vendored deps have wrong versions

[ldicarlo]

Hello,
Thank you for this project, I use it daily.

I am stumbling on something that I don't understand

I have a flake, using crane and fenix, in a cargo workspace. All the code is here.

To be able to nix build it, I had to add the following dependencies:

rustc-literal-escaper = "=0.0.4"
cfg-if = "=1.0.1"
hashbrown = "=0.15.4"
rustc-demangle = "=0.1.25"
dlmalloc = "=0.2.9"
libc = "=0.2.174"
r-efi-alloc = "2.1.0"
fortanix-sgx-abi = "=0.5.0"
getopts = "=0.2.23"
unwinding = "=0.2.7"
unicode-width = "=0.2.1"
gimli = "=0.32.0"

which, none of them is required when using cargo build, but all of them are needed when using nix build.

I have no idea if the problem comes from my configuration of

• crane
• fenix
• rust-gpu git dependency that I have in it

but removing any dependency yields:

       Last 25 log lines:
       > decompressing cargo artifacts from /nix/store/vygs7c0lna91w82kvi16xwgy5zcv55cc-unkr-deps-0.1.3/target.tar.zst to target
       > Running phase: updateAutotoolsGnuConfigScriptsPhase
       > Running phase: configurePhase
       > will append /build/source/.cargo-home/config.toml with contents of /nix/store/ys4hgmzbz4bp3ys3agkjgm69gx312wfi-vendor-cargo-deps/config.toml
       > default configurePhase, nothing to do
       > Running phase: buildPhase
       > +++ command cargo --version
       > cargo 1.90.0-nightly (930b4f62c 2025-06-28)
       > +++ command cargo build --release --message-format json-render-diagnostics -p unkr
       >    Compiling unkr v0.1.3 (/build/source/unkr)
       > error: failed to run custom build command for `unkr v0.1.3 (/build/source/unkr)`
       >
       > Caused by:
       >   process didn't exit successfully: `/build/source/target/release/build/unkr-f48503fa9859bc16/build-script-build` (exit status: 1)
       >   --- stdout
       >   cargo:rerun-if-env-changed=RUSTGPU_CODEGEN_ARGS
       >   cargo:rerun-if-env-changed=RUSTGPU_RUSTFLAGS
       >   cargo:rerun-if-env-changed=RUSTGPU_CARGOFLAGS
       >
       >   --- stderr
       >   error: no matching package named `rustc-literal-escaper` found
       >   location searched: directory source `/nix/store/ys4hgmzbz4bp3ys3agkjgm69gx312wfi-vendor-cargo-deps/c19b7c6f923b580ac259164a89f2577984ad5ab09ee9d583b888f934adbbe8d0` (which is replacing registry `crates-io`)
       >   required by package `proc_macro v0.0.0 (/nix/store/9f6as24lbw69b6xsdimmwz6nbkamsh6r-rust-nightly-with-components-2025-06-30/lib/rustlib/src/rust/library/proc_macro)`
       >       ... which satisfies path dependency `proc_macro` (locked to 0.0.0) of package `sysroot v0.0.0 (/nix/store/9f6as24lbw69b6xsdimmwz6nbkamsh6r-rust-nightly-with-components-2025-06-30/lib/rustlib/src/rust/library/sysroot)`
       >   Error: BuildFailed

and not fixing the dependency (removing the equals sign) yields:

