From 6a28566db663fe8b185142e0d9cfdb988f6b04a9 Mon Sep 17 00:00:00 2001
From: Robert Hensing <robert@roberthensing.nl>
Date: Tue, 25 Jun 2024 15:49:39 +0200
Subject: [PATCH] refact: concatMapAttrs -> flatMapAttrs

This should be slightly easier to read.
We could apply this to all concatMapAttrs calls.
---
 flake.nix | 31 +++++++++++++++++++++++--------
 1 file changed, 23 insertions(+), 8 deletions(-)

diff --git a/flake.nix b/flake.nix
index aac45af34..1be9d2fc0 100644
--- a/flake.nix
+++ b/flake.nix
@@ -58,6 +58,18 @@
         "stdenv"
       ];
 
+      /**
+        `flatMapAttrs attrs f` applies `f` to each attribute in `attrs` and
+        merges the results into a single attribute set.
+
+        This can be nested to form a build matrix where all the attributes
+        generated by the innermost `f` are returned as is.
+        (Provided that the names are unique.)
+
+        See https://nixos.org/manual/nixpkgs/stable/index.html#function-library-lib.attrsets.concatMapAttrs
+       */
+      flatMapAttrs = attrs: f: lib.concatMapAttrs f attrs;
+
       forAllSystems = lib.genAttrs systems;
 
       forAllCrossSystems = lib.genAttrs crossSystems;
@@ -319,17 +331,20 @@
         # system, we should reenable this.
         #perlBindings = self.hydraJobs.perlBindings.${system};
       }
-      // lib.concatMapAttrs (nixpkgsPrefix: nixpkgs: 
-          lib.concatMapAttrs (pkgName: pkg:
-            lib.concatMapAttrs (testName: test: {
-              # Add "passthru" tests
-              "${nixpkgsPrefix}${pkgName}-${testName}" = test;
-            }) pkg.tests or {}
-          ) nixpkgs.nix-components
-        ) {
+      # Add "passthru" tests
+      // flatMapAttrs {
           "" = nixpkgsFor.${system}.native;
           "static-" = nixpkgsFor.${system}.static;
         }
+        (nixpkgsPrefix: nixpkgs: 
+          flatMapAttrs nixpkgs.nix-components
+            (pkgName: pkg:
+              flatMapAttrs pkg.tests or {}
+              (testName: test: {
+                "${nixpkgsPrefix}${pkgName}-${testName}" = test;
+              })
+            )
+        )
       // devFlake.checks.${system} or {}
       );