From 61f202c0170785addbbc449e4de61cc5886f0833 Mon Sep 17 00:00:00 2001
From: Alexandru Ardelean <ardeleanalex@gmail.com>
Date: Mon, 15 Nov 2021 09:26:29 +0200
Subject: [PATCH] python-build: add support for pyproject.toml files

A new PEP 517 (https://www.python.org/dev/peps/pep-0517/) has defined that
Python packages can be shipped without any `setup.py` file, and that a
`pyproject.toml` file is sufficient.

A `setup.py` shim layer is suggested as a method for running the build.

For these cases, we will add a support in the OpenWrt build-system to
provide the default `setup.py` shim layer in case this file does not exist,
but there is a `pyproject.toml` file.

We also seem to need to tweak the shim layer with the PKG_VERSION,
otherwise the detected version is 0.0.0.
We will need to see if this will be fixed later in setuptools{-scm}.

Signed-off-by: Alexandru Ardelean <ardeleanalex@gmail.com>
---
 lang/python/python3-host.mk    | 9 ++++++++-
 lang/python/python3-package.mk | 3 ++-
 lang/python/setup.py.shim      | 6 ++++++
 3 files changed, 16 insertions(+), 2 deletions(-)
 create mode 100644 lang/python/setup.py.shim

diff --git a/lang/python/python3-host.mk b/lang/python/python3-host.mk
index 9366b78d9e..8a05c332cf 100644
--- a/lang/python/python3-host.mk
+++ b/lang/python/python3-host.mk
@@ -51,6 +51,12 @@ HOST_PYTHON3_PIP:=$(STAGING_DIR_HOSTPKG)/bin/pip$(PYTHON3_VERSION)
 
 HOST_PYTHON3_PIP_CACHE_DIR:=$(DL_DIR)/pip-cache
 
+define SetupPyShim
+	if [ -f $(1)/pyproject.toml ] && [ ! -f $(1)/setup.py ] ; then \
+		$(CP) $(python3_mk_path)setup.py.shim $(1)setup.py ; \
+	fi
+endef
+
 # Multiple concurrent pip processes can lead to errors or unexpected results: https://github.com/pypa/pip/issues/2361
 # $(1) => packages to install
 define HostPython3/PipInstall
@@ -75,8 +81,9 @@ endef
 # $(2) => additional arguments to setup.py
 # $(3) => additional variables
 define HostPython3/ModSetup
+	$(call SetupPyShim,$(HOST_BUILD_DIR)/$(strip $(1)))
 	$(call HostPython3/Run, \
 		$(HOST_BUILD_DIR)/$(strip $(1)), \
 		setup.py $(2), \
-		$(3))
+		$(3) PY_PKG_VERSION=$(PKG_VERSION))
 endef
diff --git a/lang/python/python3-package.mk b/lang/python/python3-package.mk
index c2617f69ce..a24892ac57 100644
--- a/lang/python/python3-package.mk
+++ b/lang/python/python3-package.mk
@@ -62,10 +62,11 @@ endef
 # $(3) => additional variables
 define Python3/ModSetup
 	$(INSTALL_DIR) $(PKG_INSTALL_DIR)/$(PYTHON3_PKG_DIR)
+	$(call SetupPyShim,$(PKG_BUILD_DIR)/$(strip $(1)))
 	$(call Python3/Run, \
 		$(PKG_BUILD_DIR)/$(strip $(1)), \
 		setup.py $(2), \
-		$(3))
+		$(3) PY_PKG_VERSION=$(PKG_VERSION))
 endef
 
 define Python3/FixShebang
diff --git a/lang/python/setup.py.shim b/lang/python/setup.py.shim
new file mode 100644
index 0000000000..b309abc024
--- /dev/null
+++ b/lang/python/setup.py.shim
@@ -0,0 +1,6 @@
+import os
+import setuptools
+
+# FIXME: see about getting rid of PY_PKG_VERSION asap when setuptools handles this correctly
+if __name__ == "__main__":
+    setuptools.setup(version=os.environ['PY_PKG_VERSION'])