From e4a98cf325990113185ae615fb5cf75235b749a7 Mon Sep 17 00:00:00 2001
From: Sem Mulder <sem@mulderke.net>
Date: Mon, 9 May 2022 17:27:24 +0200
Subject: [PATCH] Reset PYTHONPATH before running Python script in hooks

---
 hooks/default.nix                    | 64 +++++++++++++---------------
 hooks/remove-special-dependencies.sh |  7 ++-
 2 files changed, 36 insertions(+), 35 deletions(-)

diff --git a/hooks/default.nix b/hooks/default.nix
index 20f1756..f6d1ea5 100644
--- a/hooks/default.nix
+++ b/hooks/default.nix
@@ -9,44 +9,40 @@ let
   callPackage = python.pythonForBuild.pkgs.callPackage;
   pythonInterpreter = python.pythonForBuild.interpreter;
   pythonSitePackages = python.sitePackages;
+
   nonOverlayedPython = pkgs.python3.pythonForBuild.withPackages (ps: [ ps.tomlkit ]);
+  makeRemoveSpecialDependenciesHook = { fields, kind }:
+    nonOverlayedPython.pkgs.callPackage
+      (
+        {}:
+        makeSetupHook
+          {
+            name = "remove-path-dependencies.sh";
+            deps = [ ];
+            substitutions = {
+              # NOTE: We have to use a non-overlayed Python here because otherwise we run into an infinite recursion
+              # because building of tomlkit and its dependencies also use these hooks.
+              pythonPath = nonOverlayedPython.pkgs.makePythonPath [ nonOverlayedPython ];
+              pythonInterpreter = nonOverlayedPython.interpreter;
+              pyprojectPatchScript = "${./pyproject-without-special-deps.py}";
+              fields = fields;
+              kind = kind;
+            };
+          } ./remove-special-dependencies.sh
+      )
+      { };
 in
 {
-  # NOTE: We have to use a non-overlayed Python here because otherwise we run into an infinite recursion
-  # because building of tomlkit and its dependencies also use these hooks.
-  removePathDependenciesHook = nonOverlayedPython.pkgs.callPackage
-    (
-      {}:
-      makeSetupHook
-        {
-          name = "remove-path-dependencies.sh";
-          deps = [ ];
-          substitutions = {
-            pythonInterpreter = nonOverlayedPython.interpreter;
-            pyprojectPatchScript = "${./pyproject-without-special-deps.py}";
-            fields = [ "path" ];
-            kind = "path";
-          };
-        } ./remove-special-dependencies.sh
-    )
-    { };
+  removePathDependenciesHook = makeRemoveSpecialDependenciesHook {
+    fields = [ "path" ];
+    kind = "path";
+  };
+
+  removeGitDependenciesHook = makeRemoveSpecialDependenciesHook {
+    fields = [ "git" "branch" "rev" "tag" ];
+    kind = "git";
+  };
 
-  removeGitDependenciesHook = nonOverlayedPython.pkgs.callPackage
-    (
-      {}:
-      makeSetupHook
-        {
-          name = "remove-git-dependencies.sh";
-          deps = [ ];
-          substitutions = {
-            pythonInterpreter = nonOverlayedPython.interpreter;
-            pyprojectPatchScript = "${./pyproject-without-special-deps.py}";
-            fields = [ "git" "branch" "rev" "tag" ];
-            kind = "git";
-          };
-        } ./remove-special-dependencies.sh
-    )
-    { };
 
   pipBuildHook = callPackage
     (
diff --git a/hooks/remove-special-dependencies.sh b/hooks/remove-special-dependencies.sh
index a20b204..904efa6 100644
--- a/hooks/remove-special-dependencies.sh
+++ b/hooks/remove-special-dependencies.sh
@@ -1,11 +1,16 @@
 remove-@kind@-dependencies-hook() {
+    # Tell poetry not to resolve special dependencies. Any version is fine!
+
     if ! test -f pyproject.toml; then
         return
     fi
 
     echo "Removing @kind@ dependencies"
 
-    # Tell poetry not to resolve special dependencies. Any version is fine!
+    # NOTE: We have to reset PYTHONPATH to avoid having propagatedBuildInputs
+    # from the currently building derivation leaking into our unrelated Python
+    # environment.
+    PYTHONPATH=@pythonPath@ \
     @pythonInterpreter@ \
     @pyprojectPatchScript@ \
       --fields-to-remove @fields@ < pyproject.toml > pyproject.formatted.toml