From 9b6f77200f8a88c8b5e5da47e90b73f86aab27b9 Mon Sep 17 00:00:00 2001
From: Andrew Marshall <andrew@johnandrewmarshall.com>
Date: Wed, 22 May 2024 13:34:01 -0400
Subject: [PATCH 1/3] environment: Rework test to assert against full $PATH
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It’s deterministic after all, so test against the full thing for greater
flexibility in testing and confidence in lack of unexpected changes to
previously-untested parts of the default $PATH.

Do this in a subshell to avoid polluting the test script’s environment.
---
 tests/environment-path.nix | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/tests/environment-path.nix b/tests/environment-path.nix
index 7d2f46dd9..5ddaf9c96 100644
--- a/tests/environment-path.nix
+++ b/tests/environment-path.nix
@@ -4,10 +4,18 @@ with lib;
 
 {
   test = ''
-    echo checking /run/current-system/sw/bin in environment >&2
-    grep 'export PATH=.*:/run/current-system/sw/bin' ${config.system.build.setEnvironment}
+    echo 'checking PATH' >&2
+    env_path=$(bash -c 'source ${config.system.build.setEnvironment}; echo $PATH')
 
-    echo checking /bin and /sbin in environment >&2
-    grep 'export PATH=.*:/usr/bin:/usr/sbin:/bin:/sbin' ${config.system.build.setEnvironment}
+    test "$env_path" = "${builtins.concatStringsSep ":" [
+      "/homeless-shelter/.nix-profile/bin"
+      "/run/current-system/sw/bin"
+      "/nix/var/nix/profiles/default/bin"
+      "/usr/local/bin"
+      "/usr/bin"
+      "/usr/sbin"
+      "/bin"
+      "/sbin"
+    ]}"
   '';
 }

From bd0ed8599fd4871e79543e09075dac2c2c25ff2a Mon Sep 17 00:00:00 2001
From: Andrew Marshall <andrew@johnandrewmarshall.com>
Date: Wed, 22 May 2024 13:43:33 -0400
Subject: [PATCH 2/3] environment: Test how order of systemPath and profiles
 manifests

---
 tests/environment-path.nix | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/tests/environment-path.nix b/tests/environment-path.nix
index 5ddaf9c96..0bb9a0558 100644
--- a/tests/environment-path.nix
+++ b/tests/environment-path.nix
@@ -3,19 +3,37 @@
 with lib;
 
 {
+  environment.systemPath = mkMerge [
+    (mkBefore [ "beforePath" ])
+    [ "myPath" ]
+    (mkAfter [ "afterPath" ])
+  ];
+
+  environment.profiles = mkMerge [
+    (mkBefore [ "beforeProfile" ])
+    [ "myProfile" ]
+    (mkAfter [ "afterProfile" ])
+  ];
+
   test = ''
     echo 'checking PATH' >&2
     env_path=$(bash -c 'source ${config.system.build.setEnvironment}; echo $PATH')
 
     test "$env_path" = "${builtins.concatStringsSep ":" [
+      "beforePath"
+      "myPath"
+      "beforeProfile/bin"
       "/homeless-shelter/.nix-profile/bin"
+      "myProfile/bin"
       "/run/current-system/sw/bin"
       "/nix/var/nix/profiles/default/bin"
+      "afterProfile/bin"
       "/usr/local/bin"
       "/usr/bin"
       "/usr/sbin"
       "/bin"
       "/sbin"
+      "afterPath"
     ]}"
   '';
 }

From 7f897008d4f3c7dda86e19106169eb947a0ac308 Mon Sep 17 00:00:00 2001
From: Andrew Marshall <andrew@johnandrewmarshall.com>
Date: Wed, 22 May 2024 09:41:12 -0400
Subject: [PATCH 3/3] environment: Adjust systemPath order to allow injecting
 in the middle
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Previously, it was not possible to inject PATH entries between profiles
and the “default system” PATH entries. This confounds adding, e.g.
Homebrew on aarch64’s non-standard prefix as higher priority than the
builtin system paths, but lower than Nix profiles.

This is a backwards-incompatible change for some users, but should only
be so in the case a user used `mkOrder` with a value between 1000 (the
default priority) and 1200. Value of 1200 chosen as the same delta from
the default as just below in `environment.profiles` (which uses 800),
and mkAfter is 1500 so will still go after this.
---
 modules/environment/default.nix | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/modules/environment/default.nix b/modules/environment/default.nix
index 753ee311f..bb996222f 100644
--- a/modules/environment/default.nix
+++ b/modules/environment/default.nix
@@ -151,7 +151,10 @@ in
 
   config = {
 
-    environment.systemPath = [ (makeBinPath cfg.profiles) "/usr/local/bin:/usr/bin:/usr/sbin:/bin:/sbin" ];
+    environment.systemPath = mkMerge [
+      [ (makeBinPath cfg.profiles) ]
+      (mkOrder 1200 [ "/usr/local/bin:/usr/bin:/usr/sbin:/bin:/sbin" ])
+    ];
 
     # Use user, default and system profiles.
     environment.profiles = mkMerge [