       > Running phase: configurePhase
       > will append /build/source/.cargo-home/config.toml with contents of /nix/store/hg4li334w1bgk2md92214968c91jc5fw-vendor-cargo-deps/config.toml
       > default configurePhase, nothing to do
       > Running phase: buildPhase
       > +++ command cargo --version
       > cargo 1.90.0-nightly (930b4f62c 2025-06-28)
       > +++ command cargo build --release --message-format json-render-diagnostics -p unkr
       >    Compiling unkr v0.1.3 (/build/source/unkr)
       > error: failed to run custom build command for `unkr v0.1.3 (/build/source/unkr)`
       >
       > Caused by:
       >   process didn't exit successfully: `/build/source/target/release/build/unkr-f48503fa9859bc16/build-script-build` (exit status: 1)
       >   --- stdout
       >   cargo:rerun-if-env-changed=RUSTGPU_CODEGEN_ARGS
       >   cargo:rerun-if-env-changed=RUSTGPU_RUSTFLAGS
       >   cargo:rerun-if-env-changed=RUSTGPU_CARGOFLAGS
       >
       >   --- stderr
       >   error: failed to select a version for the requirement `libc = "^0.2.172"` (locked to 0.2.174)
       >   candidate versions found which didn't match: 0.2.178
       >   location searched: directory source `/nix/store/hg4li334w1bgk2md92214968c91jc5fw-vendor-cargo-deps/c19b7c6f923b580ac259164a89f2577984ad5ab09ee9d583b888f934adbbe8d0` (which is replacing registry `crates-io`)
       >   required by package `std v0.0.0 (/nix/store/9f6as24lbw69b6xsdimmwz6nbkamsh6r-rust-nightly-with-components-2025-06-30/lib/rustlib/src/rust/library/std)`
       >       ... which satisfies path dependency `std` (locked to 0.0.0) of package `sysroot v0.0.0 (/nix/store/9f6as24lbw69b6xsdimmwz6nbkamsh6r-rust-nightly-with-components-2025-06-30/lib/rustlib/src/rust/library/sysroot)`
       >   perhaps a crate was updated and forgotten to be re-vendored?
       >   Error: BuildFailed

Do you have any idea where this comes from?
I suspect the presence of the build.rs may be part of the problem.

Thank you

[ipetkov]

Hi @ldicarlo ! Is your Cargo.lock file up to date? Typically when adding or removing dependencies you should see changes to Cargo.lock after you've run something like cargo build or cargo clippy or even cargo update.

Try running one of those commands and then commit the changes to Cargo.lock and see if that makes the issue go away!

[ipetkov]

Oh actually it looks like the dependencies you listed actually need to go under [build-dependencies] moving them there seems to compile for me

[ldicarlo]

So my lock file should be up to date because I always run cargo build && nix build actually. But what I wonder is why do I even need to add those dependencies in the Cargo.toml file when running with nix while running with cargo build does not require them?

[ipetkov]

Have you tried moving the above dependencies under [build-dependencies] and see if that helps?

I'm not too familiar with how your builds work, but I'm wondering if builds outside of nix happen to reuse the cargo crate cache but which doesn't exist in a sandboxed nix build and why it fails there

[ldicarlo]

I tried, and I keep having the same issues. I'd expect fenix and crane to create a new derivation of the "vendored dependencies" and this to be the "offline" crates.io for the build. But It seems the versions are not the same in the vendored folder as expected by the Cargo.lock file

[ipetkov]

Here's what I tried:

Prep:

git clone https://github.com/ldicarlo/unkr.git
git checkout c8afc40bd9611f0468ff610df2ea26d9d64a53c4

git apply <<EOF
diff --git a/unkr/Cargo.toml b/unkr/Cargo.toml
index a101086..6be7885 100644
--- a/unkr/Cargo.toml
+++ b/unkr/Cargo.toml
@@ -30,21 +30,6 @@ bytemuck = { version = "1.7", features = [
 ] }
 
 png = "0.18"
-# fixed deps
-rustc-literal-escaper = "=0.0.4"
-cfg-if = "=1.0.1"
-hashbrown = "=0.15.4"
-rustc-demangle = "=0.1.25"
-dlmalloc = "=0.2.9"
-libc = "=0.2.174"
-r-efi-alloc = "2.1.0"
-fortanix-sgx-abi = "=0.5.0"
-getopts = "=0.2.23"
-unwinding = "=0.2.7"
-unicode-width = "=0.2.1"
-gimli = "=0.32.0"
-# spirv-builder = { workspace = true }
-# spirv-std = { workspace = true }
 
 [dev-dependencies]
 pprof = { version = "0.15", features = ["flamegraph", "criterion"] }
EOF
cargo generate-lockfile
nix build .# -L

