tests.nixpkgs-check-by-name: Improve lib path handling in tests

nix-build failed because the tests assume to run in a CWD equal to the
project root, which is not the case in the derivation build.

This commit fixes it by not using hacky `..` references to paths,
and instead uses NIX_PATH for all implicit Nix testing path
dependencies.

Also the root of the `lib` path gets passed in from the `default.nix`
file, so all the relative path handling is done by Nix during evaluation
already, and in the Nix store when possible.

pkgs/test/nixpkgs-check-by-name/default.nix

@@ -9,6 +9,7 @@
 }:
 let
   runtimeExprPath = ./src/eval.nix;
+  nixpkgsLibPath = ../../../lib;
   package =
     rustPlatform.buildRustPackage {
       name = "nixpkgs-check-by-name";
@@ -30,6 +31,8 @@ let
         export NIX_STATE_DIR=$TEST_ROOT/var/nix
         export NIX_STORE_DIR=$TEST_ROOT/store
 
+        export NIXPKGS_LIB_PATH=${nixpkgsLibPath}
+
         # Ensure that even if tests run in parallel, we don't get an error
         # We'd run into https://github.com/NixOS/nix/issues/2706 unless the store is initialised first
         nix-store --init
@@ -44,6 +47,7 @@ let
       '';
       passthru.shell = mkShell {
         env.NIX_CHECK_BY_NAME_EXPR_PATH = toString runtimeExprPath;
+        env.NIXPKGS_LIB_PATH = toString nixpkgsLibPath;
         inputsFrom = [ package ];
       };
     };

pkgs/test/nixpkgs-check-by-name/src/eval.rs

@@ -2,6 +2,8 @@ use crate::nixpkgs_problem::NixpkgsProblem;
 use crate::ratchet;
 use crate::structure;
 use crate::validation::{self, Validation::Success};
+use std::collections::HashMap;
+use std::ffi::OsString;
 use std::path::Path;
 
 use anyhow::Context;
@@ -71,7 +73,7 @@ enum CallPackageVariant {
 pub fn check_values(
     nixpkgs_path: &Path,
     package_names: Vec<String>,
-    eval_accessible_paths: &[&Path],
+    eval_nix_path: &HashMap<String, PathBuf>,
 ) -> validation::Result<ratchet::Nixpkgs> {
     // Write the list of packages we need to check into a temporary JSON file.
     // This can then get read by the Nix evaluation.
@@ -120,9 +122,13 @@ pub fn check_values(
         .arg(nixpkgs_path);
 
     // Also add extra paths that need to be accessible
-    for path in eval_accessible_paths {
+    for (name, path) in eval_nix_path {
         command.arg("-I");
-        command.arg(path);
+        let mut name_value = OsString::new();
+        name_value.push(name);
+        name_value.push("=");
+        name_value.push(path);
+        command.arg(name_value);
     }
     command.args(["-I", &expr_path]);
     command.arg(expr_path);

pkgs/test/nixpkgs-check-by-name/src/main.rs

@@ -12,6 +12,7 @@ use crate::validation::Validation::Success;
 use anyhow::Context;
 use clap::Parser;
 use colored::Colorize;
+use std::collections::HashMap;
 use std::io;
 use std::path::{Path, PathBuf};
 use std::process::ExitCode;
@@ -44,7 +45,12 @@ pub struct Args {
 
