From 3f976d822b7b37fc6fb8e6f157c2dd05e7e94e89 Mon Sep 17 00:00:00 2001
From: Patryk Wychowaniec <pwychowaniec@pm.me>
Date: Wed, 6 Sep 2023 14:05:28 +0200
Subject: [PATCH] Support unused dependencies

Cargo stashes unused patches into a special section of the Cargo.lock
file:

```
[[patch.unused]]
name = "uuid"
version = "1.4.1"
source = "git+https://github.com/uuid-rs/uuid#50f70278de02c106650b8d6deb325dd59b5f2a24"
```

... a section that we, currently, don't read.

Ignoring that section causes the build to fail because even if the patch
is unused, when the source is unavailable, Cargo tries to fetch it
(which, understandably, is not possible inside the sandbox).

This commit extends our logic so that we download both the "used" and
"unused" dependencies.

Closes https://github.com/nix-community/naersk/issues/308.
---
 lib.nix                                     |  9 ++++++++-
 test/fast/default.nix                       |  1 +
 test/fast/unused-patch/default.nix          | 15 +++++++++++++++
 test/fast/unused-patch/fixtures/Cargo.lock  | 12 ++++++++++++
 test/fast/unused-patch/fixtures/Cargo.toml  |  7 +++++++
 test/fast/unused-patch/fixtures/src/main.rs |  3 +++
 6 files changed, 46 insertions(+), 1 deletion(-)
 create mode 100644 test/fast/unused-patch/default.nix
 create mode 100644 test/fast/unused-patch/fixtures/Cargo.lock
 create mode 100644 test/fast/unused-patch/fixtures/Cargo.toml
 create mode 100644 test/fast/unused-patch/fixtures/src/main.rs

diff --git a/lib.nix b/lib.nix
index 33a5875..1e71da3 100644
--- a/lib.nix
+++ b/lib.nix
@@ -99,7 +99,14 @@ rec
       } // (lib.optionalAttrs (! isNull branch) { inherit branch; })
         // (lib.optionalAttrs (! isNull tag) { inherit tag; })
         // (lib.optionalAttrs (! isNull rev) { inherit rev; });
-      packageLocks = builtins.map parseLock (lib.filter query cargolock.package);
+
+      usedPackageLocks =
+        builtins.map parseLock (lib.filter query cargolock.package);
+
+      unusedPackageLocks =
+        builtins.map parseLock (lib.filter query ((cargolock.patch or []).unused or []));
+
+      packageLocks = usedPackageLocks ++ unusedPackageLocks;
 
       mkFetch = lock: {
         key = lock.rev or lock.tag or lock.branch or lock.revision
diff --git a/test/fast/default.nix b/test/fast/default.nix
index ee063b2..3eb1091 100644
--- a/test/fast/default.nix
+++ b/test/fast/default.nix
@@ -16,6 +16,7 @@ args: {
   simple-dep = import ./simple-dep args;
   simple-dep-patched = import ./simple-dep-patched args;
   symlinks = import ./symlinks args;
+  unused-patch = import ./unused-patch args;
   workspace = import ./workspace args;
   workspace-build-rs = import ./workspace-build-rs args;
   workspace-patched = import ./workspace-patched args;
diff --git a/test/fast/unused-patch/default.nix b/test/fast/unused-patch/default.nix
new file mode 100644
index 0000000..2f6ea43
--- /dev/null
+++ b/test/fast/unused-patch/default.nix
@@ -0,0 +1,15 @@
+{ naersk, pkgs, ... }:
+let
+  app = naersk.buildPackage {
+    src = ./fixtures;
+  };
+
+in
+if builtins.compareVersions pkgs.lib.version "22.11" <= 0 then
+  # Executing this test requires nixpkgs > 22.11 due to changes to the TOML
+  # serialization function.
+  #
+  # See `writeTOML` in this repository for more details.
+  true
+else
+  app
diff --git a/test/fast/unused-patch/fixtures/Cargo.lock b/test/fast/unused-patch/fixtures/Cargo.lock
new file mode 100644
index 0000000..13d034c
--- /dev/null
+++ b/test/fast/unused-patch/fixtures/Cargo.lock
@@ -0,0 +1,12 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "app"
+version = "0.1.0"
+
+[[patch.unused]]
+name = "uuid"
+version = "1.4.1"
+source = "git+https://github.com/uuid-rs/uuid#50f70278de02c106650b8d6deb325dd59b5f2a24"
diff --git a/test/fast/unused-patch/fixtures/Cargo.toml b/test/fast/unused-patch/fixtures/Cargo.toml
new file mode 100644
index 0000000..3487e36
--- /dev/null
+++ b/test/fast/unused-patch/fixtures/Cargo.toml
@@ -0,0 +1,7 @@
+[package]
+name = "app"
+version = "0.1.0"
+edition = "2018"
+
+[patch.crates-io]
+uuid = { git = "https://github.com/uuid-rs/uuid" }
diff --git a/test/fast/unused-patch/fixtures/src/main.rs b/test/fast/unused-patch/fixtures/src/main.rs
new file mode 100644
index 0000000..e7a11a9
--- /dev/null
+++ b/test/fast/unused-patch/fixtures/src/main.rs
@@ -0,0 +1,3 @@
+fn main() {
+    println!("Hello, world!");
+}