Allow a git dependency to resolve for a registry dependency

[vincentdephily]

Problem

Dependencies sourced from git are not considered as valid candidates for "normal" dependencies.

Steps

1. Create a Cargo.toml with env_logger = "0.10.0" and log = "=0.4.15"
2. Run cargo update and cargo tree
3. As expected, there is a single copy of the log crate
4. Switch to log = {git = "https://github.com/rust-lang/log", tag = "0.4.15" }
5. Run cargo update and cargo tree
6. We now have two copies of the log crate

Possible Solution(s)

No response

Notes

Might be related to #6921

Version

cargo 1.73.0
release: 1.73.0
host: x86_64-unknown-linux-gnu
libgit2: 1.6.4 (sys:0.17.2 vendored)
libcurl: 8.4.0 (sys:0.4.65+curl-8.2.1 system ssl:rustls-ffi/0.10.0/rustls/0.21.0)
os: Gentoo Linux 2.14 [64-bit]

[ehuss]

Thanks for the report! This is intended behavior, since cargo treats crates from different sources as distinct.

The correct way to indicate that you want to replace a registry dependency with one from a git dependency is to use a [patch] table.

[vincentdephily]

This makes sense, thanks.