Build failure in librespot-core 0.6.0 due to incompatible vergen-lib versions (E0277)

[brchn6]

Problem

Building spotify-dl (which depends on librespot 0.6.0) fails on a clean system due to a trait mismatch inside librespot-core’s build script.

Error:

error[E0277]: the trait bound vergen::feature::build::Build: vergen_lib::entries::Add is not satisfied

Rust reports that two different versions of vergen_lib are in the dependency graph.

Dependency Graph

cargo tree shows:

vergen-gitcl 1.0.8
├── vergen 9.1.0
│ └── vergen-lib 9.1.0
└── vergen-lib 0.1.6

So two different vergen-lib versions are compiled simultaneously:

• 0.1.6 (used by vergen-gitcl)
• 9.x (used by vergen)

This causes trait Add from vergen-lib 0.1.6 to differ from the same-named trait in vergen-lib 9.x, breaking the build script.

Why this happens

Cargo resolves vergen to the latest 9.x version, which now depends on vergen-lib 9.x, while vergen-gitcl still depends on vergen-lib 0.1.6.

This creates an incompatible trait implementation boundary.

Environment

Rust stable (1.90+)
Linux x86_64
Clean Cargo cache

Fix Options

One of:

• Pin vergen = "=9.0.6" which still uses vergen-lib 0.1.6
• Upgrade vergen-gitcl to a version compatible with vergen-lib 9.x
• Add explicit dependency unification in librespot-core

Expected

librespot-core should compile without requiring downstream projects to pin internal build dependencies.

This appears to be a dependency resolution break introduced by newer vergen releases.