 fn main() -> ExitCode {
     let args = Args::parse();
-    match process(&args.base, &args.nixpkgs, &[], &mut io::stderr()) {
+    match process(
+        &args.base,
+        &args.nixpkgs,
+        &HashMap::new(),
+        &mut io::stderr(),
+    ) {
         Ok(true) => {
             eprintln!("{}", "Validated successfully".green());
             ExitCode::SUCCESS
@@ -77,15 +83,15 @@ fn main() -> ExitCode {
 pub fn process<W: io::Write>(
     base_nixpkgs: &Path,
     main_nixpkgs: &Path,
-    eval_accessible_paths: &[&Path],
+    eval_nix_path: &HashMap<String, PathBuf>,
     error_writer: &mut W,
 ) -> anyhow::Result<bool> {
     // Check the main Nixpkgs first
-    let main_result = check_nixpkgs(main_nixpkgs, eval_accessible_paths, error_writer)?;
+    let main_result = check_nixpkgs(main_nixpkgs, eval_nix_path, error_writer)?;
     let check_result = main_result.result_map(|nixpkgs_version| {
         // If the main Nixpkgs doesn't have any problems, run the ratchet checks against the base
         // Nixpkgs
-        check_nixpkgs(base_nixpkgs, eval_accessible_paths, error_writer)?.result_map(
+        check_nixpkgs(base_nixpkgs, eval_nix_path, error_writer)?.result_map(
             |base_nixpkgs_version| {
                 Ok(ratchet::Nixpkgs::compare(
                     base_nixpkgs_version,
@@ -113,7 +119,7 @@ pub fn process<W: io::Write>(
 /// ratchet check against another result.
 pub fn check_nixpkgs<W: io::Write>(
     nixpkgs_path: &Path,
-    eval_accessible_paths: &[&Path],
+    eval_nix_path: &HashMap<String, PathBuf>,
     error_writer: &mut W,
 ) -> validation::Result<ratchet::Nixpkgs> {
     Ok({
@@ -134,7 +140,7 @@ pub fn check_nixpkgs<W: io::Write>(
         } else {
             check_structure(&nixpkgs_path)?.result_map(|package_names|
                 // Only if we could successfully parse the structure, we do the evaluation checks
-                eval::check_values(&nixpkgs_path, package_names, eval_accessible_paths))?
+                eval::check_values(&nixpkgs_path, package_names, eval_nix_path))?
         }
     })
 }
@@ -144,8 +150,10 @@ mod tests {
     use crate::process;
     use crate::utils;
     use anyhow::Context;
+    use std::collections::HashMap;
     use std::fs;
     use std::path::Path;
+    use std::path::PathBuf;
     use tempfile::{tempdir_in, TempDir};
 
     #[test]
@@ -226,9 +234,19 @@ mod tests {
     }
 
     fn test_nixpkgs(name: &str, path: &Path, expected_errors: &str) -> anyhow::Result<()> {
-        let mock_nixpkgs_path = Path::new("tests/mock-nixpkgs.nix");
-        let real_lib_path = Path::new("../../../lib");
-        let extra_nix_path = [mock_nixpkgs_path, real_lib_path];
+        let eval_nix_path = HashMap::from([
+            (
+                "test-nixpkgs".to_string(),
+                PathBuf::from("tests/mock-nixpkgs.nix"),
+            ),
+            (
+                "test-nixpkgs/lib".to_string(),
+                PathBuf::from(
+                    std::env::var("NIXPKGS_LIB_PATH")
+                        .with_context(|| "Could not get environment variable NIXPKGS_LIB_PATH")?,
+                ),
+            ),
+        ]);
 
         let base_path = path.join("base");
         let base_nixpkgs = if base_path.exists() {
@@ -240,7 +258,7 @@ mod tests {
         // We don't want coloring to mess up the tests
         let writer = temp_env::with_var("NO_COLOR", Some("1"), || -> anyhow::Result<_> {
             let mut writer = vec![];
-            process(base_nixpkgs, &path, &extra_nix_path, &mut writer)
+            process(base_nixpkgs, &path, &eval_nix_path, &mut writer)
                 .with_context(|| format!("Failed test case {name}"))?;
             Ok(writer)
         })?;

pkgs/test/nixpkgs-check-by-name/tests/broken-autocall/default.nix

@@ -1,4 +1,4 @@
 args:
 builtins.removeAttrs
-  (import ../mock-nixpkgs.nix { root = ./.; } args)
+  (import <test-nixpkgs> { root = ./.; } args)
   [ "foo" ]

pkgs/test/nixpkgs-check-by-name/tests/empty-base/default.nix

@@ -1 +1 @@
-import ../mock-nixpkgs.nix { root = ./.; }
+import <test-nixpkgs> { root = ./.; }

pkgs/test/nixpkgs-check-by-name/tests/incorrect-shard/default.nix

@@ -1 +1 @@
-import ../mock-nixpkgs.nix { root = ./.; }
+import <test-nixpkgs> { root = ./.; }

pkgs/test/nixpkgs-check-by-name/tests/internalCallPackage/default.nix

@@ -1 +1 @@
-import ../mock-nixpkgs.nix { root = ./.; }
+import <test-nixpkgs> { root = ./.; }

pkgs/test/nixpkgs-check-by-name/tests/invalid-package-name/default.nix

@@ -1 +1 @@
-import ../mock-nixpkgs.nix { root = ./.; }
+import <test-nixpkgs> { root = ./.; }