Fails with (i.e. reproduces the problem you are describing):

error: builder for '/nix/store/0i84kcpw86r58ss44fbh5gsbdmzdi1qf-unkr-0.1.3.drv' failed with exit code 101;
       last 25 log lines:
       > decompressing cargo artifacts from /nix/store/8ldr4wdzahly1nyxaly53aiyz23ix05l-unkr-deps-0.1.3/target.tar.zst to target
       > Running phase: updateAutotoolsGnuConfigScriptsPhase
       > Running phase: configurePhase
       > will append /build/source/.cargo-home/config.toml with contents of /nix/store/c72xkpqkam3h2garyalk4jjxr5f4fayw-vendor-cargo-deps/config.toml
       > default configurePhase, nothing to do
       > Running phase: buildPhase
       > +++ command cargo --version
       > cargo 1.90.0-nightly (930b4f62c 2025-06-28)
       > +++ command cargo build --release --message-format json-render-diagnostics -p unkr
       >    Compiling unkr v0.1.3 (/build/source/unkr)
       > error: failed to run custom build command for `unkr v0.1.3 (/build/source/unkr)`
       >
       > Caused by:
       >   process didn't exit successfully: `/build/source/target/release/build/unkr-e324e34d597a20d6/build-script-build` (exit status: 1)
       >   --- stdout
       >   cargo:rerun-if-env-changed=RUSTGPU_CODEGEN_ARGS
       >   cargo:rerun-if-env-changed=RUSTGPU_RUSTFLAGS
       >   cargo:rerun-if-env-changed=RUSTGPU_CARGOFLAGS
       >
       >   --- stderr
       >   error: no matching package named `rustc-literal-escaper` found
       >   location searched: directory source `/nix/store/c72xkpqkam3h2garyalk4jjxr5f4fayw-vendor-cargo-deps/c19b7c6f923b580ac259164a89f2577984ad5ab09ee9d583b888f934adbbe8d0` (which is replacing registry `crates-io`)
       >   required by package `proc_macro v0.0.0 (/nix/store/9f6as24lbw69b6xsdimmwz6nbkamsh6r-rust-nightly-with-components-2025-06-30/lib/rustlib/src/rust/library/proc_macro)`
       >       ... which satisfies path dependency `proc_macro` (locked to 0.0.0) of package `sysroot v0.0.0 (/nix/store/9f6as24lbw69b6xsdimmwz6nbkamsh6r-rust-nightly-with-components-2025-06-30/lib/rustlib/src/rust/library/sysroot)`
       >   Error: BuildFailed
       For full logs, run 'nix log /nix/store/0i84kcpw86r58ss44fbh5gsbdmzdi1qf-unkr-0.1.3.drv'.

---

Here's the same but with moving the listed dependencies under [build-dependencies

git checkout .
git apply <<EOF
diff --git a/unkr/Cargo.toml b/unkr/Cargo.toml
index a101086..f8b952b 100644
--- a/unkr/Cargo.toml
+++ b/unkr/Cargo.toml
@@ -30,6 +30,15 @@ bytemuck = { version = "1.7", features = [
 ] }
 
 png = "0.18"
+[dev-dependencies]
+pprof = { version = "0.15", features = ["flamegraph", "criterion"] }
+criterion = { version = "0.8", features = ["html_reports"] }
+pretty_assertions = "1.4.0"
+# spirv-builder = { workspace = true }
+
+[build-dependencies]
+spirv-builder = { workspace = true }
+# spirv-std = { workspace = true }
 # fixed deps
 rustc-literal-escaper = "=0.0.4"
 cfg-if = "=1.0.1"
@@ -46,15 +55,6 @@ gimli = "=0.32.0"
 # spirv-builder = { workspace = true }
 # spirv-std = { workspace = true }
 
-[dev-dependencies]
-pprof = { version = "0.15", features = ["flamegraph", "criterion"] }
-criterion = { version = "0.8", features = ["html_reports"] }
-pretty_assertions = "1.4.0"
-# spirv-builder = { workspace = true }
-
-[build-dependencies]
-spirv-builder = { workspace = true }
-# spirv-std = { workspace = true }
 
 [[bench]]
 name = "benchmark"
EOF
cargo generate-lockfile
nix build .# -L

This seems to build fine