Work-a-round: Split venv creation by using "--without-pip" and later "ensurepip"

See: https://github.com/YunoHost/issues/issues/1960

scripts/install

@@ -103,7 +103,12 @@ ynh_system_user_create --username="$app" --home_dir="$final_path" --use_shell
 #=================================================
 ynh_script_progression --message="Install project via pip..." --weight=80
 
-python3 -m venv "${final_path}/venv"
+# Always recreate everything fresh with current python version
+ynh_secure_remove "${final_path}/venv"
+
+# Skip pip because of: https://github.com/YunoHost/issues/issues/1960
+python3 -m venv --without-pip "${final_path}/venv"
+
 cp ../conf/requirements.txt "$final_path/requirements.txt"
 chown -R "$app:" "$final_path"
 
@@ -112,8 +117,9 @@ chown -R "$app:" "$final_path"
 	set +o nounset
 	source "${final_path}/venv/bin/activate"
 	set -o nounset
-	ynh_exec_as $app $final_path/venv/bin/pip install --upgrade pip
+	ynh_exec_as $app $final_path/venv/bin/python3 -m ensurepip
-	ynh_exec_as $app $final_path/venv/bin/pip install -r "$final_path/requirements.txt"
+	ynh_exec_as $app $final_path/venv/bin/pip3 install --upgrade wheel pip setuptools
+	ynh_exec_as $app $final_path/venv/bin/pip3 install --no-deps -r "$final_path/requirements.txt"
 )
 
 #=================================================

scripts/restore

@@ -82,6 +82,29 @@ ynh_script_progression --message="Reinstalling dependencies..." --weight=40
 
 ynh_exec_warn_less ynh_install_app_dependencies "$pkg_dependencies"
 
+#=================================================
+# REINSTALL PYTHON VIRTUALENV
+# Maybe the backup contains a other Python version
+#=================================================
+ynh_script_progression --message="Upgrade Python virtualenv..." --weight=50
+
+# Always recreate everything fresh with current python version
+ynh_secure_remove "${final_path}/venv"
+
+# Skip pip because of: https://github.com/YunoHost/issues/issues/1960
+python3 -m venv --without-pip "${final_path}/venv"
+chown -R "$app:" "$final_path"
+
+#run source in a 'sub shell'
+(
+	set +o nounset
+	source "${final_path}/venv/bin/activate"
+	set -o nounset
+	ynh_exec_as $app $final_path/venv/bin/python3 -m ensurepip
+	ynh_exec_as $app $final_path/venv/bin/pip3 install --upgrade wheel pip setuptools
+	ynh_exec_as $app $final_path/venv/bin/pip3 install --no-deps -r "$final_path/requirements.txt"
+)
+
 #=================================================
 # RESTORE THE PostgreSQL DATABASE
 #=================================================

scripts/upgrade

@@ -87,7 +87,12 @@ ynh_add_systemd_config --service="$app" --template="django_example_ynh.service"
 #=================================================
 ynh_script_progression --message="Upgrade project via pip..." --weight=80
 
-python3 -m venv "${final_path}/venv"
+# Always recreate everything fresh with current python version
+ynh_secure_remove "${final_path}/venv"
+
+# Skip pip because of: https://github.com/YunoHost/issues/issues/1960
+python3 -m venv --without-pip "${final_path}/venv"
+
 cp ../conf/requirements.txt "$final_path/requirements.txt"
 chown -R "$app:" "$final_path"
 
@@ -96,8 +101,9 @@ chown -R "$app:" "$final_path"
 	set +o nounset
 	source "${final_path}/venv/bin/activate"
 	set -o nounset
-	ynh_exec_as $app $final_path/venv/bin/pip install --upgrade pip
+	ynh_exec_as $app $final_path/venv/bin/python3 -m ensurepip
-	ynh_exec_as $app $final_path/venv/bin/pip install -r "$final_path/requirements.txt"
+	ynh_exec_as $app $final_path/venv/bin/pip3 install --upgrade wheel pip setuptools
+	ynh_exec_as $app $final_path/venv/bin/pip3 install --no-deps -r "$final_path/requirements.txt"
 )
 
 #=================================================