[gentoo-dev] [PATCH 1/2] distutils-r1.eclass: Set script shebangs to venv in PEP 517

[Michał Górny]

Alter the shebangs of generated scripts to point out the to venv Python
executables in PEP 517 mode.  Otherwise, the executables are run with
system Python during the test run and therefore do not use the venv.

For convenience, rather than modifying them back just copy them
immediately into the python-exec directory.  This means that instead of
reverting some of our python_compile() changes in python_install()
and then moving scripts to the python-exec directory, we can just
discard /usr/bin and let the wrapping logic recreate it.

While at it, stop repeating ${root}${EPREFIX}/usr/bin multiple times
in python_compile().  Just shove it into a helper variable.  Also move
pyvenv.cfg inside bindir for convenience — Python is fine with either
location.

Signed-off-by: Michał Górny <mgorny@g.o>
---
 eclass/distutils-r1.eclass | 39 +++++++++++++++++++++++---------------
 1 file changed, 24 insertions(+), 15 deletions(-)

diff --git a/eclass/distutils-r1.eclass b/eclass/distutils-r1.eclass
index 9b2dc841054c..cf3eb639d5e6 100644
--- a/eclass/distutils-r1.eclass
+++ b/eclass/distutils-r1.eclass
@@ -982,14 +982,30 @@ distutils-r1_python_compile() {
 			esetup.py clean -a
 		fi
 
+		# copy executables to python-exec directory
+		# we do it early so that we can alter bindir recklessly
+		local bindir=${root}${EPREFIX}/usr/bin
+		local rscriptdir=${root}$(python_get_scriptdir)
+		[[ -d ${rscriptdir} ]] &&
+			die "${rscriptdir} should not exist!"
+		if [[ -d ${bindir} ]]; then
+			mkdir -p "${rscriptdir}" || die
+			cp -a --reflink=auto "${bindir}"/. "${rscriptdir}"/ || die
+		fi
+
 		# enable venv magic inside the install tree
-		mkdir -p "${root}${EPREFIX}"/usr/bin || die
-		ln -s "${PYTHON}" "${root}${EPREFIX}/usr/bin/${EPYTHON}" || die
-		ln -s "${EPYTHON}" "${root}${EPREFIX}/usr/bin/python3" || die
-		ln -s "${EPYTHON}" "${root}${EPREFIX}/usr/bin/python" || die
-		cat > "${root}${EPREFIX}"/usr/pyvenv.cfg <<-EOF || die
+		mkdir -p "${bindir}" || die
+		ln -s "${PYTHON}" "${bindir}/${EPYTHON}" || die
+		ln -s "${EPYTHON}" "${bindir}/python3" || die
+		ln -s "${EPYTHON}" "${bindir}/python" || die
+		cat > "${bindir}"/pyvenv.cfg <<-EOF || die
 			include-system-site-packages = true
 		EOF
+
+		# we need to change shebangs to point to the venv-python
+		find "${bindir}" -type f -exec sed -i \
+			-e "1s@^#!\(${EPREFIX}/usr/bin/\(python\|pypy\)\)@#!${root}\1@" \
+			{} + || die
 	fi
 }
 
@@ -1105,16 +1121,9 @@ distutils-r1_python_install() {
 	local scriptdir=${EPREFIX}/usr/bin
 	if [[ ${DISTUTILS_USE_PEP517} ]]; then
 		local root=${BUILD_DIR}/install
-		local rscriptdir=${root}$(python_get_scriptdir)
-		[[ -d ${rscriptdir} ]] &&
-			die "${rscriptdir} should not exist!"
-		# remove venv magic
-		rm "${root}${EPREFIX}"/usr/{pyvenv.cfg,bin/{python,python3,${EPYTHON}}} || die
-		find "${root}${EPREFIX}"/usr/bin -empty -delete || die
-		if [[ ! ${DISTUTILS_SINGLE_IMPL} && -d ${root}${EPREFIX}/usr/bin ]]; then
-			mkdir -p "${rscriptdir%/*}" || die
-			mv "${root}${EPREFIX}/usr/bin" "${rscriptdir}" || die
-		fi
+		# remove the altered bindir, executables from the package
+		# are already in scriptdir
+		rm -r "${root}${scriptdir}" || die
 	else
 		local root=${D%/}/_${EPYTHON}
 		[[ ${DISTUTILS_SINGLE_IMPL} ]] && root=${D%/}
-- 
2.35.0