On Sun, Nov 20, 2022 at 3:56 PM Alexander Kanavin <alex.kanavin@gmail.com> wrote:
Python community has no plans for python4 whatsoever. Anything but gentle and steady evolution won’t be well received.

https://www.techrepublic.com/article/programming-languages-why-python-4-0-will-probably-never-arrive-according-to-its-creator/

Good news article although it does not say that python3 and python are analogous and python package does not explicitly install python binary or symlink either so it’s left up to how distros want to presume it. If we want to do that then it would be prudent to see what other distributions are doing in this regard. So we are not alone in case trouble arises 


Alex

On Mon 21. Nov 2022 at 0.17, Khem Raj <raj.khem@gmail.com> wrote:


On Sun, Nov 20, 2022 at 9:52 AM Markus Volk <f_l_k@t-online.de> wrote:
Currently /usr/bin/python is provided by the python2 package. If python2
is not installed, the built image lacks a provider for it.
This results in failed scripts when using '/usr/bin/python' shebang.

This patch adds a /usr/bin/python symlink for python3 to fix this issue.
For images containing python2 and python3, the do_rootfs task will fail
because now both of them provide the same file.
To allow this corner case, a DISTRO_FEATURE 'python2' has been introduced which,
if set, will prevent python3 from creating the symlink.

The link is created with relative path because using an absolute path would fail
for native and nativesdk.

What happens if and when python4 comes ?
This might get us into same mess we had migrating python2 to 3



Signed-off-by: Markus Volk <f_l_k@t-online.de>
---
 meta/recipes-devtools/python/python3/python3-manifest.json | 1 +
 meta/recipes-devtools/python/python3_3.11.0.bb             | 4 ++++
 2 files changed, 5 insertions(+)

diff --git a/meta/recipes-devtools/python/python3/python3-manifest.json b/meta/recipes-devtools/python/python3/python3-manifest.json
index 64203cf0fc..7b6f509a45 100644
--- a/meta/recipes-devtools/python/python3/python3-manifest.json
+++ b/meta/recipes-devtools/python/python3/python3-manifest.json
@@ -203,6 +203,7 @@
         "files": [
             "${bindir}/python${PYTHON_MAJMIN}",
             "${bindir}/python${PYTHON_MAJMIN}.real",
+            "${bindir}/python",
             "${bindir}/python3",
             "${includedir}/python${PYTHON_MAJMIN}/pyconfig*.h",
             "${libdir}/python${PYTHON_MAJMIN}/UserDict.py",
diff --git a/meta/recipes-devtools/python/python3_3.11.0.bb b/meta/recipes-devtools/python/python3_3.11.0.bb
index 92a1f69320..18b631f79d 100644
--- a/meta/recipes-devtools/python/python3_3.11.0.bb
+++ b/meta/recipes-devtools/python/python3_3.11.0.bb
@@ -144,6 +144,7 @@ do_install:prepend() {

 do_install:append:class-target() {
         oe_multilib_header python${PYTHON_MAJMIN}/pyconfig.h
+        ${@bb.utils.contains('DISTRO_FEATURES', 'python2', '', 'ln -sf ./python3 ${D}${bindir}/python', d)}
 }

 do_install:append:class-native() {
@@ -156,6 +157,7 @@ do_install:append:class-native() {
         # (these often end up too long for the #! parser in the kernel as the
         # buffer is 128 bytes long).
         ln -s python3-native/python3 ${D}${bindir}/nativepython3
+        ${@bb.utils.contains('DISTRO_FEATURES', 'python2', '', 'ln -sf ./python3-native/python3 ${D}${bindir}/nativepython', d)}

         # Remove the opt-1.pyc and opt-2.pyc files. There are over 3,000 of them
         # and the overhead in each recipe-sysroot-native isn't worth it, particularly
@@ -213,6 +215,7 @@ do_install:append() {
 }

 do_install:append:class-nativesdk () {
+    ${@bb.utils.contains('DISTRO_FEATURES', 'python2', '', 'ln -sf ./python3 ${D}${bindir}/python', d)}
     # Make sure we use /usr/bin/env python
     for PYTHSCRIPT in `grep -rIl ${bindir}/python ${D}${bindir}`; do
          sed -i -e '1s|^#!.*|#!/usr/bin/env python3|' $PYTHSCRIPT
@@ -376,6 +379,7 @@ RRECOMMENDS:${PN}-crypt:append:class-nativesdk = " ${MLPREFIX}openssl ${MLPREFIX

 # For historical reasons PN is empty and provided by python3-modules
 FILES:${PN} = ""
+RPROVIDES:${PN} = "${@bb.utils.contains('DISTRO_FEATURES', 'python2', '', '${bindir}/python', d)}"
 RPROVIDES:${PN}-modules = "${PN}"

 FILES:${PN}-pydoc += "${bindir}/pydoc${PYTHON_MAJMIN} ${bindir}/pydoc3"
--
2.34.1





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