如何防止通過多個依賴項鍊接到相同的本機庫？

Question

問題：我該如何解決（或修復）我的兩個依賴項鍊接到同一個庫的情況，但該庫無法鏈接兩次？這看起來像是一個通常可以通過共享庫解決的問題，但我不確定如何使用Rust進行處理。

詳情：

我使用一個數據庫的Nickel framework和rust-postgres提出一個web應用程序中生鏽。建設時，我得到了以下錯誤：

> cargo build 
native library `openssl` is being linked to by more than one package, and can only be linked to by one package 

    openssl-sys v0.3.3 (https://github.com/sfackler/rust-openssl.git#ee66da60) 
    openssl-sys v0.3.3 

通過Cargo.lock看，OpenSSL是通過HTTP引用（這是鎳的依賴）和防鏽的Postgres。

我Cargo.toml看起來是這樣的：

[package] 

name = "goodoldweb" 
version = "0.0.1" 
authors = ["..."] 

[dependencies.nickel] 
git="https://github.com/nickel-org/nickel.rs.git" 

[dependencies.postgres] 
git="https://github.com/sfackler/rust-postgres.git" 

下面是完整的Cargo.lock：

[root] 
name = "goodoldweb" 
version = "0.0.1" 
dependencies = [ 
"nickel 0.1.0 (git+https://github.com/nickel-org/nickel.rs.git)", 
"postgres 0.6.1 (git+https://github.com/sfackler/rust-postgres.git)", 
] 

[[package]] 
name = "byteorder" 
version = "0.2.4" 
source = "registry+https://github.com/rust-lang/crates.io-index" 

[[package]] 
name = "gcc" 
version = "0.1.7" 
source = "registry+https://github.com/rust-lang/crates.io-index" 

[[package]] 
name = "groupable" 
version = "0.1.0" 
source = "git+https://github.com/nickel-org/groupable-rs#efc8d769f611558f086322cd8d2d5ff53314e435" 

[[package]] 
name = "http" 
version = "0.1.0-pre" 
source = "git+https://github.com/nickel-org/rust-http.git#1997192b7662ee5bf3bf381bfd9e2aa70f85a545" 
dependencies = [ 
"openssl 0.3.3 (git+https://github.com/sfackler/rust-openssl.git)", 
"time 0.1.17 (git+https://github.com/rust-lang/time)", 
"url 0.2.18 (git+https://github.com/nickel-org/rust-url.git)", 
] 

[[package]] 
name = "libc" 
version = "0.1.2" 
source = "registry+https://github.com/rust-lang/crates.io-index" 

[[package]] 
name = "libressl-pnacl-sys" 
version = "2.1.4" 
source = "registry+https://github.com/rust-lang/crates.io-index" 
dependencies = [ 
"pnacl-build-helper 1.3.2 (registry+https://github.com/rust-lang/crates.io-index)", 
] 

[[package]] 
name = "log" 
version = "0.2.3" 
source = "registry+https://github.com/rust-lang/crates.io-index" 

[[package]] 
name = "matches" 
version = "0.1.2" 
source = "registry+https://github.com/rust-lang/crates.io-index" 

[[package]] 
name = "nickel" 
version = "0.1.0" 
source = "git+https://github.com/nickel-org/nickel.rs.git#8c2e6a9bdbce0a3ec53d559b86f5060ee1ea6c29" 
dependencies = [ 
"groupable 0.1.0 (git+https://github.com/nickel-org/groupable-rs)", 
"http 0.1.0-pre (git+https://github.com/nickel-org/rust-http.git)", 
"log 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)", 
"nickel_macros 0.0.1 (git+https://github.com/nickel-org/nickel.rs.git)", 
"plugin 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)", 
"regex 0.1.14 (registry+https://github.com/rust-lang/crates.io-index)", 
"regex_macros 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)", 
"rust-mustache 0.3.0 (git+https://github.com/nickel-org/rust-mustache.git)", 
"rustc-serialize 0.2.12 (registry+https://github.com/rust-lang/crates.io-index)", 
"time 0.1.17 (git+https://github.com/rust-lang/time)", 
"typemap 0.0.8 (registry+https://github.com/rust-lang/crates.io-index)", 
"url 0.2.18 (git+https://github.com/nickel-org/rust-url.git)", 
] 

[[package]] 
name = "nickel_macros" 
version = "0.0.1" 
source = "git+https://github.com/nickel-org/nickel.rs.git#8c2e6a9bdbce0a3ec53d559b86f5060ee1ea6c29" 

[[package]] 
name = "openssl" 
version = "0.3.3" 
source = "git+https://github.com/sfackler/rust-openssl.git#ee66da6060c57bc86906261ee3d684fac1fd05e4" 
dependencies = [ 
"openssl-sys 0.3.3 (git+https://github.com/sfackler/rust-openssl.git)", 
] 

[[package]] 
name = "openssl" 
version = "0.3.3" 
source = "registry+https://github.com/rust-lang/crates.io-index" 
dependencies = [ 
"openssl-sys 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)", 
] 

[[package]] 
name = "openssl-sys" 
version = "0.3.3" 
source = "git+https://github.com/sfackler/rust-openssl.git#ee66da6060c57bc86906261ee3d684fac1fd05e4" 
dependencies = [ 
"gcc 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)", 
"libressl-pnacl-sys 2.1.4 (registry+https://github.com/rust-lang/crates.io-index)", 
"pkg-config 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)", 
] 

