view rust/hg-cpython/src/conversion.rs @ 44202:a7f8160cc4e4

setup: don't skip the search for global hg.exe if there is no local instance

The point of trying not to blindly execute `hg` on Windows is that the local
hg.exe would be given precedence, and if py3 isn't on PATH, it errors out with a
modal dialog.  But that's not a problem if there is no local executable that
could be run.

The problem that I recently ran into was I upgraded the repo format to use zstd.
But doing a `make clean` deletes all of the supporting libraries, causing the
next run to abort with a message about not understanding the
`revlog-compression-zstd` requirement.  By getting rid of the local executable
in the previous commit when cleaning, we avoid leaving a broken executable
around, and avoid the py3 PATH problem too.  There is still a small hole in that
`hg.exe` needs to be deleted before switching between py2/py3/PyOxidizer builds,
because the zstd module won't load.  But that seems like good hygiene anyway.

Differential Revision: https://phab.mercurial-scm.org/D8038

// conversion.rs
//
// Copyright 2019 Georges Racinet <[e-mail]>
//
// This software may be used and distributed according to the terms of the
// GNU General Public License version 2 or any later version.

//! Bindings for the hg::ancestors module provided by the
//! `hg-core` crate. From Python, this will be seen as `rustext.ancestor`

use cpython::{ObjectProtocol, PyObject, PyResult, Python};
use hg::Revision;
use std::iter::FromIterator;

/// Utility function to convert a Python iterable into various collections
///
/// We need this in particular to feed to various methods of inner objects
/// with `impl IntoIterator<Item=Revision>` arguments, because
/// a `PyErr` can arise at each step of iteration, whereas these methods
/// expect iterables over `Revision`, not over some `Result<Revision, PyErr>`
pub fn rev_pyiter_collect<C>(py: Python, revs: &PyObject) -> PyResult<C>
where
    C: FromIterator<Revision>,
{
    revs.iter(py)?
        .map(|r| r.and_then(|o| o.extract::<Revision>(py)))
        .collect()
}