Display exact versions of interpreters

[gaborbernat]

Sometimes it's handy to know the minor version of the python, I find would be very useful if the --version would display not just the major version, but also the version data in a third column:

py --list

┌─────────┬─────────────────────┐
│ Version ┆ Path                │
╞═════════╪═════════════════════╡
│ 3.10    ┆ /usr/bin/python3.10 │
├╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┤
│ 3.9     ┆ /usr/bin/python3.9  │
└─────────┴─────────────────────┘

For example in the above case the following two values taken from sys.version:

3.10.0b1 (default, May 17 2021, 07:59:37) [GCC 10.2.0]
3.9.4 (default, Apr 20 2021, 15:51:38) [GCC 10.2.0]

[brettcannon]

What is the motivation of wanting to have all of this information for all Python interpreters instead of a specific interpreter. E.g. why isn't py -3.10 --version or py -3.10 -c "import sys; print(sys.version)" not enough? Or is this purely for convenience?

A key reason I'm asking is as of right now the Launcher doesn't need to run any Python code or do anything with its output. And my experience with the Python extension for VS Code has taught me that plenty of people have custom Python interpreters that spew out a ton of "extra" stuff when launched, which means this unfortunately wouldn't be as simple as simply reading the stdout of executing the -c example.

[gaborbernat]

Convenience, it would be nice to see all versions installed in one place.

A key reason I'm asking is, as of right now, the Launcher doesn't need to run any Python code or do anything with its output.

How does python-launcher know the version of the executable python?

And my experience with the Python extension for VS Code has taught me that plenty of people have custom Python interpreters that spew out a ton of "extra" stuff when launched, which means this, unfortunately, wouldn't be as simple as simply reading the stdout of executing the -c example.

Guess you'd need to do the same thing virtualenv does, write the information into a temporary JSON file and read that? Granted, this would add some code complexity.

[brettcannon]

How does python-launcher know the version of the executable python?

Parses the file name, e.g. /usr/bin/python3.8 is 3.8.

Guess you'd need to do the same thing virtualenv does, write the information into a temporary JSON file and read that?

Either that or a local socket to ferry the information across.

[gaborbernat]

So what about when python3.8 is not available on path, but only unversioned python?

[brettcannon]

Unless it's coming from a virtual environment via $VIRTUAL_ENV or a .venv directory then it is ignored.