47si98h0297sldnqqalyrx2-expected-d-repro.drv': error: expected string 'D'

Expected behavior

I'd expect a bit more descriptive error message, probably a suggestion to run nix-store --verify-path <drvpath> and maybe even how to fix it? in this case that's nix-store --delete <drvpath> but I'm not sure if that's universally applicable. nix-store --repair-path <drvpath> definitely did not work in this case.

`nix --version` output

nix (Lix, like Nix) 2.91.0-dev-pre20240705-b6a08a2

## Describe the bug When the nix store is corrupted in such a way that a derivation file (.drv) is empty the parsing fails with broken looking and not very helpful error message: ``` fetching path input 'path:/nix/store/dk2rpyb6ndvfbf19bkb2plcz5y3k8i5v-source' error: … while evaluating 'strict' to select 'drvPath' on it at /builtin/derivation.nix:1:552: … while calling the 'derivationStrict' builtin at /builtin/derivation.nix:1:208: (stack trace truncated; use '--show-trace' to show the full trace) error: error parsing derivation '/nix/store/qw0v3wzkvbipjbvbba36f7i3zjqg7n3f-source.drv': error: expected string 'D' ``` ## Steps To Reproduce 1. create any derivation like ``` nix-repl> derivation { name = "expected-d-repro"; system = builtins.currentSystem; builder = "builder"; } «derivation /nix/store/s1fiwaika47si98h0297sldnqqalyrx2-expected-d-repro.drv» ``` 2. corrupt the derivation ``` $ sudo mount -o remount,rw /nix/store $ sudo truncate -s0 /nix/store/s1fiwaika47si98h0297sldnqqalyrx2-expected-d-repro.drv ``` 3. attempt to build the corrupted derivation ``` $ nix-build /nix/store/s1fiwaika47si98h0297sldnqqalyrx2-expected-d-repro.drv error: error parsing derivation '/nix/store/s1fiwaika47si98h0297sldnqqalyrx2-expected-d-repro.drv': error: expected string 'D' ``` ## Expected behavior I'd expect a bit more descriptive error message, probably a suggestion to run `nix-store --verify-path <drvpath>` and maybe even how to fix it? in this case that's `nix-store --delete <drvpath>` but I'm not sure if that's universally applicable. `nix-store --repair-path <drvpath>` definitely did not work in this case. ## `nix --version` output `nix (Lix, like Nix) 2.91.0-dev-pre20240705-b6a08a2`

pr2502 added the

bug

label

2024-07-13 11:36:37 +00:00

qyriad added the

Area/store

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2024-07-13 17:06:34 +00:00

raito added the

release-blocker

label

2025-11-18 02:57:34 +00:00

raito added the

E/easy

label

2025-11-26 21:14:02 +00:00

lix-bot commented

2025-11-30 13:05:20 +00:00

Member

This issue was mentioned on Gerrit on the following CLs:

commit message in cl/4665 ("libstore/store-api: offer more information about drv parsing errors")
commit message in cl/4664 ("libstore/derivations: expand error message for the first misparse")

This issue was mentioned on Gerrit on the following CLs: * commit message in [cl/4665](https://gerrit.lix.systems/c/lix/+/4665) ("libstore/store-api: offer more information about drv parsing errors") * commit message in [cl/4664](https://gerrit.lix.systems/c/lix/+/4664) ("libstore/derivations: expand error message for the first misparse")