How to Fix ClickHouse Rust Client Dependency Conflicts with Cargo Links

Problem Description

ClickHouse has two well‑maintained native Rust clients: clickhouse-rs (TCP) and clickhouse.rs (HTTP). Each works fine alone, but adding both to the same Cargo project triggers a build error.

Dependencies

<code># clickhouse http
clickhouse = { git = "https://github.com/loyd/clickhouse.rs", features = ["test-util"] }

# clickhouse tcp
clickhouse-rs = { git = "https://github.com/suharev7/clickhouse-rs", features = ["default"] }
</code>

Error Message

<code>Blocking waiting for file lock on package cache
Updating git repository `https://github.com/suharev7/clickhouse-rs`
Updating crates.io index
error: failed to select a version for `clickhouse-rs-cityhash-sys`.
  ... required by package `clickhouse-rs v1.0.0-alpha.1`
  ... which satisfies git dependency `clickhouse-rs`
versions that meet the requirements `^0.1.2` are: 0.1.2

the package `clickhouse-rs-cityhash-sys` links to the native library `clickhouse-rs`, but it conflicts with a previous package which links to `clickhouse-rs` as well:
Only one package in the dependency graph may specify the same links value.
Try to adjust your dependencies so that only one package uses the links = 'clickhouse-rs-cityhash-sys' value.
</code>

Root Cause

The conflict originates from the

clickhouse-rs-cityhash-sys

crate, which is referenced differently by the two clients.

clickhouse.rs

pulls it from

crates.io

using a normal version entry, while

clickhouse-rs

includes it as a local path dependency.

<code># clickhouse.rs (crates.io)
clickhouse-rs-cityhash-sys = { version = "0.1.2", optional = true }
</code>

<code># clickhouse-rs (local)
[dependencies.clickhouse-rs-cityhash-sys]
path = "clickhouse-rs-cityhash-sys"
version = "0.1.2"
</code>

Attempted Workspace Isolation

Creating a Cargo workspace with separate libraries (

ck_http

and

ck_tcp

) and moving each client into its own crate did not eliminate the conflict, because the

links

field is still duplicated in the dependency graph.

Solution

Inspecting

clickhouse-rs-cityhash-sys/Cargo.toml

reveals a

links = "clickhouse-rs"

entry. Changing this value to a unique name (e.g.,

links = "ck-rs-cityhash-sys"

) removes the duplication and the project builds successfully.

Understanding the links Field

The

links

field specifies the name of the native library that Cargo will link to. Only one package in the entire dependency graph may declare the same

links

name, ensuring a single copy of a native library in the final binary.

Conclusion

Renaming the

links

identifier in the conflicting native crate resolves the Cargo dependency conflict when using both ClickHouse Rust clients together. The full sample repository is available at https://github.com/jiashiwen/ck_dependency_conflict_sample for further experimentation.