rustPlatform.buildRustPackage: support direct use of Cargo.lock

This change introduces the cargoLock argument to buildRustPackage,
which can be used in place of cargo{Sha256,Hash} or cargoVendorDir. It
uses the importCargoLock function to build the vendor
directory. Differences compared to cargo{Sha256,Hash}:

- Requires a Cargo.lock file.
- Does not require a Cargo hash.
- Retrieves all dependencies as fixed-output derivations.

This makes buildRustPackage much easier to use as part of a Rust
project, since it does not require updating cargo{Sha256,Hash} for
every change to the lock file.

1 files changed, 15 insertions, 10 deletions

diff --git a/pkgs/build-support/rust/default.nix b/pkgs/build-support/rust/default.nix
index ff9ca642daa..711276116a6 100644
--- a/pkgs/build-support/rust/default.nix
+++ b/pkgs/build-support/rust/default.nix
@@ -7,6 +7,7 @@
 , cargoInstallHook
 , cargoSetupHook
 , fetchCargoTarball
+, importCargoLock
 , runCommandNoCC
 , rustPlatform
 , callPackage
@@ -41,6 +42,7 @@
 , cargoDepsHook ? ""
 , buildType ? "release"
 , meta ? {}
+, cargoLock ? null
 , cargoVendorDir ? null
 , checkType ? buildType
 , depsExtraArgs ? {}
@@ -55,19 +57,22 @@
 , buildAndTestSubdir ? null
 , ... } @ args:
 
-assert cargoVendorDir == null -> !(cargoSha256 == "" && cargoHash == "");
+assert cargoVendorDir == null && cargoLock == null -> cargoSha256 == "" && cargoHash == ""
+  -> throw "cargoSha256, cargoHash, cargoVendorDir, or cargoLock must be set";
 assert buildType == "release" || buildType == "debug";
 
 let
 
-  cargoDeps = if cargoVendorDir == null
-    then fetchCargoTarball ({
-        inherit src srcs sourceRoot unpackPhase cargoUpdateHook;
-        name = cargoDepsName;
-        hash = cargoHash;
-        patches = cargoPatches;
-        sha256 = cargoSha256;
-      } // depsExtraArgs)
+  cargoDeps =
+    if cargoVendorDir == null
+    then if cargoLock != null then importCargoLock cargoLock
+    else fetchCargoTarball ({
+      inherit src srcs sourceRoot unpackPhase cargoUpdateHook;
+      name = cargoDepsName;
+      hash = cargoHash;
+      patches = cargoPatches;
+      sha256 = cargoSha256;
+    } // depsExtraArgs)
     else null;
 
   # If we have a cargoSha256 fixed-output derivation, validate it at build time
@@ -96,7 +101,7 @@ in
 # See https://os.phil-opp.com/testing/ for more information.
 assert useSysroot -> !(args.doCheck or true);
 
-stdenv.mkDerivation ((removeAttrs args ["depsExtraArgs"]) // lib.optionalAttrs useSysroot {
+stdenv.mkDerivation ((removeAttrs args [ "depsExtraArgs" "cargoLock" ]) // lib.optionalAttrs useSysroot {
   RUSTFLAGS = "--sysroot ${sysroot} " + (args.RUSTFLAGS or "");
 } // {
   inherit buildAndTestSubdir cargoDeps;