From 391f0dcde2695c89759dd73773b3fa38144a8409 Mon Sep 17 00:00:00 2001
From: Julien Palard <julien@palard.fr>
Date: Tue, 7 Dec 2021 11:28:47 +0100
Subject: [PATCH] Initial commit

---
 README.md         | 116 ++++++++++++++++++++++++++++++++++++++++++++++
 compile-python.sh |  66 ++++++++++++++++++++++++++
 2 files changed, 182 insertions(+)
 create mode 100644 README.md
 create mode 100644 compile-python.sh

diff --git a/README.md b/README.md
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+# Compile Python
+
+This is a small bash script to compile one or multiple Python versions.
+
+I use it on my laptop, using Debian, but it may work on other distribs.
+
+On Debian (and Debian-based distribs) it needs the following
+dependencies:
+
+```
+apt install make build-essential libssl-dev zlib1g-dev libbz2-dev \
+ibreadline-dev libsqlite3-dev wget curl llvm libncursesw5-dev \
+xz-utils tk-dev libxml2-dev libxmlsec1-dev libffi-dev liblzma-dev
+```
+
+
+## Usage
+
+Clone the repo anywhere, then in your `~/.bashrc` add:
+
+    source PATH/To/THE/REPO/compile-python.sh
+
+
+TL;DR:
+
+```bash
+$ compile-pythons
+$ python3.6 --version
+Python 3.6.15
+$ python3.7 --version
+Python 3.7.12
+$ python3.8 --version
+Python 3.8.12
+$ python3.9 --version
+Python 3.9.9
+$ python3.10 --version
+Python 3.10.1
+$ python3.11 --version
+Python 3.11.0a2
+```
+
+
+## How it works
+
+It downloads official Python sources (from
+[https://www.python.org/ftp/python/](https://www.python.org/ftp/python/)),
+then compiles them using `--with-pydebug` (it's a dev tool, don't use
+it in production! Rely on your distrib in production!), and
+`--prefix=~/.local`, and finally installs it using `make altinstall`.
+
+Anyway it's ~67 lines of code, maybe just read it.
+
+
+## Be nice with distrib' provided Python
+
+`compile-python` only produces binaries on the form `pythonX.Y` (like
+`python3.8`), so `python3` and `python` will always point to your
+distrib' Python.
+
+Don't hesitate to `apt install python-is-python3` if you want `python`
+to be `python3`.
+
+
+## Functions
+
+The file declares 3 functions:
+
+- `compile-pythons`: To compile a set of usefull Python versions.
+- `compile-python`: To compile a given Python version (has autocompletion).
+- `venv`: Just a wrapper to `python -m venv` that I like to use daily.
+
+Using a function don't force you to use the others, they are **not** related.
+
+
+### `compile-pythons`
+
+This is probably the one you're seeking, it compiles a bunch of
+usefull Python verisons, typically usefull if you use
+[tox](https://tox.wiki/en/latest/) and need multiple Python versions
+to test your project.
+
+
+### `compile-python`
+
+This one is used by `compile-python` but you can use it manually, like:
+
+    compile-python 3.10.1
+
+
+### `venv`
+
+A bit unrelated to the two others, here for historical reasons, this
+is how I create venvs. I use it like:
+
+```bash
+$ venv
+```
+
+If the venv does not exists it's created, if it exist it's just activated.
+
+It takes an optional parameter: the Python version to use, like `venv
+3.10` or `venv 3.6`.
+
+The venv prompt takes the name of the current directory plus the
+version, like:
+
+    (compile-python)(py3.10.0) mdk@seaph:~/ $
+
+which I find usefull, but feel free to not use it.
+
+
+## Why not using `pyenv`?
+
+I know `pyenv` exists, I even used it back in the time. I did not
+appreciated the `shims` part (I'm not saying it's bad), so I tried
+myself as something more simple: just build Python and that's it.
diff --git a/compile-python.sh b/compile-python.sh
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+venv()
+{
+    # Usage:
+    #
+    #    venv: Creates a venv with the current `python` version.
+    #    venv VERSION: Create a venv with given version.
+    #
+    # Example:
+    #
+    #    venv 3.10
+    deactivate 2>/dev/null
+    if ! [[ -d .venv ]]
+    then
+        python$1 -m venv --prompt "$(basename "$PWD"))(py$(python$1 --version | cut -d' ' -f2)" .venv
+    fi
+    source .venv/bin/activate
+}
+
+compile-python()
+{
+    # Inspired from the great https://gitlab.com/python-devs/ci-images/
+    # Thanks Barry Warsaw.
+
+    # Needs:
+    # sudo apt-get update; sudo apt-get install make build-essential libssl-dev zlib1g-dev \
+    # libbz2-dev libreadline-dev libsqlite3-dev wget curl llvm \
+    # libncursesw5-dev xz-utils tk-dev libxml2-dev libxmlsec1-dev libffi-dev liblzma-dev
+
+    local PY_VERSION="$1"
+    local BETA="$2"
+    local FLAGS=""
+    if dpkg --compare-versions "$PY_VERSION" ge 3.8.0  # Since 3.8.0 debug builds are ABI compatible, let's use them.
+    then
+        FLAGS="--with-pydebug"
+    fi
+    local URL="https://www.python.org/ftp/python"
+    (
+        cd /tmp
+        wget -qO- $URL/$PY_VERSION/Python-$PY_VERSION$BETA.tgz | tar -xzf - || (
+            echo "Version not found, check on $URL."
+        )
+        [ -d Python-$PY_VERSION$BETA ] && (cd Python-$PY_VERSION$BETA; ./configure $FLAGS --prefix=$HOME/.local/ && make -j $(nproc) && make altinstall) &&
+            rm -r Python-$PY_VERSION$BETA
+    )
+}
+
+compile-pythons()
+{
+    # Compiles a usefull set of Python versions.
+    compile-python 3.5.10 &
+    compile-python 3.6.15 &
+    compile-python 3.7.12 &
+    compile-python 3.8.12 &
+    compile-python 3.9.9 &
+    compile-python 3.10.1 &
+    compile-python 3.11.0 a2 &
+    wait
+}
+
+_compile_python()
+{
+    COMPREPLY=( $( compgen -W '$( command curl -s https://www.python.org/ftp/python/  | grep -o ">[0-9.]\+/<" | sed "s/^>//;s|/<$||" )' -- "${COMP_WORDS[COMP_CWORD]}") )
+}
+complete -F _compile_python compile-python
+
+PATH="$PATH:$HOME/.local/bin"