pkgs/test/nixpkgs-check-by-name/tests/invalid-shard-name/default.nix

@@ -1 +1 @@
-import ../mock-nixpkgs.nix { root = ./.; }
+import <test-nixpkgs> { root = ./.; }

pkgs/test/nixpkgs-check-by-name/tests/missing-package-nix/default.nix

@@ -1 +1 @@
-import ../mock-nixpkgs.nix { root = ./.; }
+import <test-nixpkgs> { root = ./.; }

pkgs/test/nixpkgs-check-by-name/tests/mock-nixpkgs.nix

@@ -25,7 +25,7 @@ It returns a Nixpkgs-like function that can be auto-called and evaluates to an a
 let
 
   # Simplified versions of lib functions
-  lib = import ../../../../lib;
+  lib = import <test-nixpkgs/lib>;
 
   # The base fixed-point function to populate the resulting attribute set
   pkgsFun = self: {

pkgs/test/nixpkgs-check-by-name/tests/move-to-non-by-name/base/default.nix

@@ -1 +1 @@
-import ../../mock-nixpkgs.nix { root = ./.; }
+import <test-nixpkgs> { root = ./.; }

pkgs/test/nixpkgs-check-by-name/tests/move-to-non-by-name/default.nix

@@ -1 +1 @@
-import ../mock-nixpkgs.nix { root = ./.; }
+import <test-nixpkgs> { root = ./.; }

pkgs/test/nixpkgs-check-by-name/tests/new-package-non-by-name/base/default.nix

@@ -1 +1 @@
-import ../../mock-nixpkgs.nix { root = ./.; }
+import <test-nixpkgs> { root = ./.; }

pkgs/test/nixpkgs-check-by-name/tests/new-package-non-by-name/default.nix

@@ -1 +1 @@
-import ../mock-nixpkgs.nix { root = ./.; }
+import <test-nixpkgs> { root = ./.; }

pkgs/test/nixpkgs-check-by-name/tests/no-by-name/default.nix

@@ -1 +1 @@
-import ../mock-nixpkgs.nix { root = ./.; }
+import <test-nixpkgs> { root = ./.; }

pkgs/test/nixpkgs-check-by-name/tests/no-eval/default.nix

@@ -1 +1 @@
-import ../mock-nixpkgs.nix { root = ./.; }
+import <test-nixpkgs> { root = ./.; }

pkgs/test/nixpkgs-check-by-name/tests/non-attrs/default.nix

@@ -1 +1 @@
-import ../mock-nixpkgs.nix { root = ./.; }
+import <test-nixpkgs> { root = ./.; }

pkgs/test/nixpkgs-check-by-name/tests/non-derivation/default.nix

@@ -1 +1 @@
-import ../mock-nixpkgs.nix { root = ./.; }
+import <test-nixpkgs> { root = ./.; }

pkgs/test/nixpkgs-check-by-name/tests/one-letter/default.nix

@@ -1 +1 @@
-import ../mock-nixpkgs.nix { root = ./.; }
+import <test-nixpkgs> { root = ./.; }

pkgs/test/nixpkgs-check-by-name/tests/only-callPackage-derivations/default.nix

@@ -1 +1 @@
-import ../mock-nixpkgs.nix { root = ./.; }
+import <test-nixpkgs> { root = ./.; }

pkgs/test/nixpkgs-check-by-name/tests/override-different-file/default.nix

@@ -1 +1 @@
-import ../mock-nixpkgs.nix { root = ./.; }
+import <test-nixpkgs> { root = ./.; }

pkgs/test/nixpkgs-check-by-name/tests/override-empty-arg-gradual/base/default.nix

@@ -1 +1 @@
-import ../../mock-nixpkgs.nix { root = ./.; }
+import <test-nixpkgs> { root = ./.; }

pkgs/test/nixpkgs-check-by-name/tests/override-empty-arg-gradual/default.nix

@@ -1 +1 @@
-import ../mock-nixpkgs.nix { root = ./.; }
+import <test-nixpkgs> { root = ./.; }

pkgs/test/nixpkgs-check-by-name/tests/override-empty-arg/base/default.nix

@@ -1 +1 @@
-import ../../mock-nixpkgs.nix { root = ./.; }
+import <test-nixpkgs> { root = ./.; }

