The following actions failed │ λ build conf-python-2-7 1.2

[Chaos-Crypto]

Hello， when I run the following command，it occur some error， could you give me some suggests?

$ opam pin add fstar --dev-repo
[NOTE] Package fstar is already pinned to git://github.com/FStarLang/FStar (version 2021.12.31dev).
[fstar.2021.12.31dev] no changes from git://github.com/FStarLang/FStar
fstar is now pinned to git://github.com/FStarLang/FStar (version 2021.12.31~dev)

The following actions will be performed:
∗ install conf-python-2-7 1.2 [required by z3]
∗ install z3 4.8.5 [required by fstar]
∗ install fstar 2021.12.31~dev*
===== ∗ 3 =====
Do you want to continue? [Y/n] y

[z3.4.8.5] downloaded from https://github.com/Z3Prover/z3/archive/Z3-4.8.5.tar.gz

[ERROR] The compilation of conf-python-2-7 failed at "dash.exe -ec python2.7 test.py".

#=== ERROR while compiling conf-python-2-7.1.2 ================================#

context 2.0.8 | win32/x86_64 | ocaml-variants.4.12.0+mingw64c | git://github.com/fdopen/opam-repository-ming

w.git#opam2

path ~/.opam/ocaml-variants.4.12.0+mingw64c/.opam-switch/build/conf-python-2-7.1.2

command dash.exe -ec python2.7 test.py

exit-code 127

env-file ~/.opam/log/conf-python-2-7-20960-1872ec.env

output-file ~/.opam/log/conf-python-2-7-20960-1872ec.out

output

dash: 1: python2.7: not found

<><> Error report <><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>

┌─ The following actions failed
│ λ build conf-python-2-7 1.2
└─
╶─ No changes have been performed
[NOTE] Pinning command successful, but your installed packages may be out of sync.

[tahina-pro]

It seems that a system package required by conf-python-2-7 is absent. To know which one, I'd suggest using depext following https://fdopen.github.io/opam-repository-mingw/depext-cygwin/

[tahina-pro]

In fact, you need to install Python 2.7 via Cygwin (you need to use Cygwin Python, not Windows Python), it seems that depext does not detect that missing package.

[Chaos-Crypto]

Could you help me to give some concrete steps?

[SwampertX]

Having the same problem while installing via OPAM. However, I found that z3>=4.8.13 (latest is 4.11.2) would no longer need the deprecated Python 2.7 and uses Python 3 instead. I see that the version is intentionally pinned; any chance we could bump it?

[SwampertX]

Related: #2431

[ncihnegn]

Nowadays macOS does not come with python2.

[gebner]

This should be fixed by #3069