Automatically build most packages without passing format param

We should never have to use `format = "setuptools"` since pip can
_also_ handle setuptools packages.

This uses a custom pipBuildHook that removes pyproject.toml in case
there is also a setup.py in the same sources.

default.nix

@@ -102,7 +102,7 @@ let
                     # The canonical name is setuptools-scm
                     setuptools-scm = super.setuptools_scm;
 
-                    inherit (hooks) removePathDependenciesHook poetry2nixFixupHook;
+                    inherit (hooks) pipBuildHook removePathDependenciesHook poetry2nixFixupHook;
                   }
             )
             # Null out any filtered packages, we don't want python.pkgs from nixpkgs

hooks/default.nix

@@ -2,9 +2,12 @@
 , callPackage
 , makeSetupHook
 , yj
+, wheel
+, pip
 }:
 let
   pythonInterpreter = python.pythonForBuild.interpreter;
+  pythonSitePackages = python.sitePackages;
 in
 {
 
@@ -21,6 +24,17 @@ in
       } ./remove-path-dependencies.sh
   ) {};
 
+  pipBuildHook = callPackage (
+    { pip, wheel }:
+      makeSetupHook {
+        name = "pip-build-hook.sh";
+        deps = [ pip wheel ];
+        substitutions = {
+          inherit pythonInterpreter pythonSitePackages;
+        };
+      } ./pip-build-hook.sh
+  ) {};
+
   poetry2nixFixupHook = callPackage (
     {}:
       makeSetupHook {

hooks/pip-build-hook.sh

@@ -0,0 +1,50 @@
+# Setup hook to use for pip projects
+echo "Sourcing pip-build-hook"
+
+pipBuildPhase() {
+    echo "Executing pipBuildPhase"
+    runHook preBuild
+
+    # Prefer using setup.py to avoid build-system dependencies if we have a setup.py
+    if [ -z "${dontPreferSetupPy-}" ]; then
+      if test -e setup.py && test -e pyproject.toml; then
+        echo "Removing pyproject.toml..."
+        rm -f pyproject.toml
+      fi
+    fi
+
+    mkdir -p dist
+    echo "Creating a wheel..."
+    @pythonInterpreter@ -m pip wheel --no-index --no-deps --no-clean --no-build-isolation --wheel-dir dist .
+    echo "Finished creating a wheel..."
+
+    runHook postBuild
+    echo "Finished executing pipBuildPhase"
+}
+
+pipShellHook() {
+    echo "Executing pipShellHook"
+    runHook preShellHook
+
+    # Long-term setup.py should be dropped.
+    if [ -e pyproject.toml ]; then
+      tmp_path=$(mktemp -d)
+      export PATH="$tmp_path/bin:$PATH"
+      export PYTHONPATH="$tmp_path/@pythonSitePackages@:$PYTHONPATH"
+      mkdir -p "$tmp_path/@pythonSitePackages@"
+      @pythonInterpreter@ -m pip install -e . --prefix "$tmp_path" >&2
+    fi
+
+    runHook postShellHook
+    echo "Finished executing pipShellHook"
+}
+
+if [ -z "${dontUsePipBuild-}" ] && [ -z "${buildPhase-}" ]; then
+    echo "Using pipBuildPhase"
+    buildPhase=pipBuildPhase
+fi
+
+if [ -z "${shellHook-}" ]; then
+    echo "Using pipShellHook"
+    shellHook=pipShellHook
+fi

hooks/pyproject-without-path.py

@@ -6,7 +6,14 @@ import sys
 
 data = json.load(sys.stdin)
 
-for dep in data['tool']['poetry']['dependencies'].values():
+
+def get_deep(o, path):
+    for p in path.split('.'):
+        o = o.get(p, {})
+    return o
+
+
+for dep in get_deep(data, 'tool.poetry.dependencies').values():
     if isinstance(dep, dict):
         try:
             del dep['path'];

mk-poetry-dep.nix

@@ -74,10 +74,10 @@ pythonPackages.callPackage (
           format =
             if _isEgg then "egg"
             else if lib.strings.hasSuffix ".whl" name then "wheel"
-            else "setuptools";
+            else "pyproject";
           kind =
             if _isEgg then python.pythonVersion
-            else if format == "setuptools" then "source"
+            else if format == "pyproject" then "source"
             else (builtins.elemAt (lib.strings.splitString "-" name) 2);
         };
 
@@ -89,7 +89,7 @@ pythonPackages.callPackage (
       ];
       baseBuildInputs = lib.optional (! lib.elem name skipSetupToolsSCM) pythonPackages.setuptools-scm;
 
-      format = if isLocal then "pyproject" else if isGit then "setuptools" else fileInfo.format;
+      format = if isLocal then "pyproject" else if isGit then "pyproject" else fileInfo.format;
     in
 
       buildPythonPackage {