pkgs/test/nixpkgs-check-by-name/tests/override-empty-arg/default.nix

@@ -1 +1 @@
-import ../mock-nixpkgs.nix { root = ./.; }
+import <test-nixpkgs> { root = ./.; }

pkgs/test/nixpkgs-check-by-name/tests/override-no-call-package/default.nix

@@ -1 +1 @@
-import ../mock-nixpkgs.nix { root = ./.; }
+import <test-nixpkgs> { root = ./.; }

pkgs/test/nixpkgs-check-by-name/tests/override-no-file/default.nix

@@ -1 +1 @@
-import ../mock-nixpkgs.nix { root = ./.; }
+import <test-nixpkgs> { root = ./.; }

pkgs/test/nixpkgs-check-by-name/tests/override-success/default.nix

@@ -1 +1 @@
-import ../mock-nixpkgs.nix { root = ./.; }
+import <test-nixpkgs> { root = ./.; }

pkgs/test/nixpkgs-check-by-name/tests/package-dir-is-file/default.nix

@@ -1 +1 @@
-import ../mock-nixpkgs.nix { root = ./.; }
+import <test-nixpkgs> { root = ./.; }

pkgs/test/nixpkgs-check-by-name/tests/package-nix-dir/default.nix

@@ -1 +1 @@
-import ../mock-nixpkgs.nix { root = ./.; }
+import <test-nixpkgs> { root = ./.; }

pkgs/test/nixpkgs-check-by-name/tests/ref-absolute/default.nix

@@ -1 +1 @@
-import ../mock-nixpkgs.nix { root = ./.; }
+import <test-nixpkgs> { root = ./.; }

pkgs/test/nixpkgs-check-by-name/tests/ref-escape/default.nix

@@ -1 +1 @@
-import ../mock-nixpkgs.nix { root = ./.; }
+import <test-nixpkgs> { root = ./.; }

pkgs/test/nixpkgs-check-by-name/tests/ref-nix-path/default.nix

@@ -1 +1 @@
-import ../mock-nixpkgs.nix { root = ./.; }
+import <test-nixpkgs> { root = ./.; }

pkgs/test/nixpkgs-check-by-name/tests/ref-parse-failure/default.nix

@@ -1 +1 @@
-import ../mock-nixpkgs.nix { root = ./.; }
+import <test-nixpkgs> { root = ./.; }

pkgs/test/nixpkgs-check-by-name/tests/ref-path-subexpr/default.nix

@@ -1 +1 @@
-import ../mock-nixpkgs.nix { root = ./.; }
+import <test-nixpkgs> { root = ./.; }

pkgs/test/nixpkgs-check-by-name/tests/ref-success/default.nix

@@ -1 +1 @@
-import ../mock-nixpkgs.nix { root = ./.; }
+import <test-nixpkgs> { root = ./.; }

pkgs/test/nixpkgs-check-by-name/tests/shard-file/default.nix

@@ -1 +1 @@
-import ../mock-nixpkgs.nix { root = ./.; }
+import <test-nixpkgs> { root = ./.; }

pkgs/test/nixpkgs-check-by-name/tests/sorted-order/default.nix

@@ -1 +1 @@
-import ../mock-nixpkgs.nix { root = ./.; }
+import <test-nixpkgs> { root = ./.; }

pkgs/test/nixpkgs-check-by-name/tests/success/default.nix

@@ -1 +1 @@
-import ../mock-nixpkgs.nix { root = ./.; }
+import <test-nixpkgs> { root = ./.; }

pkgs/test/nixpkgs-check-by-name/tests/symlink-escape/default.nix

@@ -1 +1 @@
-import ../mock-nixpkgs.nix { root = ./.; }
+import <test-nixpkgs> { root = ./.; }

pkgs/test/nixpkgs-check-by-name/tests/symlink-invalid/default.nix

@@ -1 +1 @@
-import ../mock-nixpkgs.nix { root = ./.; }
+import <test-nixpkgs> { root = ./.; }

pkgs/test/nixpkgs-check-by-name/tests/uppercase/default.nix

@@ -1 +1 @@
-import ../mock-nixpkgs.nix { root = ./.; }
+import <test-nixpkgs> { root = ./.; }

pkgs/test/nixpkgs-check-by-name/tests/with-readme/default.nix

@@ -1 +1 @@
-import ../mock-nixpkgs.nix { root = ./.; }
+import <test-nixpkgs> { root = ./.; }