From 48e5fbe8eeddf9fbe1fca3c9ee0e5fd5ac1bafb0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?L=C3=A9o=20Gaspard?= <leo@gaspard.io>
Date: Mon, 13 Aug 2018 14:44:30 +0900
Subject: [PATCH 1/2] buildRustPackage: allow patches to fix Cargo.lock

---
 pkgs/build-support/rust/default.nix    | 5 +++++
 pkgs/build-support/rust/fetchcargo.nix | 6 +++---
 2 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/pkgs/build-support/rust/default.nix b/pkgs/build-support/rust/default.nix
index fb1d6e390ae..820989a7620 100644
--- a/pkgs/build-support/rust/default.nix
+++ b/pkgs/build-support/rust/default.nix
@@ -7,6 +7,8 @@ in
 { name, cargoSha256 ? "unset"
 , src ? null
 , srcs ? null
+, cargoPatches ? []
+, patches ? []
 , sourceRoot ? null
 , logLevel ? ""
 , buildInputs ? []
@@ -23,6 +25,7 @@ let
   cargoDeps = if cargoVendorDir == null
     then fetchcargo {
         inherit name src srcs sourceRoot cargoUpdateHook;
+        patches = cargoPatches;
         sha256 = cargoSha256;
       }
     else null;
@@ -44,6 +47,8 @@ in stdenv.mkDerivation (args // {
 
   buildInputs = [ cacert git rust.cargo rust.rustc ] ++ buildInputs;
 
+  patches = cargoPatches ++ patches;
+
   configurePhase = args.configurePhase or ''
     runHook preConfigure
     # noop
diff --git a/pkgs/build-support/rust/fetchcargo.nix b/pkgs/build-support/rust/fetchcargo.nix
index 42a3ac27cb5..2670ed52864 100644
--- a/pkgs/build-support/rust/fetchcargo.nix
+++ b/pkgs/build-support/rust/fetchcargo.nix
@@ -1,11 +1,11 @@
 { stdenv, cacert, git, rust, cargo-vendor }:
-{ name ? "cargo-deps", src, srcs, sourceRoot, sha256, cargoUpdateHook ? "" }:
+{ name ? "cargo-deps", src, srcs, patches, sourceRoot, sha256, cargoUpdateHook ? "" }:
 stdenv.mkDerivation {
   name = "${name}-vendor";
   nativeBuildInputs = [ cacert cargo-vendor git rust.cargo ];
-  inherit src srcs sourceRoot;
+  inherit src srcs patches sourceRoot;
 
-  phases = "unpackPhase installPhase";
+  phases = "unpackPhase patchPhase installPhase";
 
   installPhase = ''
     if [[ ! -f Cargo.lock ]]; then

From af960e5df9450664968d3392130e499fbaf1713f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?L=C3=A9o=20Gaspard?= <leo@gaspard.io>
Date: Tue, 14 Aug 2018 11:20:30 +0900
Subject: [PATCH 2/2] buildRustPackage: add documentation about cargoPatches

---
 doc/languages-frameworks/rust.section.md | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/doc/languages-frameworks/rust.section.md b/doc/languages-frameworks/rust.section.md
index b77c41e9b22..eec982d4c90 100644
--- a/doc/languages-frameworks/rust.section.md
+++ b/doc/languages-frameworks/rust.section.md
@@ -59,6 +59,11 @@ all crate sources of this package. Currently it is obtained by inserting a
 fake checksum into the expression and building the package once. The correct
 checksum can be then take from the failed build.
 
+When the `Cargo.lock`, provided by upstream, is not in sync with the
+`Cargo.toml`, it is possible to use `cargoPatches` to update it. All patches
+added in `cargoPatches` will also be prepended to the patches in `patches` at
+build-time.
+
 To install crates with nix there is also an experimental project called
 [nixcrates](https://github.com/fractalide/nixcrates).