proc-macros used as build-depedencies and normal depedencies have features unified

[Baptistemontan]

Problem

If a package depends on a crate both as a dev-depedency and a normal depedency, and that crate pass feature flags to a macro, the features flags for the macro will be unified.

# workspace Cargo.toml
[workspace]
resolver = "2"
members = ["app", "common", "macros"]

[workspace.dependencies]
macros = { path = "./macros" }
common = { path = "./common" }

# app package Cargo.toml
[package]
name = "app"
version = "0.1.0"

[dependencies]
common = { workspace = true }

[build-dependencies]
common = { workspace = true, features = ["foo"] }

# common package Cargo.toml
[package]
name = "common"
version = "0.1.0"

[dependencies]
macros = { workspace = true }

[features]
default = []
foo = ["macros/foo"]

# macros package Cargo.toml
[package]
name = "macros"
version = "0.1.0"

[lib]
proc-macro = true

[features]
default = []
foo = ["macros/foo"]

When compiling the app package, the common package will have the "foo" feature enabled in the build.rs script (as expected), but will not during the normal build (as expected), BUT the macros package will have the "foo" feature enabled at both.

This create an issue when the macros package expect the common package to also have the feature enabled (to use some exported items for exemple).

Steps

No response

Possible Solution(s)

No response

Notes

No response

Version

cargo 1.86.0-nightly (2928e3273 2025-02-07)
release: 1.86.0-nightly
commit-hash: 2928e32734b04925ee51e1ae88bea9a83d2fd451
commit-date: 2025-02-07
host: x86_64-pc-windows-msvc
libgit2: 1.9.0 (sys:0.20.0 vendored)
libcurl: 8.9.0-DEV (sys:0.4.74+curl-8.9.0 vendored ssl:Schannel)
os: Windows 10.0.26100 (Windows 11 Professional) [64-bit]

[epage]

This sounds like a duplicate of #14415 and so I'm closing in favor of that. If there is a reason for us to keep this open separately, let us know! If so, please add a full reproduction case with instructions in how to observe the behavior.

[Baptistemontan]

Thanks, I couldn't find any related issue, it is indeed the same problem, sorry for opening this