cargo-script: error when dependent library uses `package.*.workspace` inheritance

[kleinesfilmroellchen]

Problem

If a cargo-script has a dependency on a local package that is located within a workspace, and that package inherits some package keys using the *.workspace = true mechanism, Cargo will not detect that the package is in its workspace correctly, and will claim that “workspace.* was not defined”.

Steps

Roughly minimal reproducer:

Top-level Cargo.toml:

[workspace]
members = ["dependency-lib"]

[workspace.package]
# could be any key(s) that are allowed here
edition = "2024"

dependency-lib/Cargo.toml:

[package]
name = "dependency-lib"
version = "0.1.0"
# !!!!!
edition.workspace = true

touch dependency-lib/src/lib.rs so that it’s a valid library.

Now create a script somewhere in the dependency tree (tested at top-level as well as in dependency-lib, which will need changes to the path):

#!/usr/bin/env -S cargo +nightly -Zscript
---
[dependencies]
# in this case the script is located within the "dependency-lib" directory
dependency-lib = { path = "." }
---
fn main() {}

Possible Solution(s)

For now, I’m using a separate bin package, which defeats some of the purpose of cargo-script.

Notes

Full output when running the script:

warning: `package.edition` is unspecified, defaulting to the latest edition (currently `2024`)
help: to pin the edition, run `cargo fix --manifest-path […]/script.rs`
error: failed to get `dependency-lib` as a dependency of package `script v0.0.0 ([…]/script.rs)`

Caused by:
  failed to load source for dependency `dependency-lib`

Caused by:
  unable to update […]/dependency-lib

Caused by:
  failed to parse manifest at `[…]/dependency-lib/Cargo.toml`

Caused by:
  error inheriting `edition` from workspace root manifest's `workspace.package.edition`

Caused by:
  `workspace.package.edition` was not defined

Version

cargo 1.97.0-nightly (a343accce 2026-05-08)
release: 1.97.0-nightly
commit-hash: a343accce8526b128adc517d33348573d22920a3
commit-date: 2026-05-08
host: x86_64-unknown-linux-gnu
libgit2: 1.9.2 (sys:0.20.4 vendored)
libcurl: 8.20.0-DEV (sys:0.4.88+curl-8.20.0 vendored ssl:OpenSSL/3.6.2)
ssl: OpenSSL 3.6.2 7 Apr 2026
os: Arch Linux Rolling Release [64-bit]

[kleinesfilmroellchen]

Part of #12207, previously discussed with @epage (see #12207 (comment) )

[epage]

This is likely caused by our cache for looking up the workspace root getting confused by two packages being in the same directory. We have other lookup issues in this code.

We might be able to workaround it by not injecting embedded manifests into the cache as workspace roots, unsure.

[kleinesfilmroellchen]

This is likely caused by our cache for looking up the workspace root getting confused by two packages being in the same directory. We have other lookup issues in this code.

As stated above, this happens both when I put it in the same directory as the dependency-lib Cargo.toml, as well as the top-level Cargo.toml.