The Rust crate v7.2.1 covers the API of C library libzstd 1.5.6, but
fails to cover the API of libstds 1.5.7.

Building a project depending on rust-zstd-safe fails like this:

error[E0433]: failed to resolve: could not find `ZSTD_paramSwitch_e` in `zstd_sys`
    --> /build/atomic-data-rust-0.40.0+ds/debian/cargo_registry/zstd-safe-7.2.1/src/lib.rs:2081:22
     |
2081 |     Auto = zstd_sys::ZSTD_paramSwitch_e::ZSTD_ps_auto as u32,
     |                      ^^^^^^^^^^^^^^^^^^
     |                      |
     |                      could not find `ZSTD_paramSwitch_e` in `zstd_sys`
     |                      help: an enum with a similar name exists: `ZSTD_ParamSwitch_e`

error[E0433]: failed to resolve: could not find `ZSTD_paramSwitch_e` in `zstd_sys`
    --> /build/atomic-data-rust-0.40.0+ds/debian/cargo_registry/zstd-safe-7.2.1/src/lib.rs:2082:24
     |
2082 |     Enable = zstd_sys::ZSTD_paramSwitch_e::ZSTD_ps_enable as u32,
     |                        ^^^^^^^^^^^^^^^^^^
     |                        |
     |                        could not find `ZSTD_paramSwitch_e` in `zstd_sys`
     |                        help: an enum with a similar name exists: `ZSTD_ParamSwitch_e`

error[E0433]: failed to resolve: could not find `ZSTD_paramSwitch_e` in `zstd_sys`
    --> /build/atomic-data-rust-0.40.0+ds/debian/cargo_registry/zstd-safe-7.2.1/src/lib.rs:2083:25
     |
2083 |     Disable = zstd_sys::ZSTD_paramSwitch_e::ZSTD_ps_disable as u32,
     |                         ^^^^^^^^^^^^^^^^^^
     |                         |
     |                         could not find `ZSTD_paramSwitch_e` in `zstd_sys`
     |                         help: an enum with a similar name exists: `ZSTD_ParamSwitch_e`

For more information about this error, try `rustc --explain E0433`.
error: could not compile `zstd-safe` (lib) due to 3 previous errors

Upstream has fixed this in https://github.com/gyscos/zstd-rs/pull/324
which was included with crate v7.2.3.

 - Jonas
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Quoting Jonas Smedegaard (2025-08-06 22:22:34)

The failure occurs when building with the feature "experimental".

The package does not run the upstream testsuite during build, and
although they are run in debci (i.a. autopkgtests), failures are
ignored - and indeed the test for the feature "experimental" fails,
seeen e.g. at
https://ci.debian.net/packages/r/rust-zstd-safe/unstable/amd64/61950817/#L9091

 - Jonas