rustPlatform.importCargoLock: add support for git dependencies that u…

…se workspace inheritance

Rust 1.64.0 added support for Cargo workspace inheritance, which allows
for workspace members to inherit values such as dependency version
constraints or package metadata information from their workspaces [0].

This works by having workspace members specify a value as a table, with
`workspace` set to true. Thus, supporting this in importCargoLock is as
simple as walking the workspace member's Cargo.toml, replacing inherited
values with their workspace counterpart.

This is also what a forthcoming Cargo release will do [1], but we can get
ahead of it ;)

[0]: https://blog.rust-lang.org/2022/09/22/Rust-1.64.0.html#cargo-improvements-workspace-inheritance-and-multi-target-builds
[1]: rust-lang/cargo#11414

pkgs/build-support/rust/import-cargo-lock.nix

@@ -1,4 +1,4 @@
-{ fetchgit, fetchurl, lib, runCommand, cargo, jq }:
+{ fetchgit, fetchurl, lib, writers, python3Packages, runCommand, cargo, jq }:
 
 {
   # Cargo lock file
@@ -92,6 +92,11 @@ let
       sha256 = pkg.checksum;
     };
 
+  # Replaces values inherited by workspace members.
+  replaceWorkspaceValues = writers.writePython3 "replace-workspace-values"
+    { libraries = [ python3Packages.toml ]; flakeIgnore = [ "E501" ]; }
+    (builtins.readFile ./replace-workspace-values.py);
+
   # Fetch and unpack a crate.
   mkCrate = pkg:
     let
@@ -170,6 +175,11 @@ let
         cp -prvd "$tree/" $out
         chmod u+w $out
 
+        if grep -q workspace "$out/Cargo.toml"; then
+          chmod u+w "$out/Cargo.toml"
+          ${replaceWorkspaceValues} "$out/Cargo.toml" "${tree}/Cargo.toml"
+        fi
+
         # Cargo is happy with empty metadata.
         printf '{"files":{},"package":null}' > "$out/.cargo-checksum.json"
 

pkgs/build-support/rust/replace-workspace-values.py

@@ -0,0 +1,43 @@
+import sys
+import toml
+
+crate_manifest = toml.load(sys.argv[1])
+workspace_manifest = toml.load(sys.argv[2])
+
+
+def replace_key(table, section, key):
+    if "workspace" in table[key] and table[key]["workspace"] is True:
+        print("replacing " + key)
+
+        replaced = table[key]
+        del replaced["workspace"]
+
+        workspace_copy = workspace_manifest["workspace"][section][key]
+
+        if section == "dependencies":
+            if isinstance(workspace_copy, str):
+                replaced["version"] = workspace_copy
+            else:
+                replaced.update(workspace_copy)
+        elif section == "package":
+            table[key] = replaced = workspace_copy
+
+
+def replace_dependencies(root):
+    for key in ["dependencies", "dev-dependencies", "build-dependencies"]:
+        if key in root:
+            for k, v in root[key].items():
+                replace_key(root[key], "dependencies", k)
+
+
+for key in crate_manifest["package"].keys():
+    replace_key(crate_manifest["package"], "package", key)
+
+replace_dependencies(crate_manifest)
+
+if "target" in crate_manifest:
+    for key in crate_manifest["target"].keys():
+        replace_dependencies(crate_manifest["target"][key])
+
+with open(sys.argv[1], "w") as f:
+    toml.dump(crate_manifest, f)

pkgs/build-support/rust/test/import-cargo-lock/default.nix

@@ -1,4 +1,4 @@
-{ callPackage }:
+{ callPackage, writers, python3Packages }:
 
 # Build like this from nixpkgs root:
 # $ nix-build -A tests.importCargoLock
@@ -11,4 +11,9 @@
   gitDependencyTag = callPackage ./git-dependency-tag { };
   gitDependencyBranch = callPackage ./git-dependency-branch { };
   maturin = callPackage ./maturin { };
+  gitDependencyWorkspaceInheritance = callPackage ./git-dependency-workspace-inheritance {
+    replaceWorkspaceValues = writers.writePython3 "replace-workspace-values"
+      { libraries = [ python3Packages.toml ]; flakeIgnore = [ "E501" ]; }
+      (builtins.readFile ../../replace-workspace-values.py);
+  };
 }

pkgs/build-support/rust/test/import-cargo-lock/git-dependency-workspace-inheritance/crate.toml

@@ -0,0 +1,6 @@
+[package]
+version = { workspace = true }
+
+[dependencies]
+foo = { workspace = true }
+bar = "1.0.0"

pkgs/build-support/rust/test/import-cargo-lock/git-dependency-workspace-inheritance/default.nix

@@ -0,0 +1,7 @@
+{ replaceWorkspaceValues, runCommand }:
+
+runCommand "git-dependency-workspace-inheritance-test" { } ''
+  cp --no-preserve=mode ${./crate.toml} "$out"
+  ${replaceWorkspaceValues} "$out" ${./workspace.toml}
+  diff "$out" ${./want.toml}
+''

pkgs/build-support/rust/test/import-cargo-lock/git-dependency-workspace-inheritance/want.toml

@@ -0,0 +1,8 @@
+[package]
+version = "1.0.0"
+
+[dependencies]
+bar = "1.0.0"
+
+[dependencies.foo]
+version = "1.0.0"

pkgs/build-support/rust/test/import-cargo-lock/git-dependency-workspace-inheritance/workspace.toml

@@ -0,0 +1,5 @@
+[workspace.package]
+version = "1.0.0"
+
+[workspace.dependencies]
+foo = "1.0.0"