From d9a33d69a9c421d64c8d925428864e93be895dcc Mon Sep 17 00:00:00 2001
From: Patryk Wychowaniec <pwychowaniec@pm.me>
Date: Wed, 5 Jul 2023 09:50:33 +0200
Subject: [PATCH] Use checksums for recreating crates.io's directory

Closes https://github.com/nix-community/naersk/issues/138.
---
 build.nix                                     | 32 ++++++++++++++++++-
 test/fast/default.nix                         |  1 +
 .../duplicated-cargo-lock-items/default.nix   |  6 ++++
 .../fixtures/Cargo.lock                       | 22 +++++++++++++
 .../fixtures/Cargo.toml                       |  8 +++++
 .../fixtures/src/main.rs                      |  3 ++
 6 files changed, 71 insertions(+), 1 deletion(-)
 create mode 100644 test/fast/duplicated-cargo-lock-items/default.nix
 create mode 100644 test/fast/duplicated-cargo-lock-items/fixtures/Cargo.lock
 create mode 100644 test/fast/duplicated-cargo-lock-items/fixtures/Cargo.toml
 create mode 100644 test/fast/duplicated-cargo-lock-items/fixtures/src/main.rs

diff --git a/build.nix b/build.nix
index 2c814c1..8ab8d97 100644
--- a/build.nix
+++ b/build.nix
@@ -404,7 +404,37 @@ let
     ''
       mkdir -p $out
       tar -xzf ${crate} -C $out
-      echo '{"package":"${sha256}","files":{}}' > $out/${name}-${version}/.cargo-checksum.json
+
+      # Most filesystems have a maximum filename length of 255
+      dest="$out/$(echo "${name}-${version}-${sha256}" | head -c 255)"
+
+      # Unpacked crates contain a directory named after package's name and its
+      # version - here we're renaming that directory to contain the package's
+      # checksum as well, to avoid clashes in edge cases like:
+      #
+      # ```
+      # [dependencies]
+      # rand_core = "0.6.1"
+      # rand = { git = "https://github.com/rust-random/rand.git", rev = "...", package = "rand_core" }
+      # ```
+      #
+      # ... which might end up having similar entries in the Cargo.lock file:
+      #
+      # ```
+      # [[package]]
+      # name = "rand_core"
+      # version = "0.6.1"
+      # source = "registry+https://github.com/rust-lang/crates.io-index"
+      # checksum = "..."
+      #
+      # [[package]]
+      # name = "rand_core"
+      # version = "0.6.1"
+      # source = "git+https://github.com/rust-random/rand.git?rev=..."
+      # ```
+      mv "$out/${name}-${version}" "$dest"
+
+      echo '{"package":"${sha256}","files":{}}' > "$dest/.cargo-checksum.json"
     '';
 
   unpackGitDependency = { checkout, key, name, url, ... }:
diff --git a/test/fast/default.nix b/test/fast/default.nix
index e455152..18582e4 100644
--- a/test/fast/default.nix
+++ b/test/fast/default.nix
@@ -2,6 +2,7 @@ args: {
   cargo-wildcard = import ./cargo-wildcard args;
   default-run = import ./default-run args;
   dummyfication = import ./dummyfication args;
+  duplicated-cargo-lock-items = import ./duplicated-cargo-lock-items args;
   git-dep = import ./git-dep args;
   git-dep-by-branch = import ./git-dep-by-branch args;
   git-dep-by-branch-with-slash = import ./git-dep-by-branch-with-slash args;
diff --git a/test/fast/duplicated-cargo-lock-items/default.nix b/test/fast/duplicated-cargo-lock-items/default.nix
new file mode 100644
index 0000000..d34c380
--- /dev/null
+++ b/test/fast/duplicated-cargo-lock-items/default.nix
@@ -0,0 +1,6 @@
+{ naersk, ... }:
+
+naersk.buildPackage {
+  src = ./fixtures;
+  doCheck = true;
+}
diff --git a/test/fast/duplicated-cargo-lock-items/fixtures/Cargo.lock b/test/fast/duplicated-cargo-lock-items/fixtures/Cargo.lock
new file mode 100644
index 0000000..74a809d
--- /dev/null
+++ b/test/fast/duplicated-cargo-lock-items/fixtures/Cargo.lock
@@ -0,0 +1,22 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "app"
+version = "0.1.0"
+dependencies = [
+ "rand_core 0.6.1",
+ "rand_core 0.6.4",
+]
+
+[[package]]
+name = "rand_core"
+version = "0.6.1"
+source = "git+https://github.com/rust-random/rand.git?rev=bda997404d9ab8a89d590734d8b0bb72aed10758#bda997404d9ab8a89d590734d8b0bb72aed10758"
+
+[[package]]
+name = "rand_core"
+version = "0.6.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c026d7df8b298d90ccbbc5190bd04d85e159eaf5576caeacf8741da93ccbd2e5"
diff --git a/test/fast/duplicated-cargo-lock-items/fixtures/Cargo.toml b/test/fast/duplicated-cargo-lock-items/fixtures/Cargo.toml
new file mode 100644
index 0000000..17a64c8
--- /dev/null
+++ b/test/fast/duplicated-cargo-lock-items/fixtures/Cargo.toml
@@ -0,0 +1,8 @@
+[package]
+name = "app"
+version = "0.1.0"
+edition = "2018"
+
+[dependencies]
+rand = { git = "https://github.com/rust-random/rand.git", rev = "bda997404d9ab8a89d590734d8b0bb72aed10758", package = "rand_core" }
+rand_core = "0.6.1"
diff --git a/test/fast/duplicated-cargo-lock-items/fixtures/src/main.rs b/test/fast/duplicated-cargo-lock-items/fixtures/src/main.rs
new file mode 100644
index 0000000..e7a11a9
--- /dev/null
+++ b/test/fast/duplicated-cargo-lock-items/fixtures/src/main.rs
@@ -0,0 +1,3 @@
+fn main() {
+    println!("Hello, world!");
+}