[edk2-devel] [PATCH v2] edksetup.sh: Simplify SetupPython3 and SetupPython functions.

[Leif Lindholm]

+Bob, Liming, Zhijux

On Mon, Jul 15, 2019 at 08:36:06PM -0600, Rebecca Cran wrote:
> On Linux, "whereis" matches python3, python3.7, as well as
> man pages, libs etc.  While on macOS it only matches the specified
> name, and so misses python3.7. Improve this by looping over
> potential version numbers and seeing if such a binary exists and
> can be executed.

So, let's start by admitting I didn't bother reviewing the existing
code very closely when it was first merged - just verifying it looked
like it may be doing what it intends to do (on Linux, sorry).

Looking more closely now, I have to say I'm not a fan.
Effectively what it does is to pick the highest-version-number python
installed in the system, regardless of what the administrator has set
as the system default - and certainly likely to.

This seems likely to lead to a really fun debugging session for
someone down the line.

So first of all, I would like to understand why we're doing this at
all? Are we likely to see installations that have a python3.7 binary,
but no python3?

If we _are_ keeping it, I would really rather rewrite this as
something that walks PATH and looks at wildcard matches rather than
something that makes assumptions of maximum version numbers.

i.e.

PYTHONS=
IFS=":"

for dir in $PATH; do
    for file in $dir/python3\.*; do
        if [ -f $file ]; then
            PYTHONS=$file:$PYTHONS
        fi
    done
done

IFS=" "

(Of course, we would also need to filter out -m versions.

Or we could assume people have a functional python3 on the PATH and
would like to use that?

Best Regards,

Leif

> Signed-off-by: Rebecca Cran <rebecca at bsdio.com>
> ---
>  edksetup.sh | 44 +++++++-------------------------------------
>  1 file changed, 7 insertions(+), 37 deletions(-)
> 
> diff --git a/edksetup.sh b/edksetup.sh
> index 06d2f041e6..5b90e55ed8 100755
> --- a/edksetup.sh
> +++ b/edksetup.sh
> @@ -107,24 +107,10 @@ function SetupEnv()
>  
>  function SetupPython3()
>  {
> -  if [ $origin_version ];then
> -    origin_version=
> -  fi
> -  for python in $(whereis python3)
> -  do
> -    python=$(echo $python | grep "[[:digit:]]$" || true)
> -    python_version=${python##*python}
> -    if [ -z "${python_version}" ] || (! command -v $python >/dev/null 2>&1);then
> -      continue
> -    fi
> -    if [ -z $origin_version ];then
> -      origin_version=$python_version
> -      export PYTHON_COMMAND=$python
> -      continue
> -    fi
> -      if [[ "$origin_version" < "$python_version" ]]; then
> -      origin_version=$python_version
> +  for ((pyver=15; pyver>=1; --pyver)); do
> +    if python=$(command -v python3.$pyver); then
>        export PYTHON_COMMAND=$python
> +      break
>      fi
>    done
>    return 0
> @@ -146,27 +132,11 @@ function SetupPython()
>      SetupPython3
>    fi
>  
> -  if [ $PYTHON3_ENABLE ] && [ $PYTHON3_ENABLE != TRUE ]
> -  then
> -    if [ $origin_version ];then
> -      origin_version=
> -    fi
> -    for python in $(whereis python2)
> -    do
> -      python=$(echo $python | grep "[[:digit:]]$" || true)
> -      python_version=${python##*python}
> -      if [ -z "${python_version}" ] || (! command -v $python >/dev/null 2>&1);then
> -        continue
> -      fi
> -      if [ -z $origin_version ]
> -      then
> -        origin_version=$python_version
> -        export PYTHON_COMMAND=$python
> -        continue
> -      fi
> -      if [[ "$origin_version" < "$python_version" ]]; then
> -        origin_version=$python_version
> +  if [ -n "$PYTHON3_ENABLE" ] && [ "$PYTHON3_ENABLE" != "TRUE" ]; then
> +    for ((pyver=10; pyver>=1; --pyver)); do
> +      if python=$(command -v python2.$pyver); then
>          export PYTHON_COMMAND=$python
> +        break
>        fi
>      done
>      return 0
> -- 
> 2.22.0
> 

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