[[package]] 
name = "openssl-sys" 
version = "0.3.3" 
source = "registry+https://github.com/rust-lang/crates.io-index" 
dependencies = [ 
"gcc 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)", 
"libressl-pnacl-sys 2.1.4 (registry+https://github.com/rust-lang/crates.io-index)", 
"pkg-config 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)", 
] 

[[package]] 
name = "phantom" 
version = "0.0.3" 
source = "registry+https://github.com/rust-lang/crates.io-index" 

[[package]] 
name = "phf" 
version = "0.6.6" 
source = "registry+https://github.com/rust-lang/crates.io-index" 
dependencies = [ 
"phf_shared 0.6.6 (registry+https://github.com/rust-lang/crates.io-index)", 
] 

[[package]] 
name = "phf_macros" 
version = "0.6.6" 
source = "registry+https://github.com/rust-lang/crates.io-index" 
dependencies = [ 
"phf_shared 0.6.6 (registry+https://github.com/rust-lang/crates.io-index)", 
"rand 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)", 
] 

[[package]] 
name = "phf_shared" 
version = "0.6.6" 
source = "registry+https://github.com/rust-lang/crates.io-index" 

[[package]] 
name = "pkg-config" 
version = "0.2.0" 
source = "registry+https://github.com/rust-lang/crates.io-index" 

[[package]] 
name = "plugin" 
version = "0.2.1" 
source = "registry+https://github.com/rust-lang/crates.io-index" 
dependencies = [ 
"typemap 0.0.8 (registry+https://github.com/rust-lang/crates.io-index)", 
] 

[[package]] 
name = "pnacl-build-helper" 
version = "1.3.2" 
source = "registry+https://github.com/rust-lang/crates.io-index" 

[[package]] 
name = "postgres" 
version = "0.6.1" 
source = "git+https://github.com/sfackler/rust-postgres.git#fe6ae0c63a6e5d66d2afb785605b7d89ec47062d" 
dependencies = [ 
"byteorder 0.2.4 (registry+https://github.com/rust-lang/crates.io-index)", 
"log 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)", 
"openssl 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)", 
"phf 0.6.6 (registry+https://github.com/rust-lang/crates.io-index)", 
"phf_macros 0.6.6 (registry+https://github.com/rust-lang/crates.io-index)", 
"rustc-serialize 0.2.12 (registry+https://github.com/rust-lang/crates.io-index)", 
"time 0.1.17 (registry+https://github.com/rust-lang/crates.io-index)", 
] 

[[package]] 
name = "rand" 
version = "0.1.2" 
source = "registry+https://github.com/rust-lang/crates.io-index" 
dependencies = [ 
"libc 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)", 
"log 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)", 
] 

[[package]] 
name = "regex" 
version = "0.1.14" 
source = "registry+https://github.com/rust-lang/crates.io-index" 

[[package]] 
name = "regex_macros" 
version = "0.1.8" 
source = "registry+https://github.com/rust-lang/crates.io-index" 
dependencies = [ 
"regex 0.1.14 (registry+https://github.com/rust-lang/crates.io-index)", 
] 

[[package]] 
name = "rust-mustache" 
version = "0.3.0" 
source = "git+https://github.com/nickel-org/rust-mustache.git#58ed857c88f8e5230913c382034601f37141b4ee" 
dependencies = [ 
"log 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)", 
"rustc-serialize 0.2.12 (registry+https://github.com/rust-lang/crates.io-index)", 
] 

[[package]] 
name = "rustc-serialize" 
version = "0.2.12" 
source = "registry+https://github.com/rust-lang/crates.io-index" 

[[package]] 
name = "time" 
version = "0.1.17" 
source = "git+https://github.com/rust-lang/time#0960d5e21b332088b04f62117514b0a02fd31259" 
dependencies = [ 
"gcc 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)", 
"libc 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)", 
] 

[[package]] 
name = "time" 
version = "0.1.17" 
source = "registry+https://github.com/rust-lang/crates.io-index" 
dependencies = [ 
"gcc 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)", 
"libc 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)", 
] 

[[package]] 
name = "typemap" 
version = "0.0.8" 
source = "registry+https://github.com/rust-lang/crates.io-index" 
dependencies = [ 
"phantom 0.0.3 (registry+https://github.com/rust-lang/crates.io-index)", 
"unsafe-any 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)", 
] 

[[package]] 
name = "unsafe-any" 
version = "0.2.2" 
source = "registry+https://github.com/rust-lang/crates.io-index" 

[[package]] 
name = "url" 
version = "0.2.18" 
source = "git+https://github.com/nickel-org/rust-url.git#5801582b307c16f759b5fe11dec71385af86180c" 
dependencies = [ 
"matches 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)", 
"rustc-serialize 0.2.12 (registry+https://github.com/rust-lang/crates.io-index)", 
] 

Answer 1

看來，罪魁禍首是事實，nickel-org's rust-http（是鎳的依賴）帶來sfackler/rust-openssl而不是crates.io上的「官方」openssl。不幸的是，rust-http回購沒有啓用問題，但我在鎳的主要回購中打開了一個：#139