rust/hg-cpython/src/exceptions.rs

hooklib: fix detection of successors for changeset_obsoleted

Provide a hook for obsutil.getobsolete to be used with either a
transaction or the changes item of the transaction, since hooks only
have access to the latter. Use that to find the correct list of
revisions with obsmarkers, even new ones, and then filter out revisions
with known successors.

Move the processing from pretxnclose to txnclose as the transaction
access itself is no longer necessary. This is more in line with notify
and ensures that sanity checks can abort the transaction first.

Differential Revision: https://phab.mercurial-scm.org/D8575

// ancestors.rs
//
// Copyright 2018 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 Rust errors
//!
//! [`GraphError`] exposes `hg::GraphError` as a subclass of `ValueError`
//! but some variants of `hg::GraphError` can be converted directly to other
//! existing Python exceptions if appropriate.
//!
//! [`GraphError`]: struct.GraphError.html
use cpython::{
    exc::{RuntimeError, ValueError},
    py_exception, PyErr, Python,
};
use hg;

py_exception!(rustext, GraphError, ValueError);

impl GraphError {
    pub fn pynew(py: Python, inner: hg::GraphError) -> PyErr {
        match inner {
            hg::GraphError::ParentOutOfRange(r) => {
                GraphError::new(py, ("ParentOutOfRange", r))
            }
            hg::GraphError::WorkingDirectoryUnsupported => {
                match py
                    .import("mercurial.error")
                    .and_then(|m| m.get(py, "WdirUnsupported"))
                {
                    Err(e) => e,
                    Ok(cls) => PyErr::from_instance(py, cls),
                }
            }
        }
    }
}

py_exception!(rustext, HgPathPyError, RuntimeError);
py_exception!(rustext, FallbackError, RuntimeError);
py_exception!(shared_ref, AlreadyBorrowed, RuntimeError);